Mycotoxins in poultry – External signs can give a hint

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Part 4: Paleness

By Dr. Inge Heinzl, Editor and Marisabel Caballero, Global Technical Manager Poultry

We already showed bad feathering, mouth and beak lesions, bone issues, and foot pad lesions as signs of mycotoxin contamination in the feed, but there is another indicator: paleness. Paleness can signify a low count of red blood cells resulting from blood loss or inadequate production of these cells. Other possibilities are higher bilirubin levels in the blood due to an impaired liver, leading to jaundice or missing pigmentation.

Hen With Pale Comb And Wattles Large
Hen with pale comb and wattles (adapted from Bozzo et al., 2023)

The mycotoxins mainly causing anemia are Aflatoxins, Ochratoxin, DON, and T-2 toxin

Anemia can be diagnosed using parameters such as red blood cell count, hemoglobin levels, and hematocrit/packed cell volume (PCV). Numerous studies have examined the impact of mycotoxins on hematological parameters. They reveal their propensity to affect red blood cell production by impairing the function of the spleen and inducing hematological alterations. On the other hand, anemia can be caused by blood loss. Due to affecting coagulation factors, mycotoxins can lead to internal hemorrhages. The gut wall damage, probably due to secondary infections such as coccidiosis and necrotic enteritis, can entail bloody diarrhea in various animal species.

Impact on the production of blood cells

Low values of blood parameters such as red blood cells, hemoglobin, and hematocrit can result from inadequate production due to impacted production organs. The World Health Organization (WHO, 1990) and European Commission (European Commission, 2001) have identified hematopoietic tissues as targets for necrosis caused by T-2 toxin. Chu (2003) even stated that “the major lesion of T-2 toxin is its devastating effect on the hematopoietic system in many mammals, including humans”. Pande et al. (2006) suggested that reduced hemoglobin values result from decreased protein synthesis due to mycotoxin contamination, a notion supported by Pronk et al. (2002), who described trichothecenes as potent inhibitors of protein, DNA, and RNA synthesis, particularly affecting tissues with high cell division rates. Additionally, the European Commission (2001) highlighted the sensitivity of red blood cell progenitor cells (in this trial, the cells of mice, rats, and humans) to the toxic effects of T-2 and HT-toxins. DAS also seems to attack the hematopoietic system, as shown in humans (WHO, 1990). A further cause for anemia might be low feed intake or nutrient absorption, which inhibits adequate iron absorption and leads to iron deficiency. In their case report, Bozzo et al. (2023) assumed that renal failure and a resulting impaired excretion capacity caused by OTA might even increase the half-life of the toxins. This would enhance their effects on their target organs, such as the liver and bone marrow, and lead to anemia.

Several studies utilizing different animal species and mycotoxin dosages have been conducted to assess the effects of Aflatoxins, Ochratoxin, and T-2 Toxin on hematological parameters. The following table provides a summary of some of these studies.

Animal species Dosage Impact Reference
T-2 Toxin and other Trichothecenes
Broilers T-2 – 0, 1, 2, and 4 mg T-2 toxin/kg

n=30 per group

Significant reduction in hemoglobin at 1, 2, and 4 ppm; PCV significantly reduced at 4 ppm Pande et al., 2006
Broilers T-2 – 0 and 4 mg/kg diet

n=60 per group

Decrease in hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin concentration Kubena et al., 1989a
Broilers 4, 16, 50, 100, 300 ppm for seven days

n=5-20 chickens per group

Anemia; significant reduction of hematocrit (50 and 100 ppm); survivors had atrophied lymphoid organs and were anemic Hoerr et al., 1982
Yangzhou goslings 0, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0 mg/kg; n=6 per group Red blood cell count decreased in the 2.0 mg/kg group along with an increase in mean corpuscular hemoglobin (p<0.05) and reduced mean platelet volume (P<0.05) Gu et al., 2023
Broilers 2 ppm; 32 birds per group Anemia, as indicated by significantly (P<0.05) lower total erythrocyte count (TEC) values, lower hemoglobin levels, and packed cell volume; additional thrombocytopenia could be the cause of bleeding Yohannes et al., 2013
DON
Broilers 5 and 15 mg/kg of feed for 42 days Decrease in erythrocytes, mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC) at 15 mg/kg; decrease in hematocrit and hemoglobin at both levels of DON.

 

Riahi, 2021
Piglets 0.6 mg/kg and 2.0 mg/kg Significant decrease in mean corpuscular volume Modrá et al., 2013
Broilers 16 mg/kg diet

n=60 per group

Significant decrease in mean corpuscular volume Kubena et al., 1989c
Ochratoxin
Broilers 2 mg/kg diet singly or combined with

DAS 6 mg/kg

Reduced mean corpuscular hemoglobin values Kubena et al., 1994
Broilers 2 mg/kg diet Significant decrease in hemoglobin, hematocrit, mean corpuscular volume and mean corpuscular hemoglobin concentration Kubena et al., 1989b
Aflatoxins
Broilers 2.5 µg/g Decrease in red blood cell count Huff et al., 1988
Broilers ≥1.25 µg/g Significant decrease in hemoglobin and erythrocyte count Tung et al., 1975
AFB1 + OTA
Laying hens Natural feed contamination OTA – 31 ± 3.08 µg/kg and

AFB1 – 5.6 ± 0.33 µg/kg dry weight

Anemia signs (pale appearance of combs and wattles), evidenced by the discoloration of the content of the femoral medullary cavity.

 

Bozzo et al., 2023

 

Table 1: The effects of different mycotoxins on hematological parameters – hematopoiesis

In their meta-analysis, Andretta et al. (2012) reported that the presence of mycotoxins in broiler diets decreased the hematocrit and the hemoglobin concentration by 5% and 15%, and aflatoxin alone decreased the parameters by 6% and 20%.

It should be evident that a simultaneous occurrence of several mycotoxins even aggravates the situation. In an experiment involving Sprague Dawley rats, administering T-2, DON, NIV, ZEA, NEO, and OTB decreased hematocrit and red blood cell counts across all mycotoxins. However, for DON, NIV, ZEN, and OTB, red blood cell values showed partial recovery after 24 hours (Chattopadhyay, 2013). Perhaps the organism learns to cope with the mycotoxins.

The examples show that Trichothecenes, such as T-2 toxin, DON, and others, as well as Ochratoxins and Aflatoxins, impact blood parameters such as hematocrit, hemoglobin, red blood cell count, and mean corpuscular volume. All these changes might lead to paleness of the skin and birds’ feet and combs.

Blood loss caused by bleeding or destruction of erythrocytes

The second possibility for anemia is blood loss due to injuries or lesions. In addition to directly causing hemorrhages, mycotoxins can promote secondary infections such as coccidiosis, which damages the gut and may produce bloody feces.

Parent-Massin (2004) e.g. reports on rapidly progressing coagulation problems after the ingestion of trichothecenes leading to septicemia and massive hemorrhages. Table 2 shows more examples of mycotoxins causing paleness due to blood loss.

Animal species Dosage Impact Reference
T-2 Toxin and other Trichothecenes
Cats T-2 toxin – 0.06-0.1 mg/kg body weight/day Bloody feces, hemorrhages Lutsky et al., 1978
Cats T-2 toxin – 0.08 mg/kg BW every 48 h until death Bloody feces Lutzky and Mor, 1981
Pigeon DAS in oat, sifting Emesis and bloody stools Szathmary (1983)
Calves 0.08, 0.16, 0.32, or 0.6 mg/kg BW per day for 30 days; 1 calf per treatment Bloody feces at doses ≥0.32 mg/kg BW per day Pier et al., 1976
Ochratoxin
Rats Single dosages of 0, 17, or 22 mg/kg BW in 0.1 Mol/L NaHCO3, gavage Multifocal hemorrhages in many organs Albassam et al., 1987
 
DON
Broilers 0, 35, 70, 140, 280, 560, and 1120 mg/kg body weight Ecchymotic hemorrhages throughout the intestinal tract, liver, and musculature; relationship to hemorrhagic anemia syndrome seems warranted Huff et al., 1981
Sterigmatocystin (ST)
10-12-day old chicks (93-101 g) 10 and 14 mg/kg BW intraperitoneal Hemorrhages and foci of necrosis in the liver Sreemannarayana et al., 1987
Aflatoxins
Broiler chickens 100 µg/kg feed Hemorrhages in the liver Abdel-Sattar, 2019
Turkeys 500 and 1000 ppb in the diet Bloody diarrhea, spleens with hemorrhages, petechial hemorrhages in the small intestine Giambrone et al., 1984
Broilers 0, 0.625, 1.25, 2.5, 5.0, and 10.0 mg/kg of diet combined with Infectious Bursal Disease Slight hemorrhages in the skeletal muscles; decreased hematocrit and hemoglobin due to hemolytic anemia. Chang and Hamilton, 1981
Broilers 0, 1, and 2 mg AFB1/kg of diet Downregulation of the genes involved in blood coagulation (coagulation factor IX and X) and upregulation of anticoagulant protein C precursor, an inactivator of coagulation factors Va and VIIIa, and antithrombin-III precursor with 2 mg/kg Yarru, 2009
Pigs 1-4 mg/kg, 4 weeks

0.4-0.8 mg/kg, 10 weeks

Hemorrhages Henry et al., 2001

Table 2: The effects of different mycotoxins on hematological parameters – blood loss

Poor pigmentation

The fourth reason for paleness can be inadequate pigmentation. According to Hy Line (2021), the so-called pale bird syndrome is characterized by poor skin and egg yolk pigmentation and is caused by reduced absorption of fat and carotenoid pigments in compromised birds. This is also the case when the diets contain pigment supplements. Tyczkowski and Hamilton (1986) observed in their experiment with chickens exposed to doses of 1-8 µg of Aflatoxins/g of diet for three weeks that aflatoxins can cause poor pigmentation in chickens, probably by impairing carotenoids absorption but also transport and deposition. Osborne et al. (1982) asserted that carotenoids were significantly (P<0.05) depressed by 2 ppm ochratoxin as well as by 2.5 ppm aflatoxin in the diet.

Another possibility is oxidative stress due to the mycotoxin challenge. As pigments also serve as antioxidants, they may be expended for this purpose and are no longer available for pigmentation.

Paleness in poultry – a reason to think about mycotoxins

Paleness can have different causes, some of which are influenced by mycotoxins. If your chickens or hens are pale, checking the feed concerning mycotoxins is always recommended. A feed analysis can give information about possible contamination (see our tool MasterRisk).

In the case of contamination, effective products binding the mycotoxins and mitigating the adverse effects of these harmful substances can help protect your birds. As paleness is usually not the only effect of mycotoxins but also a decrease in growth, toxin binders can help maintain the performance of your animals.

References:

Abdel-Sattar, Ward Masoud, Kadry Mohamed Sadek, Ahmed Ragab Elbestawy, and Disouky Mohamed Mourad. “The Protective Role of Date Palm (Phoenix Dactylifera Seeds) against Aflatoxicosis in Broiler Chickens Regarding Carcass Characterstics, Hepatic and Renal Biochemical Function Tests and Histopathology.” Journal of World’s Poultry Research 9, no. 2 (June 25, 2019): 59–69. https://doi.org/10.36380/scil.2019.wvj9.

Albassam, M. A., S. I. Yong, R. Bhatnagar, A. K. Sharma, and M. G. Prior. “Histopathologic and Electron Microscopic Studies on the Acute Toxicity of Ochratoxin a in Rats.” Veterinary Pathology 24, no. 5 (September 1987): 427–35. https://doi.org/10.1177/030098588702400510.

Andretta, I., M. Kipper, C.R. Lehnen, and P.A. Lovatto. “Meta-Analysis of the Relationship of Mycotoxins with Biochemical and Hematological Parameters in Broilers.” Poultry Science 91, no. 2 (February 2012): 376–82. https://doi.org/10.3382/ps.2011-01813.

Bhat, RameshV, Y Ramakrishna, SashidharR Beedu, and K.L Munshi. “Outbreak of Trichothecene Mycotoxicosis Associated with Consumption of Mould-Damaged Wheat Products in Kashmir Valley, India.” The Lancet 333, no. 8628 (January 1989): 35–37. https://doi.org/10.1016/s0140-6736(89)91684-x.

Bozzo, Giancarlo, Nicola Pugliese, Rossella Samarelli, Antonella Schiavone, Michela Maria Dimuccio, Elena Circella, Elisabetta Bonerba, Edmondo Ceci, and Antonio Camarda. “Ochratoxin A and Aflatoxin B1 Detection in Laying Hens for Omega 3-Enriched Eggs Production.” Agriculture 13, no. 1 (January 5, 2023): 138. https://doi.org/10.3390/agriculture13010138.

Chang, Chao-Fu, and Pat B. Hamilton. “Increased Severity and New Symptoms of Infectious Bursal Disease during Aflatoxicosis in Broiler Chickens.” Poultry Science 61, no. 6 (June 1982): 1061–68. https://doi.org/10.3382/ps.0611061.

Chattopadhyay, Pronobesh, Amit Agnihotri, Danswerang Ghoyary, Aadesh Upadhyay, Sanjeev Karmakar, and Vijay Veer. “Comparative Hematoxicity of Fusarium Mycotoxin in Experimental Sprague-Dawley Rats.” Toxicology International 20, no. 1 (2013): 25. https://doi.org/10.4103/0971-6580.111552.

European Commission. “Opinion of the Scientific Committee on Food on Fusarium Toxins Part 5: T-2 Toxin and HT-2 Toxin.” Food.ec.europa. Accessed May 30, 2001. https://food.ec.europa.eu/document/download/a859c348-a38e-404c-a2af-c3e29a3a8777_en?filename=sci-com_scf_out88_en.pdf.

Giambrone, J.J., U.L. Diener, N.D. Davis, V.S. Panangala, and F.J. Hoerr. “Effect of Purified Aflatoxin on Turkeys.” Poultry Science 64, no. 5 (May 1985): 859–65. https://doi.org/10.3382/ps.0640859.

Gu, Wang, Qiang Bao, Kaiqi Weng, Jinlu Liu, Shuwen Luo, Jianzhou Chen, Zheng Li, et al. “Effects of T-2 Toxin on Growth Performance, Feather Quality, Tibia Development and Blood Parameters in Yangzhou Goslings.” Poultry Science 102, no. 2 (February 2023): 102382. https://doi.org/10.1016/j.psj.2022.102382.

Henry, H., T. Whitaker, I. Rabban, J. Bowers, D. Park, W. Price, F.X. Bosch, et al. “Aflatoxin M1.” Aflatoxin M1 (JECFA 47, 2001). Accessed July 29, 2024. https://inchem.org/documents/jecfa/jecmono/v47je02.htm.

Hoerr, F., W. Carlton, B. Yagen, and A. Joffe. “Mycotoxicosis Caused by Either T-2 Toxin or Diacetoxyscirpenol in the Diet of Broiler Chickens.” Fundamental and Applied Toxicology 2, no. 3 (May 1982): 121–24. https://doi.org/10.1016/s0272-0590(82)80092-4.

Huff, W.E., J.A. Doerr, P.B. Hamilton, and R.F. Vesonder. “Acute Toxicity of Vomitoxin (Deoxynivalenol) in Broiler Chickens,” Poultry Science 60, no. 7 (July 1981): 1412–14. https://doi.org/10.3382/ps.0601412.

Huff, W.E., R.B. Harvey, L.F. Kubena, and G.E. Rottinghaus. “Toxic Synergism between Aflatoxin and T-2 Toxin in Broiler Chickens.” Poultry Science 67, no. 10 (October 1988): 1418–23. https://doi.org/10.3382/ps.0671418.

Hy-Line. “Mycotoxins: How to deal with the threat of mycotoxicosis.” Hy-Line International. Accessed July 29, 2024. https://www.hyline.com/.

Klein, P. J., T. R. Vleet, J. O. Hall, and R. A. Coulombe. “Dietary Butylated Hydroxytoluene Protects against Aflatoxicosis in Turkey.” Poisonous plants and related toxins, November 24, 2003, 478–83. https://doi.org/10.1079/9780851996141.0478.

Kubena, L.F., R.B. Harvey, T.S. Edrington, and G.E. Rottinghaus. “Influence of Ochratoxin A and Diacetoxyscirpenol Singly and in Combination on Broiler Chickens.” Poultry Science 73, no. 3 (March 1994): 408–15. https://doi.org/10.3382/ps.0730408.

Kubena, L.F., R.B. Harvey, W.E. Huff, D.E. Corrier, T.D. Philipps, and G.E. Rottinghaus. “Influence of Ochratoxin A and T-2 Toxin Singly and in Combination on Broiler Chickens.” Poultry Science 68, no. 7 (July 1989): 867–72. https://doi.org/10.3382/ps.0680867.

Kubena, L.F., R.B. Harvey, W.E. Huff, D.E. Corrier, T.D. Phillips, and G.E. Rottinghaus. “Influence of Ochratoxin A and T-2 Toxin Singly and in Combination on Broiler Chickens.” Poultry Science 68, no. 7 (July 1989): 867–72. https://doi.org/10.3382/ps.0680867.

Kubena, L.F., W.E. Huff, R.B. Harvey, T.D. Phillips, and G.E. Rottinghaus. “Individual and Combined Toxicity of Deoxynivalenol and T-2 Toxin in Broiler Chicks.” Poultry Science 68, no. 5 (May 1989): 622–26. https://doi.org/10.3382/ps.0680622.

Lutsky, I.I., and N. Mor. “Alimentary Toxic Aleukia (Septic Angina, Endemic Panmyelotoxicosis, Alimentary Hemorrhagic Aleukia): T-2 Toxin-Induced Intoxication of Cats.” The American journal of pathology, 1980. https://pubmed.ncbi.nlm.nih.gov/6973281/.

Lutsky, Irving, Natan Mor, Boris Yagen, and Avraham Z. Joffe. “The Role of T-2 Toxin in Experimental Alimentary Toxic Aleukia: A Toxicity Study in Cats.” Toxicology and Applied Pharmacology 43, no. 1 (January 1978): 111–24. https://doi.org/10.1016/s0041-008x(78)80036-2.

MEJ, Pronk, Schothorst RC, and H.P. van Egmond. “Toxicology and Occurrence of Nivalenol, Fusarenon X, Diacetoxyscirpenol, Neosolaniol and 3- and 15- Acetyldeoxynivalenol; a Review of Six Trichothecenes.” Home – Web-based Archive of RIVM Publications, November 7, 2002. https://rivm.openrepository.com/handle/10029/9184.

Modra, Helena, Jana Blahova, Petr Marsalek, Tomas Banoch, Petr Fictum, and Martin Svoboda. “The Effects of Mycotoxin Deoxynivalenol (DON) on Haematological and Biochemical Parameters and Selected Parameters of Oxidative Stress in Piglets.” Neuro Endocrinol Lett. 34, no. Suppl 2 (2013): 84–89.

Osborne, D.J., W.E. Huff, P.B. Hamilton, and H.R. Burmeister. “Comparison of Ochratoxin, Aflatoxin, and T-2 Toxin for Their Effects on Selected Parameters Related to Digestion and Evidence for Specific Metabolism of Carotenoids in Chickens,” Poultry Science 61, no. 8 (August 1982): 1646–52. https://doi.org/10.3382/ps.0611646.

Pande, Vivek, Nitin Kurkure, and A.G. Bhandarkar. “Effect of T-2 Toxin on Growth, Performance and Haematobiochemical Alterations in Broilers .” Indian Journal of Experimental Biology 44, no. 1 (February 2006): 86–88.

Pier , A.C., S.J. Cysewski, J.L. Richard , A.L. Baetz, and L. Mitchell. “Experimental Mycotoxicoses in Calves with Aflatoxin, Ochratoxin, Rubratoxin, and T-2 Toxin.” Proceedings, annual meeting of the United States Animal Health Association, 1976. https://pubmed.ncbi.nlm.nih.gov/1078072/.

Resanovic, Radmila, Ksenija Nesic, Vladimir Nesic, Todor Palic, and Vesna Jacevic. “Mycotoxins in Poultry Production.” Zbornik Matice srpske za prirodne nauke, no. 116 (2009): 7–14. https://doi.org/10.2298/zmspn0916007r.

Riahi, Insaf, Virginie Marquis, Anna Maria Pérez-Vendrell, Joaquim Brufau, Enric Esteve-Garcia, and Antonio J. Ramos. “Effects of Deoxynivalenol-Contaminated Diets on Metabolic and Immunological Parameters in Broiler Chickens.” Animals 11, no. 1 (January 11, 2021): 147. https://doi.org/10.3390/ani11010147.

Sreemannarayana, O., A. A. Frohlich, and R. R. Marquardt. “Acute Toxicity of Sterigmatocystin to Chicks.” Mycopathologia 97, no. 1 (January 1987): 51–59. https://doi.org/10.1007/bf00437331.

Stack, Jim, and Mike Carlson. “Fumonisins in Corn.” DigitalCommons@University of Nebraska – Lincoln, 2003. https://core.ac.uk/download/pdf/188054556.pdf.

Szathmary, C.I. “Trichothecene Toxicoses and Natural Occurrence in Hungary.” Essay. In Ueno, Y: Developments in Food Science IV. Trichothecenes, 229–50. New York: Elsevier, 1983.

Tung, Hsi-Tang, F.W. Cook, R.D. Wyatt, and P.B. Hamilton. “The Anemia Caused by Aflatoxin.” Poultry Science 54, no. 6 (November 1975): 1962–69. https://doi.org/10.3382/ps.0541962.

Tyczkowski, Juliusz K., and Pat B. Hamilton. “Altered Metabolism of Carotenoids during Aflatoxicosis in Young Chickens,” Poultry Science 66, no. 7 (July 1987): 1184–88. https://doi.org/10.3382/ps.0661184.

WHO. “Selected Mycotoxins : Ochratoxins, Trichothecenes, Ergot / Published under the Joint Sponsorship of the United Nations Environment Programme, the International Labour Organisation and the World Health Organization.” World Health Organization, January 1, 1990. https://apps.who.int/iris/handle/10665/39552.

Yohannes, T., A. K. Sharma, S. D. Singh, and V. Sumi. “Experimental Haematobiochemical Alterations in Broiler Chickens Fed with T-2 Toxin and Co-Infected with IBV.” Open Journal of Veterinary Medicine 03, no. 05 (2013): 252–58. https://doi.org/10.4236/ojvm.2013.35040.




Mycotoxins in poultry – External signs can give a hint

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Part 3: Bone disorders and foot pad lesions

By Dr. Inge Heinzl, Editor, and Marisabel Caballero, Global Technical Manager Poultry

 

Bone health is essential for animals and humans. Besides giving structural support, allowing movement, and protecting vital organs, the bones release hormones that are crucial for mineral homeostasis and acid balance and serve as reservoirs of energy and minerals (Guntur & Rosen, 2012; Rath, N.C. & Durairaj, 2022; Suchacki et al., 2017).

Bone disorders and foot pad lesions are considerable challenges in poultry production, especially for fast-growing birds with high final weights. Due to pain, the animals do not move, and dominant, healthy birds may restrict lame birds’ access to feed and water. In consequence, these birds are often culled. Moreover, processing these birds is problematic, and often, they must be discarded or downgraded.

Foot pad lesions, another common issue in poultry production, can also have significant economic implications. On the one hand, pain restricts birds from eating and drinking and reduces weight gain. On the other hand, for many producers, chicken feet constitute a substantial part of the economic value of the bird; therefore, discarding them represents a significant financial loss. Additionally, to push poultry production in the right direction concerning animal health and welfare, a foot pad scoring system at the processing plant is in place in European countries.

Mycotoxins affect bones in different ways

Mycotoxins, depending on their target organs, can have diverse effects on the skeleton of birds. For example, mycotoxins that target the liver can disrupt calcium metabolism, which in turn affects the mineralization of the bones (rickets) and the impairment of chondrocytes can slow down bone growth (e.g., tibial dyschondroplasia). When the kidneys are impacted, urate clearance decreases, plasma uric acid consequently increases, and urate crystals form in the synovial fluid and tendon sheaths of various joints, particularly the hock joints. These examples highlight the complex and varied ways mycotoxins can impact poultry bone health.

Inadequate bone mineralization and strength – Rickets and layer cage fatigue

Sufficient bone mineralization is essential for the stability of the skeleton. Calcium (Ca), Vitamin D, and Phosphorous (P) deficiency leads to inadequate mineralization, weakens the bone, and can cause soft and bent bones or, in the case of layers, cage fatigue – a collapse of the spinal bone- and paralysis. Inadequate bone mineralization can be caused in different ways, among them:

  1. Decrease in the availability of the nutrients necessary for mineralization. This can occur if the digestibility of these nutrients deteriorates
  2. Impact on the Ca/P ratio—A ratio of 1 – 2:1 is vital for adequate bone development (Loughrill et al., 2016). Mycotoxins can alter absorption and transporters for one or both elements, altering their ratio.
  3. Impact on the Vitamin D receptor, affecting its expression or the transporters for Ca and P.

Aflatoxins can impair bone mineralization by different modes of action. An important one is the impairment of the digestibility of Ca and P: Kermanshahi et al. (2007) fed broilers diets with high levels of aflatoxins (0.8 to 1.2 mg AFB1/kg feed) for three weeks, which resulted in a significant reduction of Ca and P digestibility. Other researchers, however, did not find an effect on Ca and P digestibility with lower aflatoxin levels:  Bai et al. (2014) feeding diets contaminated with 96 (starter) and 157 µg Aflatoxins (grower) per kg of feed to broilers and Han et al. (2008) saw no impact on cherry valley ducks with levels of 20 and 40 µg AFB1/kg diet.

Indirectly, a decrease in the availability of Ca and P due to aflatoxin-contaminated feed can be shown by blood or tibia levels of these minerals, as demonstrated by  Zhao et al. (2010): They conducted a trial with broilers, resulting in blood serum levels of Ca and P levels significantly (P<0.05) dropped with feed contaminated with 2 mg/kg of AFB1. Another trial conducted by Bai et al. (2014) showed decreased Ca in the tibia and reduced tibial break strength.

To get more information about the effect of mycotoxins on bone mineralization and the utilization of Ca, P, and Vit. D in animal organisms, Costanzo et al. (2015) challenged osteosarcoma cells with 5 and 50 ppb of aflatoxin B1. They asserted a significant down-modulation of the expression of the Vitamin D receptor. Furthermore, they assumed an interference of AFB1 with the actions of vitamin D on calcium-binding gene expression in the kidney and intestine.  Paneru et al. (2024) could confirm this downregulation of the Vit D receptor and additionally of the Ca and P transporters in broilers with levels of ≥75 ppb AFB1. They also saw a significant reduction in tibial bone ash content at AFB1 levels >230 ppb, a decreased trabecular bone mineral content and density at AFB1 520 ppb, and a reduced bone volume and tissue volume of the cortical bone of the femur at the level of 230 ppb (see Figure 1). They concluded that AFB1 levels of already 230 ppb contribute to bone health issues in broilers.

Figure
Figure 1: Increasing doses of AFB1 (<2 ppb – 560 ppb) deteriorate bone quality (Paneru, 2024): Cross-sectional images of femoral metaphysis with increasing AFB1 levels (left to right). The outer cortical bone is shown in light grey, and the inner trabecular bone in blue. Higher levels of AFB1 (T4 and T5) show a disruption of the trabecular bone pattern (less dense blue pattern with thinner and more fragmented bone strands and with wide spaces between the trabecular bone) (shown in white).

All experiments strongly suggest that aflatoxins harm bone homeostasis. Additional liver damage, oxidative stress, and impaired cellular processes can exacerbate bone health issues.

Trichothecenes also negatively impact bone mineralization. Depending on the mycotoxin, they may affect the gut, decreasing the absorption of Ca and P and probably provoking an imbalance in the Ca/P ratio.

For instance, when T-2 toxin was fed to Yangzhou goslings at 0.4, 0.6, and 0.8 mg/kg of diet, it decreased the Ca levels (halved at 0.8 mg/kg) and increased the P levels in the blood serum, so the Ca/P ratio decreased from the adequate ratio of 1 – 2 to 0.85, 0.66, and 0.59 (P<0.05) (Gu et al., 2023). The alterations of the Ca and P levels, the resulting decreasing Ca/P ratio, and an additional increase in alkaline phosphatase (ALP) suggest that T-2 toxin negatively impacts Ca absorption, increases ALP, and, therefore, disturbs calcification and bone development.

Other studies show that serum P levels decreased in broilers fed DON-contaminated feed with levels of only 2.5 mg/kg (Keçi et al., 2019). One reason for the lower P level is probably the lower dry matter intake, affecting Ca and P intake. Ca serum level is not typically reduced, which can be explained by the fact that Ca plays many critical physiological roles (e.g., nerve communication, blood coagulation, hormonal regulation), so the body keeps the blood levels by reducing bone mineralization. Another explanation is delivered by Li et al. (2020): After their trial with broilers, they stated that dietary P deficiency is more critical for bone development than Ca deficiency or Ca & P deficiency. The results of the trial conducted by Keçi et al. with DON (see above) were reduced bone mineralization, affected bone density, ash content, and ash density in the femur and tibiotarsus with a stronger impact on the tibiotarsus than on the femur.

In line with trichothecenes effects in Ca and P absorption, Ledoux et al. (1992) suppose that diarrhea caused by intake of fumonisins leads to malabsorption or maldigestion of vitamin D, calcium and phosphorus, having birds with rickets as a secondary effect.

Ochratoxin A (OTA) impairs kidney function, negatively affects vitamin D metabolism, reduces Ca absorption, and contributes to deteriorated bone strength (Devegowda and Ravikiran, 2009). Indications from Huff et al. (1980) show decreased tibia strength after feeding chickens OTA levels of 2, 4, and 8 µ/g, and Duff et al. (1987) report similar results also in turkey poults.

A further mycotoxin possibly contributing to leg weakness is cyclopiazonic acid produced by Aspergillus and Penicillium. This mycotoxin is known for leading to eggs with thin or visibly racked shells, indicating an impairment of calcium metabolism (Devegowda and Ravikiran, 2009). Tran et al. (2023) also showed this fact with multiple mycotoxins.

The co-occurrence of different mycotoxins in the feed – the standard in praxis – increases the risk of leg issues. A trial with broiler chickens conducted by Raju and Devegowda (2000) showed a bone ash-decreasing effect of AFB1 (300 µg/kg), OTA (2 mg/kg), and T-2 toxin (3 mg/kg), fed individually but an incomparable higher effect when fed in combination.

Impairment of bone growth – tibial dyschondroplasia (TD)

In TD, the development of long bones is impaired, and abnormal cartilage development occurs. It is frequent in broilers, with a higher incidence in males than females. It happens when the bone grows, as the soft cartilage tissue is not adequately replaced by hard bone tissue. Some mycotoxins have been related to this condition: According to Sokolović et al. (2008), actively dividing cells such as bone marrow are susceptible to T-2 toxin, including the tibial growth plates, which regulate chondrocyte formation, maturation, and turnover.

T-2 toxin: In a study with primary cultures of chicken tibial growth plate chondrocytes (GPCs) and three different concentrations of T-2 toxin (5, 50, and 500 nM), He et al. (2011) found that T-2 toxin decreased cell viability, alkaline phosphatase activity, and glutathione content (P < 0.05). Additionally, it increased the level of reactive oxygen species and malondialdehyde in a dose-dependent way, which could be partly recompensated by adding an antioxidant (N-acetyl-cysteine). They concluded that T-2 toxin inhibits the proliferation and differentiation of GPCs and contributes, therefore, to the development of TD, altering cellular homeostasis. Antioxidants may help to reduce these effects.

Gu et al. (2023) investigated the closely bodyweight-related shank length and the tibia development in Yangzhou goslings fed feed with six different levels (0 to 2.0 mg/kg) of T-2 toxin for 21 days. They determined a clear dose-dependent slowed tibial length and weight growth (p<0.05), as well as abnormal morphological structures in the tibial growth plate. As tibial growth and shank length are closely related to weight gain (Gu et al., 2023; Gao et al., 2010; Ukwu et al., 2014; Yu et al., 2022), their slowdown indicates lower growth performance.

Fumonisin B1 is also a potential cause of this kind of leg issue. Feeding 100 and 200 mg/kg to day-old turkey poults for 21 days led to the development of TD (Weibking et al., 1993). Possible explanations are the reduced viability of chondrocytes, as found by Chu et al. (1995) after 48 h of exposure, or the toxicity of FB1 to splenocytes and chondrocytes, which was shown in different primary cell cultures from chicken (Wu et al., 1995).

Bacterial chondronecrosis with osteomyelitis lameness (BCO) can be triggered by DON and FUM

BCO presents a highly critical health and welfare issue in broiler production worldwide, and it is estimated that 1-2 % of condemnations in birds at the marketing age result from this disease. What is the reason? Today’s fast-growing broilers are susceptible to stress. This enables pathogenic bacteria to compromise epithelial barriers, translocate from the gastrointestinal tract or the pulmonary system into the bloodstream, and colonize osteochondrotic microfractures in the growth plate of the long bone. This can lead to bone necrosis and subsequent lameness.

In their experiment with DON and FUM in broilers, Alharbi et al. (2024) showed that these mycotoxins reduce the gut’s barrier strength and trigger immunosuppressive effects. They used contaminations of 0.76, 1.04, 0.94, and 0.93 mg DON/kg of feed and 2.40, 3.40, 3.20, and 3.50 mg FUM/kg diet in the starter, grower, finisher, and withdrawal phases, respectively. The team observed lameness on day 35; the mycotoxin groups always showed a significantly (P<0.05) higher incidence of cumulative lameness.

The increase in uric acid leads to gout

In general, mycotoxins, which damage the kidneys and, therefore, impact the renal excretion of uric acid, are potentially a factor for gout appearance.

One of these mycotoxins is T-2 toxin. With the trial mentioned before (Yangzhou goslings, 21 days of exposure), Gu et al. (2023) showed that the highest dosage of the toxin (2.0 mg/kg) significantly increased uric acid in the blood (P<0.05), possibly leading to the deposit of uric acid crystals in the joints and to gout.

Huff et al. (1975) applied Ochratoxin to chicks at 0, 0.5, 1.0, 2.0, 4.0, and 8.0 µg/g of feed during the first three weeks of life. They found ochratoxin A as a severe nephrotoxin in young broilers as it caused damage to the kidneys with doses of 1.0 µg/g and higher. At 4.0 and 8.0 µg/g doses, uric acid increased by 38 and 48%, respectively (see Figure 2). Page et al. (1980) also reported increased uric acid after feeding 0.5 or 1.0 mg/kg of Ochratoxin A to adult white Leghorn chickens.

FigureFigure 2: Effect of Ochratoxin A on plasma uric acid (mg/100 ml) (according to Huff et al., 1975)

Foot pad lesions – a further hint of mycotoxicosis

Foot pad lesions often result from wet litter, originating from diarrhea due to harmed gut integrity. Frequently, mycotoxins impact the intestinal tract and create ideal conditions for the proliferation of diarrhea-causing microorganisms and, therefore, secondary infections. Some also negatively impact the immune defense system, allowing pathogens to settle down or aggravate existing bacterial or viral parasitic diseases. In general, mycotoxins affect the physical (intestinal cell proliferation, cell viability, cell apoptosis), chemical (mucins, AMPs), immunological, and microbial barriers of the gut, as reported by Gao et al. (2020). Here are some examples of the adverse effects of mycotoxins leading to intestinal disorders and diarrhea:

  • Mycotoxins can modulate intestinal epithelial integrity and the renewal and repair of epithelial cells, negatively impacting the intestinal barrier’s intrinsic components; for instance, DON can significantly reduce the transepithelial electrical resistance (TEER)(Grenier and Applegate, 2013). A higher permeability of the epithelium and a decreased absorption of dietary proteins can lead to higher protein in the digesta in the small intestine, which serves as a nutrient for pathogens including perfringens (Antonissen et al., 2014; Antonissen et al., 2015).
  • The application of Ochratoxin A (3 mg/kg) increased the number of S. typhimurium in the duodenum and ceca of White Leghorn chickens (Fukata et al., 1996). Another trial with broiler chicks at a concentration of 2 mg/kg aggravated the symptoms due to an infection by S. gallinarum (Gupta et al., 2005).
  • In a trial by Grenier et al., 2016, feed contaminated with DON (1.5 mg/kg), Fumonisin B (20 mg/kg), or both mycotoxins aggravated lesions caused by coccidia.
  • DON impacts the mucus layer composition by downregulating the expression of the gene coding for MUC2, as shown in a trial with human goblet cells (Pinton et al., 2015). The mucus layer prevents pathogenic bacteria in the intestinal lumen from contacting the intestinal epithelium (McGuckin et al., 2011).
  • Furthermore, DON and other mycotoxins decrease the populations of lactic acid-producing bacteria, indicating a shift in the microbial balance (Antonissen et al., 2016).
  • FB1 causes intestinal disturbances such as diarrhea, although it is poorly absorbed in the intestine. According to Bouhet and Oswald (2007), the main toxicological effect ascertained in vivo and in vitro is the accumulation of sphingoid bases associated with the depletion of complex sphingolipids. This negative impact on the sphingolipid biosynthesis pathway could explain other adverse effects, such as reduced intestinal epithelial cell viability and proliferation, modification of cytokine production, and impairment of intestinal physical barrier function.
  • T-2 toxin can disrupt the immune response, enhance the proliferation of coli in the gut, and increase its efflux (Zhang et al., 2022).

All these mycotoxins can cause foot pad lesions by impacting gut integrity or damaging the gut mucosa. They promote pathogenic organisms and, thus, provoke diarrhea and wet litter.

Mitigating the negative impact of mycotoxins on bones and feet is crucial for performance

Healthy bones and feet are essential for animal welfare and performance. Mycotoxins can be obstructive. Consequently, the first step to protecting your animals is to monitor their feed. If the analyses show the occurrence of mycotoxins at risky levels, proactive measures must be taken to mitigate the issues and ensure the health and productivity of your poultry.

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Mycotoxins pose a threat to the horse’s digestive system

Eye Of Arabian Bay Horse

Author: Judith Schmidt, Product Manager On Farm Solutions

Alarm in the gut! Horses have a susceptible digestive system that can quickly become unbalanced. Intestinal disorders in horses are usually associated with colic. Many factors can be responsible for intestinal issues. Have you ever thought about mycotoxins? What can horse owners do to support their horse´s gut health?
The equine stomach is not robust at all. Depending on their age and use, more than half of all horses suffer from stomach pain. Their digestive system is very sensitive and very different from that of other mammals: Horses cannot vomit and often suffer from severe abdominal pain, diarrhea, or cramps if they overeat or ingest spoiled feed.

The horse´s digestive system is complex and sensitive

The horse´s stomach has a relatively small capacity of around twelve to fifteen liters. Depending on the feed’s consistency and composition, it remains in the stomach for around one to five hours before it is pressed through the stomach outlet (pylorus) into the small intestine. The horse´s entire intestine is about ten times its body length.

Figure Digestive TractFigure 1: The horse’s digestive tract

The horse´s gastrointestinal tract is a complex network, reacting extremely sensitively to changes and, therefore, highly susceptible to disorders. It essentially consists of the head intestine (lips, oral cavity, teeth, and esophagus), stomach (blind pouch, fundus, and stomach outlet), small intestine (duodenum, jejunum, and ileum), and large intestine (caecum, colon and rectum). Each section plays a crucial role in the digestive process; any disruption can lead to health issues. Understanding this structure is key to maintaining a horse’s digestive health.

Digestive disorders can have various reasons

Intestinal problems in horses can stem from diverse causes, often a complex interplay of multiple factors. By understanding these causes more deeply, horse owners can be better equipped to prevent and manage these issues. In the following, we delve into several of these causes.

1.   Too long time between the feedings

Usually, a feeding break should be at most four to six hours, as, in nature, a horse is busy eating for at least 18 hours a day. In contrast to humans, who produce stomach acid only after food intake, the horse’s stomach produces gastric acid around the clock. The continuous intake of roughage, intensive chewing, and high saliva production (a horse produces 5 to 10 L of saliva per day) is, therefore, essential to protect the stomach mucosa by neutralizing excess gastric acid.

A too-long time between feedings and, therefore, no saliva production leads to an accumulation of gastric acid in the stomach. Four hours without roughage can already cause inflammation of the mucosa and probably ulcers.

2.   Excessive amounts of concentrated feed

Excessive amounts of concentrates such as wheat or rye, conditioned by less chewing activity, increase gastric acid and histamine production, and the stomach lining can be attacked. Also, in this case, the development of stomach ulcers is possible.

Furthermore, the possibly resulting hyperacidity of the organism can lead to malfunctions of the organs, the skin, and the hooves.

3.   Stress

Stress can also lead to a higher production of gastric acid and, therefore, to gastric ulcers. The horse is a flight animal.  When it is under stress, it prepares for the impending escape, and the muscles are preferably supplied with blood, resulting in a lower blood flow to the mucous membranes. Furthermore, the rising cortisone level reduces the hydrochloric acid-suppressing prostaglandin E. As a result, more stomach acid is produced, irritating the gastric mucosa.

Stress can be triggered, e.g., by transportation, competitions, training, a change of house, a new rider, unsuitable equipment, or poor posture.

4.   Dental diseases

The teeth are essential for digestion. When feed is chewed, it is broken down and mixed with saliva. Chipped teeth cannot chew well, and the feed is not sufficiently salivated or crushed, which has a detrimental effect on digestion.

For this reason, an expert vet should check the horse´s teeth at least once a year.

5.   Administration of painkillers/medication

As with humans, long-term medication administration can promote the formation of stomach ulcers. For this reason, it is essential to ensure that horses are fed a gentle diet on the stomach, especially when using oral pain therapy, and to add stomach protection if necessary.

6. Endotoxins

If pathogens such as E. coli or clostridia proliferate extremely or are killed by an antibiotic, endotoxins can be released. These toxins can cause transformation or inflammation of the gut mucosa. In drastic cases, whole areas of the mucosa can die off. 

7. Mycotoxins – the hidden danger in horse feed

Mycotoxins in plants and horse feed are a common but often unnoticed danger to horses’ health. Mycotoxins are natural, secondary metabolites of molds that have a toxic effect on humans and animals and can trigger mycotoxicosis. Contaminated feed can severely affect the horse’s health and, in the worst case, lead to death.

Over 90 % of the world´s feed production is estimated to be contaminated with at least one mycotoxin (see also Global Mycotoxin Report 2023, EW Nutrition. The intake of mycotoxins via hay, grain, silage, or compound feed can hardly be avoided. Mycotoxins are an increasing problem for all horse owners. Scientific studies show that the mycotoxins DON and ZEA are most frequently found in horse feed and, therefore, are also frequently detected in sports horses’ urine and blood samples.

Due to the highly toxic metabolic products, feed contaminated with molds can lead to severe liver and kidney diseases in horses, affect fertility, trigger colic, and promote digestive issues (diarrhea and watery stools).

Pictures ART
Mycotoxins Horses

Figure 2: Mycotoxins and their impact on horses

How to protect the horse from mycotoxins?

The first measure against the ingestion of mycotoxins is prevention. Correct pasture management and adequate barn and feed hygiene can contribute to preventing the ingestion of toxins.

However, despite the best prophylactic measures, it is impossible to prevent mycotoxin contamination of feed completely. As mycotoxins are not visible, analyzing the feed regarding mycotoxin contamination is recommended.

To protect your horse from mycotoxins, EW Nutrition developed MasterRisk, a tool for evaluating the risk of mycotoxins. Additionally, EW Nutrition has developed a complementary feed specifically for your horse´s needs in the form of granules. The sophisticated formulation of “Toxi-Pearls” is designed to bind mycotoxins and mitigate the adverse effects of mycotoxin contamination.

The pearls contain a mixture of mycotoxin binder, brewer’s yeast, and herbs:

  • The contained mycotoxin binder effectively controls the most important feed myco- and endotoxins. It additionally supports the liver and immune system and strengthens the intestinal barrier.
  • Brewer´s yeast supports the natural strength of the gastrointestinal tract. Due to its high natural content of beta-glucans and mannan-oligosaccharides (MOS), unique surface structure, and the associated high adsorption power, brewer´s yeast has a prebiotic effect on the intestinal microbiome.
  • The additional unique herbal mixture consists of the typical gastrointestinal herbs oregano, rosemary, aniseed, fennel, and cinnamon. The processed beetroot is a true all-rounder. Literature shows that it has an antioxidant effect and strengthens the immune system. It also promotes bile secretion and, therefore, supports fat digestion.

Conclusion

The horse’s digestive tract is highly sensitive and must be supported by all means. Besides failures in management, such as too long breaks between feedings or too high amounts of feed concentrate, mycotoxins present a high risk in horse nutrition. To prevent horses from intestinal issues, feed and stress management, dental care, and medication in the case of disease must be optimized. Particular attention should be paid to possible mycotoxin contamination. Effective toxin risk management, which consists of analysis, risk evaluation, and adequate toxin risk-managing products, should be implemented.




Mycotoxins in poultry – External signs can give a hint

BROILER ROMANIA

Part 2: Beak/mouth lesions

by Marisabel Caballero and Inge Heinzl, EW Nutrition

The second part of this series will focus on oral lesions as signs of mycotoxin exposure. In this segment, we will delve into the appearance and development of oral lesions, their specific locations based on the type of mycotoxin, and how toxin levels and duration of exposure impact these lesions.

A bit of history: oral lesions in poultry and their association with mycotoxin exposure

Exposure to trichothecenes, a specific group of mycotoxins that includes T-2 toxin and scirpenols- such as monoacetoxyscirpenol (MAS), diacetoxyscirpenol (DAS), and triacetoxyscirpenol, has been associated with oral lesions since the early studies related with mycotoxins:

  • After reports of toxicosis in farm animals, Bamburg’s group (1968) aimed to isolate the toxins produced by Fusarium tricintum, then considered the most toxic fungus found in moldy corn in Wisconsin (USA). Their experiments led to the discovery of the T-2 toxin, named after the strain of F. tricintum from which it was isolated. Today, we know that this fungus was wrongly identified; it was F. sporotrichioides (Marasas et al., 1984). However, the toxin remained known as T-2.
  • Wyatt’s group (1972) already described yellowish-white lesions in the oral cavity of commercial broilers in a case report from 1972. The birds also presented lesions on the feet, shanks, and heads, which raised the possibility of contact with the toxin from the litter.
  • In some of the earliest experimental works regarding T-2 toxin in poultry, Christensen (1972) noted the development of oral necrosis in turkey poults consuming increasing levels of feed invaded by tricintum; also Wyatt (1972) found a linear increase in lesion size and severity with increasing toxin concentrations of T-2 in broilers, starting with 1 ppm. He noted that oral lesions occurred without exception in all birds receiving T-2 toxin.
  • Later, Chi and co-workers (1977) tested what later were considered sub-acute levels of T-2 in broiler chickens, finding oral lesions from 0.4 ppm after 5 to 6 weeks of exposure. At higher levels, the lesions appeared after two weeks. In the same year, Speers’ group (1977) concluded that adult laying hens are more tolerant to T-2 than young chicks and also found that another mycotoxin can produce oral lesions in poultry: monoacetoxyscirpenol (MAS).
  • Fast forward, scientific research continued and the effects of T-2 and scirpenols, either alone or in combinations, on performance and oral lesions in poultry are today well known, as studied by Kubena et al. (1989), Ademoyero & Hamilton (1991), Kubena et al. (1994), Diaz et al. (1994), Brake et al. (2000), Schuhmacher-Wolz et al. (2010), Verma & Swamy (2015), Vaccari (2017), and reviewed by Sokolovic et al. (2008), Minafra et al. (2018), Puvača & Ljubojević Pelić (2023), and Vörösházi et al. (2024).

What are oral lesions and how do they develop?

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Oral lesions caused by feed contaminated by T-2 toxin or scirpenols first occur as yellow plaques that develop into raised yellowish-gray crusts with covered ulcers (Hoerr et al., 1982). They also have been described as white in color and sometimes caseous in nature, as well as round and small, pin-point-sized, or large sheets covering a wider part of the mouth (Wyatt et al., 1972; Ademoyero and Hamilton, 1991).

Under the microscope, the lesions show a fibrinous surface layer and intermediate layers with invaginations full of rods and cocci, suggesting that the surrounding microbiota quickly colonizes the lesion. Inflammation immediately ensues as Wyatt’s team (1972) found the underlying tissues filled with granular leukocytes.

Why do T-2 toxins and other trichothecenes cause such lesions?

T-2 toxin and other trichothecenes are known for their caustic nature (evidenced by studies of Chi and Mirocha, 1978; Marasas et al., 1969), and for incidents involving accidental exposure by laboratory personnel (Bamburg et al., 1968, cited in Wyatt et al., 1972).

Induction of necrosis has been proposed as the main toxicity effect based on in vitro experiments on human skin fibroblast models. The findings were a reduction of ATP production in the cell line together with disruption of mitochondrial DNA (mtDNA) but without an increase in reactive oxygen species (ROS) or activity of caspase-3 and caspase-7, which would be the case for apoptosis (Janik-Karpinsa et al., 2022). A further study (Janik-Karpinsa et al., 2023) found that T-2, on the same cell line, reduced the number of mtDNA copies, damaging several genes and hindering its function; consequently, ATP production is inhibited, and cell necrosis ensues.

Meanwhile, an inflammatory response is triggered, and the lesions are colonized by the surrounding microbial flora (Wyatt et al., 1972). Supporting this notion, Hoerr et al. (1981) observed no mouth lesions after directly administering toxins via crop gavage. Enterohepatic recirculation, facilitating the return of toxins to the oral cavity through saliva, can amplify their toxic effects (Leeson et al., 1995).

Oral lesions depend on…

…the toxin

Oral lesions vary depending on the type of toxin involved. The location of lesions is influenced by the specific mycotoxin in the feed. For instance, research by Wyatt et al. (1972) revealed that with T-2 toxin, lesions initially manifest on the hard palate and along the tongue’s margins. Over two weeks, these lesions progress to affect the lingual papillae at the tongue’s root, the underside of the tongue, and the inner side of the lower beak near the midline.

In contrast, Ademoyero and Hamilton (1991) found that scirpenols present a different pattern. A study including 4 mycotoxins at 5 different levels found, after three weeks of exposure, that the lesions caused by triacetoxyscirpenol (TAS) predominantly occurred in the angles of the mouth (53% of the birds in the study), sparing the tongue. On the other hand, diacetoxyscirpenol (DAS) primarily induces lesions inside the upper beak (shown 47% of the broilers), followed by the inside of the lower beak (in 32% of the birds). The lesion distribution for scirpentriol mirrors that of TAS, while monoacetoxyscirpenol (MAS) resembles DAS in its impact.

Chi and Mirocha (1978) conducted a comparative analysis of lesions caused by T-2 toxin and DAS (both 5 ppm). They observed that the severity of DAS-induced lesions was higher, leading to difficulties in mouth closure for some chicks due to encrustations in the mouth angles.

…the contamination level

Different findings regarding the dose dependency of the lesions are available. Wyatt et al. (1972) (Figure 1) showed a relationship between the lesion size and the toxin level. A clear relationship between the severity and incidence of lesions and the amount of T-2 toxin was also demonstrated by Chi et al. (1977) and Speers et al. (1976). This linear relationship in the case of T-2 toxin could be confirmed for the scirpenols TAS, STO, MAS, and DAS by Ademoyero and Hamilton (1991). They demonstrated a distinct dose-response relationship in a trial with the scirpenols STO, TAS (at 5 levels between 0-8 µg/g), MAS, and DAS (at 5 levels between 0-4 µg/g).

Figure 1: Effect of the inclusion rate of T-2 on the lesion size (Wyatt et al., 1972)
Figure 1: Effect of the inclusion rate of T-2 on the lesion size (Wyatt et al., 1972)

 

Sklan et al. (2001) tested T-2 toxin at more likely levels (0, 110, 530, and 1,050 ppb) in male chickens and found lesions in 90% of the chickens fed 500 ppb T-2 and in 100% of the ones fed 1,000 ppb of T-2 after 10 to 15 days; the higher dosage provoked the lesions of higher severity. When feeding 100 ppb of T-2, mild lesions appeared in 40% of the chickens after 25 and 35 days. Another group led by Sklan (2003) studied four groups of 12 one-day-old male turkey poults fed mash diets with 0 (control), 241, 485, or 982 ppb T-2 toxin for 32/33 days. Feed intake and feed efficiency were not affected, but oral lesions were apparent on day 7. The severity of the lesions plateaued after 7–15 days, and the lesion score was dose-related (see Figure 2). In the same trial, they also tested DAS (0, 223, 429, or 860 ppb) and found a similar dose relationship.

FigureFigure 2: Lesion scores in poults fed T-2 toxin at different inclusion rates and lengths of exposure (Sklan et al., 2003)

A different result is found in the trial conducted by Hoerr et al. (1982), who observed lesions 2-4 days after initiating toxin exposure (T-2 toxin and DAS; 4 and 16 ppm for 21 days) and comparable lesions when feeding 50, 100, or 300 ppm of the same toxins for 7 days. They asserted that the toxin concentration did not influence the time to onset of lesions nor their severity. Most research, however, shows a clear dose-response relation.

…the duration of exposure

On one hand, chronic exposure to low levels of toxins often requires a specific duration before noticeable effects emerge. And on the other hand, symptoms may also diminish due to hormesis, an adaptive response of the organism to moderate, intermittent stress.

With high toxin levels, lesions appear very soon after exposure. For example, Diaz et al. (1994) exposed hens to a diet containing 2 mg DAS/kg feed, finding lesions in 40% of the birds after only 48 h of exposure. Chi and Mirocha (1978) noted lesions after five days with a T-2 level of 5 ppm. At a comparable level (4 ppm), Chi et al. (1977) reported lesions emerging in the second week of exposure, with nearly 75% of chicks experiencing oral lesions by the third week. Sklan et al. (2003) saw lesions already on day 7 when feeding T-2 toxin or DAS at 1 ppm.

When testing lower levels (200 ppb), Sklan et al. (2001) found lesions after 10 days. They became more severe after 15 to 20 days and then, their severity decreased. Hoerr et al. (1982) also confirmed this by reporting that the number and size of the lesions increased until day 14 but decreased thereafter. Both studies confirm the phenomenon of hormesis.

… animal factors

In general, lesions appear with lower levels of toxins in broilers compared with layers and in layers compared with breeders. Turkeys are also less sensitive than broilers (Puvača & Ljubojević Pelić (2023).

Age also has an influence: young birds usually still have a maturing immune system, and the detoxification processes might not be entirely in place. However, their feed intake is lower and for this reason, in studies like Wang and Hogan (2019), higher impact of mycotoxins is found in older chicks.

Furthermore, additional stress factors influence the impact of mycotoxins in animals. Stress factors are cumulative and, when different factors concur, the severity of mycotoxin effects can increase.

Are oral lesions key indicators for implementing effective toxin risk management?

Oral lesions are painful for the animals, distract them from eating, and deteriorate growth performance. Often they are related with mycotoxins; however, when they appear, an investigation of different factors should take place, including mycotoxin analysis, as oral lesions may have other causes. Some of the known causes of oral lesions in poultry are also very fine feed particle size, deficiency of Vitamins A, E, B6 and Biotin, excessive levels of copper sulphate, and some parasite infections.

This article aimed to help with the differential diagnosis by providing a summary of the knowledge we have about the type and shape of the lesions related to mycotoxin contamination, which can help on a differential diagnosis. Checking the feed for mycotoxins and implementing effective toxin management helps prevent their negative effects, keeps the animals healthy, and contributes to animal welfare and, consequently, performance.

 

References

Ademoyero, Adedamola A., and Pat B. Hamilton. “Mouth Lesions in Broiler Chickens Caused by Scirpenol Mycotoxins.” Poultry Science 70, no. 10 (October 1991): 2082–89. https://doi.org/10.3382/ps.0702082.

Bamburg, J.R., N.V. Riggs, and F.M. Strong. “The Structures of Toxins from Two Strains of Fusarium Tricinctum.” Tetrahedron 24, no. 8 (January 1968): 3329–36. https://doi.org/10.1016/s0040-4020(01)92631-6.

Bamburg, J.R., N.V. Riggs, and F.M. Strong. “The Structures of Toxins from Two Strains of Fusarium Tricinctum.” Tetrahedron 24, no. 8 (January 1968): 3329–36. https://doi.org/10.1016/s0040-4020(01)92631-6.

Brake, J., P.B. Hamilton, and R.S. Kittrell. “Effects of the Trichothecene Mycotoxin Diacetoxyscirpenol on Feed Consumption, Body Weight, and Oral Lesions of Broiler Breeders.” Poultry Science 79, no. 6 (June 2000): 856–63. https://doi.org/10.1093/ps/79.6.856.

Chi, M.S., and C.J. Mirocha. “Necrotic Oral Lesions in Chickens Fed Diacetoxyscirpenol, T—2 Toxin, and Crotocin.” Poultry Science 57, no. 3 (May 1978): 807–8. https://doi.org/10.3382/ps.0570807.

Chi, M.S., C.J. Mirocha, H.J. Kurtz, G. Weaver, F. Bates, and W. Shimoda. “Subacute Toxicity of T-2 Toxin in Broiler Chicks ,.” Poultry Science 56, no. 1 (January 1977): 306–13. https://doi.org/10.3382/ps.0560306.

Christensen, C. M., R. A. Meronuck, G. H. Nelson, and J. C. Behrens. “Effects on Turkey Poults of Rations Containing Corn Invaded by            Fusarium Tricinctum            (CDA.) Sny. &amp; Hans.” Applied Microbiology 23, no. 1 (January 1972): 177–79. https://doi.org/10.1128/am.23.1.177-179.1972.

Diaz, G. J., E. J. Squires, R. J. Julian, and H. J. Boermans. “Individual and Combined Effects of T‐2 Toxin and Das in Laying Hens.” British Poultry Science 35, no. 3 (July 1994): 393–405. https://doi.org/10.1080/00071669408417704.

European Food Safety Authority. “Scientific Opinion on the Risks for Animal and Public Health Related to the Presence of T-2 and HT-2 Toxin in Food and feed1EFSA Panel on Contaminants in the Food Chain (CONTAM).” European Food Safety Authority, 2011. https://www.efsa.europa.eu/en/efsajournal/pub/2481.

Hoerr, F, W Carlton, B Yagen, and A Joffe. “Mycotoxicosis Caused by Either T-2 Toxin or Diacetoxyscirpenol in the Diet of Broiler Chickens.” Fundamental and Applied Toxicology 2, no. 3 (May 1982): 121–24. https://doi.org/10.1016/s0272-0590(82)80092-4.

Hoerr, F. J., W. W. Carlton, and B. Yagen. “Mycotoxicosis Caused by a Single Dose of T-2 Toxin or Diacetoxyscirpenol in Broiler Chickens.” Veterinary Pathology 18, no. 5 (September 1981): 652–64. https://doi.org/10.1177/030098588101800510.

Janik-Karpinska, Edyta, Michal Ceremuga, Magdalena Wieckowska, Monika Szyposzynska, Marcin Niemcewicz, Ewelina Synowiec, Tomasz Sliwinski, and Michal Bijak. “Direct T-2 Toxicity on Human Skin—Fibroblast HS68 Cell Line—in Vitro Study.” International Journal of Molecular Sciences 23, no. 9 (April 29, 2022): 4929. https://doi.org/10.3390/ijms23094929.

Janik-Karpinska, Edyta, Michal Ceremuga, Marcin Niemcewicz, Ewelina Synowiec, Tomasz Sliwiński, and Michal Bijak. “Mitochondrial Damage Induced by T-2 Mycotoxin on Human Skin—Fibroblast HS68 Cell Line.” Molecules 28, no. 5 (March 6, 2023): 2408. https://doi.org/10.3390/molecules28052408.

Kubena, L.F., R.B. Harvey, T.S. Edrington, and G.E. Rottinghaus. “Influence of Ochratoxin A and Diacetoxyscirpenol Singly and in Combination on Broiler Chickens.” Poultry Science 73, no. 3 (March 1994): 408–15. https://doi.org/10.3382/ps.0730408.

Kubena, L.F., R.B. Harvey, W.E. Huff, D.E. Corrier, T.D. Phillips, and G.E. Rottinghaus. “Influence of Ochratoxin A and T-2 Toxin Singly and in Combination on Broiler Chickens.” Poultry Science 68, no. 7 (July 1989): 867–72. https://doi.org/10.3382/ps.0680867.

Leeson, Steven, Gonzalo J. Diaz, and John D. Summers. Poultry metabolic disorders and Mycotoxins. University Books, 1995.

Marasas, W.F.O., J.R. Bamburg, E.B. Smalley, F.M. Strong, W.L. Ragland, and P.E. Degurse. “Toxic Effects on Trout, Rats, and Mice of T-2 Toxin Produced by the Fungus Fusarium Tricinctum (Cd.) Snyd. Et Hans.” Toxicology and Applied Pharmacology 15, no. 2 (September 1969): 471–82. https://doi.org/10.1016/0041-008x(69)90045-3.

Minafra, Cibele, Denise Russi Rodrigues, Isabel Cristina Mores Vaccari, Vinícius Duarte, Fabiana Ramos dos Santos, Weslane Justina da Silva, Alison Batista Vieira Silva Gouveia, Lorrayne Moraes de Paulo, Janaina Borges dos Santos, and Júlia Marixara Souza Silva. “Oral Lesions in Broilers Caused by Corn Mycotoxins: Review – Original: Lesões Orais Em Frangos de Corte Provocadas Por Micotoxinas Do Milho: Revisão.” Pubvet 12, no. 07 (July 17, 2018). https://doi.org/10.31533/pubvet.v12n7a134.1-11.

O., Marasas W F, Paul E. Nelson, and T. A. Toussoun. Toxigenic fusarium species, identity and Mycotoxicology. University Park: Pennsylvania State University Press, 1984.

Puvača, Nikola, and Dragana Ljubojević Pelić. “Problems and Mitigation Strategies of Trichothecenes Mycotoxins in Laying Hens Production.” Journal of Agronomy, Technology and Engineering Management (JATEM) 7, no. 2 (April 1, 2024): 1074–87. https://doi.org/10.55817/isad5453.

Riahi, Insaf, Virginie Marquis, Anna Maria Pérez-Vendrell, Joaquim Brufau, Enric Esteve-Garcia, and Antonio J. Ramos. “Effects of Deoxynivalenol-Contaminated Diets on Metabolic and Immunological Parameters in Broiler Chickens.” Animals 11, no. 1 (January 11, 2021): 147. https://doi.org/10.3390/ani11010147.

Schuhmacher-Wolz, Ulrike, Karin Heine, and Klaus Schneider. “Toxicity of HT-2 and T-2 Toxins.” European Food Safety Authority, 2010. https://www.efsa.europa.eu/en/supporting/pub/en-65.

Sklan, D., E. Klipper, A. Friedman, M. Shelly, and B. Makovsky. “The Effect of Chronic Feeding of Diacetoxyscirpenol, T-2 Toxin, and Aflatoxin on Performance, Health, and Antibody Production in Chicks.” Journal of Applied Poultry Research 10, no. 1 (March 2001): 79–85. https://doi.org/10.1093/japr/10.1.79.

Sklan, D., M. Shelly, B. Makovsky, A. Geyra, E. Klipper, and A. Friedman. “The Effect of Chronic Feeding of Diacetoxyscirpenol and T-2 Toxin on Performance, Health, Small Intestinal Physiology and Antibody Production in Turkey Poults.” British Poultry Science 44, no. 1 (March 2003): 46–52. https://doi.org/10.1080/0007166031000085373.

Sokolović, Marijana, Verica Garaj-Vrhovac, and Borka ŠImpraga. “T-2 Toxin: Incidence and Toxicity in Poultry.” Archives of Industrial Hygiene and Toxicology 59, no. 1 (March 1, 2008): 43–52. https://doi.org/10.2478/10004-1254-59-2008-1843.

Speers, G.M., C.J. Mirocha, C.M. Christensen, and J.C. Behrens. “Effects on Laying Hens of Feeding Corn Invaded by Two Species of Fusarium and Pure T-2 Mycotoxin ,.” Poultry Science 56, no. 1 (January 1977): 98–102. https://doi.org/10.3382/ps.0560098.

Verma, Yamini, and Madhu Swamy. “Clinico-Pathological Effect of FeedingFusarium Sporotrichioidesand t-2 Toxin Contaminated Diet in Broiler Chicken.” Indian Journal of Veterinary Pathology 39, no. 1 (2015): 58. https://doi.org/10.5958/0973-970x.2015.00013.9.

Vörösházi, Júlia, Zsuzsanna Neogrády, Gábor Mátis, and Máté Mackei. “Pathological Consequences, Metabolism and Toxic Effects of Trichothecene T-2 Toxin in Poultry.” Poultry Science 103, no. 3 (March 2024): 103471. https://doi.org/10.1016/j.psj.2024.103471.

Wyatt, R. D., B. A. Weeks, P. B. Hamilton, and H. R. Burmeister. “Severe Oral Lesions in Chickens Caused by Ingestion of Dietary Fusariotoxin T-21.” Applied Microbiology 24, no. 2 (1972): 251–57. https://doi.org/10.1128/aem.24.2.251-257.1972.

Wyatt, R. D., J. R. Harris, P. B. Hamilton, and H. R. Burmeister. “Possible Outbreaks of Fusariotoxicosis in Avians.” Avian Diseases 16, no. 5 (October 1972): 1123. https://doi.org/10.2307/1588839.




Mycotoxins in poultry – External signs can give a hint

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Part 1: Impact on Feathering

By Dr. Inge Heinzl, Editor, and Marisabel Caballero, Global Technical Manager, EW Nutrition

 

Mycotoxins are known to decrease health and performance in poultry production. Their modes of action, such as reducing protein synthesis and promoting oxidative stress and apoptosis, lead to cell destruction and lower cell replacement, affecting several organs and tissues.

When different stress factors collude, such as high temperatures and humidity, poor ventilation, high stocking density, and management events, the effects of in-feed mycotoxins can reach a higher level, which may include external signs.

The most common and recognized external sign of mycotoxicosis is mouth lesions caused by trichothecenes, which are highly associated with the presence of T-2 in the feed. However, other signs may appear, such as paleness of combs, shanks, and feet, as well as leg problems, ruffled feathers and poor feather coverage, feed passage, and abnormal feces.

In a series of articles, we want to report on external signs facilitating a differential diagnosis of mycotoxin contamination. This is necessarily followed by feed or raw material mycotoxin analysis and strategies to avoid or mitigate the effects of mycotoxin contamination in poultry production. In the first article, we will cover feathers.

A healthy plumage is crucial for growth and reproduction

Feathering is a crucial aspect of poultry health and productivity. Feathers are essential for thermoregulation, locomotion, adequate skin protection, and reproductive success, protecting hens from injury during mating. Inadequate feathering can lead to lower feed efficiency (Leeson and Walsh, 2004) as well as loss in fertility and chick production (Fisher, 2016). Mycotoxins in poultry feed can compromise feather quality in poultry production animals. This first article delves into the relationship between mycotoxins and poor feathering, exploring different mycotoxins and their mechanisms of action.

In which way do mycotoxins compromise feathering?

On the one hand, chronic mycotoxin exposure impairs the digestive process, hindering the absorption and utilization of vital nutrients essential for feather growth. This disruption can lead to malnutrition, directly impacting the quality and health of feathers. On the other hand, mycotoxins also interfere with metabolic processes critical for feather development, such as keratin synthesis (Wyatt et al., 1975;  Nguansangiam, 2004). Enzymatic pathways involved in synthesizing keratin, the protein building block of feathers, are particularly vulnerable to mycotoxin-induced disruptions. The presence of mycotoxins in feed has been associated with the manifestation of sparse feathering and the sticking out of feathers at an unnatural angle (Emous and Krimpen, 2019). In the case of multiple mycotoxins occurring in the feed, even at singularly unimportant concentrations, a negative impact on feathering is possible. Different mycotoxins have different target organs and consequences for the animal, so their ways of compromising feathering also vary. As feathering needs protein availability, all mycotoxins affecting the protein metabolism or the absorption of nutrients also impact the feathering process. Let us look at the most prominent mycotoxins.

1.   T-2 toxin

Due to climate change, T-2 toxins are on the rise. In the US, more than 50% of the tested samples contained T-2 toxin; in Europe, we found it in 31%, and in China, in 82% of the samples (EW Nutrition, 2024). The highest level was found in Europe, with 850 ppb.

Adverse effects of T-2 toxin in goslings were shown by Gu et al. (2023), who exposed the animals to 6 different levels of T-2 toxin, from 0.2 to 2.0 mg T-2 toxin/kg of feed. The goslings showed a sparse covering with short, dry, rough, curly, and gloss-free feathers on their back with dosages ≥0.8 mg/kg. When zooming on, T-2 can cause necroses of the layer of regenerative cells in the feather base, implying malformation or absence of new feathers, as well as structural damage to existing feathers on the base of the ramus and barb ridges (Hoerr et al. (1982), Leeson et al. (1995)).

The effects in feather regenerative cells are dose-dependent, as confirmed by Hoerr et al. (1982), who applied different doses of T-2 toxin (1.5, 2, 2.5, and 3 mg/kg body weight/day) to 7-day-old broilers for 14 days. Delayed feather development, especially at high dosages, was noticed, as well as malformations and opaque bands in the feathers, the latter probably caused by a segmental reduction in diameter.

Manafi et al. (2015) noticed feather malformations when broiler chickens were challenged with 0.5 ppm T-2 toxin in the feed in combination with an inoculation of 2.4×108 cfu Mycoplasma gallisepticum. When the chickens were challenged only with T-2 toxin, the feathers were ruffled, showing that a coincidence of stress factors even aggravates the symptoms.

2.   Aflatoxins

Aflatoxins, produced by certain Aspergillus species, are among the most notorious mycotoxins. Looking at test results of the last year, Aflatoxin shows incidences between 25 (USA) over 40-65% (Europe, LATAM, MEA, and SEAP) up to 84-88% (China and South Asia) with average levels up to 42 ppb in South Asia (EW Nutrition, 2023). However, more information about the concrete impact of aflatoxins on feathering is needed. They may indirectly affect feathering because they impact digestion and the utilization of nutrients or trace minerals such as zinc, which is essential for the feather construction process. Damage to the liver impacts protein metabolism, and keratin is also necessary for feather production.

In other studies, Muhammad et al. (2017) fed 5 mg AFB1/kg to Arbor Acres broilers, and the birds showed ruffled feathers. A significantly lower feather shine was noticed by Saleemi et al. (2020) when they gave the animals 300 μg AFB1/kg of feed, and the birds of Zafar et al. (2017) showed ruffled, broken, dull, and dirty feathers after six weeks of feeding an aflatoxin-contaminated diet.

3.   Ochratoxin

Ochratoxins, commonly produced by Aspergillus and Penicillium fungi, also pose a significant threat to poultry. When looking at the mycotoxin report, this mycotoxin was found in 16% (Europe) to 70% (SEAP) of the samples (EW Nutrition, 2023). Ochratoxins primarily affect feathering by compromising the structural integrity of feathers and causing delayed feathering in broilers (Leeson, 2021).

Several trials have shown the negative impact of ochratoxin on feather quality. Hassan et al. (2010) fed OTA to laying hens and saw a dose-dependent (dosages from 0 to 10 mg/kg feed) occurrence of ruffled and broken feathers in the OTA group, whereas the plumage of the control group was shiny and well-formed. Hameed et al. (2012) also realized dull feathers when feeding 0.4 and 0.8 mg OTA per kg of feed. A further dose-dependent decrease in feather quality was described by Khan et al. (2023) in broiler chicks. He injected them with dosages from 0.1 to 1.7 mg/kg body weight on day 5 of age and saw a deterioration of feather appearance (rippled feathers) in the groups with the higher dosages of 1.3 and 1.7 mg/kg. Abidin et al. (2016) observed a similar dose-dependent deterioration of the feather quality in white Leghorn cockerels when feeding 1 or 2mg OTA/kg feed.

Combinations of aflatoxins and ochratoxins were also tested. Khan et al. (2017) fed moldy feed naturally containing 56 µg OTA and 136 µg AFB1 per kg to layer hens and saw a deterioration of feather quality with increasing feeding time. Qubih (2017) noticed ruffled feathers when feeding a diet naturally contaminated with 800 ppb of OTA and 100 ppb of AFB1.

4.   Scirpenol mycotoxins

Parkhurst et al. (1992) examined the effects of different scirpenol mycotoxins. After feeding graded levels of fusarium mycotoxins to broiler chicks until three weeks of age, they discovered that the impact of scirpenols stretched across the entire feathered body parts and that the degree of feather alteration is dose-dependent. The main alteration was a frayed or even missing web on the medial side of the outer end of the feather due to poor development of the barbs, barbules, and barbicels, and the tip of the feathers became square instead of rounded—the thinner and weaker shafts of the feathers inclined to show an accentuated medial curve.

Figure Feathering Affected By Scirpenol MycotoxinsParkhurst et al. (1992)

Figure 1: Feathering affected by scirpenol mycotoxins

In their trial, Parkhurst and Hamilton realized that 15-monoacetoxyscirpenol (15-MAS) caused the most severe alterations of feathers, and they determined a minimum effective dose (MED) of 0.5 µg/g diet. The MEDs for 4,15-diacetoxyscirpenol (4,15-DAS) and 3,4,15-triacetoxyscirpenol (TAS) were higher, 2 µg/g and > 8 µg/g, respectively.

How can we enable adequate feathering in poultry?

Adequate feathering of poultry is necessary for the animal’s health and welfare and to ensure fertility and productivity. The occurrence of mycotoxins in the feed – and the probability is high! – can cause poor feathering or the development of malformed feathers.

To best equip broilers, layers, and breeders, their feed must contain all nutrients essential for healthy growth and appropriate feathering. As the risk of contamination of the feed materials is very high (see EW Nutrition’s mycotoxin report 2023), it is of crucial importance to have an efficient mycotoxin risk management in place, which includes sampling, analysis of samples, and the use of mycotoxin binders. EW Nutrition offers MasterRisk, an online tool where farmers and feed millers can feed the results of their feed analysis concerning mycotoxins and get a risk management recommendation.

In the next part of the series, we will report on beak lesions and skin paleness, two other external signs of mycotoxin contamination.

References:

Abidin, Zain ul, Muhammad Zargham Khan, Aisha Khatoon, Muhammad Kashif Saleemi, and Ahrar Khan. “Protective Effects Ofl-Carnitine upon Toxicopathological Alterations Induced by Ochratoxin A in White Leghorn Cockerels.” Toxin Reviews 35, no. 3–4 (August 22, 2016): 157–64. https://doi.org/10.1080/15569543.2016.1219374.

Emous, R. A., and M. M. Krimpen. “Effects of Nutritional Interventions on Feathering of Poultry – a Review.” Poultry Feathers and Skin: The Poultry Integument in Health and Welfare, 2019, 133–50. https://doi.org/10.1079/9781786395115.0133.

Fisher, Colin. “Feathering in Broiler Breeder Females – Aviagen.” https://aviagen.com/, 2016. http://en.aviagen.com/assets/Tech_Center/Broiler_Breeder_Tech_Articles/English/Feathering-in-Broiler-Breeeder-Females-EN-2016.pdf.

Gu, Wang, Qiang Bao, Kaiqi Weng, Jinlu Liu, Shuwen Luo, Jianzhou Chen, Zheng Li, et al. “Effects of T-2 Toxin on Growth Performance, Feather Quality, Tibia Development and Blood Parameters in Yangzhou Goslings.” Poultry Science 102, no. 2 (February 2023): 102382. https://doi.org/10.1016/j.psj.2022.102382.

Hameed, Muhammad  Raza, Muhammad Khan, Ahrar Khan, and Ijaz Javed. “Ochratoxin Induced Pathological Alterations in Broiler Chicks: Effect of Dose and Duration.” Pakistan Veterinary Journal Pakistan Veterinary Journal 8318, no. 2 (December 2012): 2074–7764.

Hassan, Zahoor-Ul, M. Zargham Khan, Ahrar Khan, and Ijaz Javed. “Pathological Responses of White Leghorn Breeder Hens Kept on Ochratoxin A Contaminated Feed.” Pakistan Veterinary Journal 30, no. 2 (2010): 118–23.

Hoerr, F. J., W. W. Carlton, and B. Yagen. “Mycotoxicosis Caused by a Single Dose of T-2 Toxin or Diacetoxyscirpenol in Broiler Chickens.” Veterinary Pathology 18, no. 5 (September 1981): 652–64. https://doi.org/10.1177/030098588101800510.

Hoerr, F.J., W.W. Carlton, B. Yagen, and A.Z. Joffe. “Mycotoxicosis Produced in Broiler Chickens by Multiple Doses of Either T‐2 Toxin or Diacetoxyscirpenol.” Avian Pathology 11, no. 3 (January 1982): 369–83. https://doi.org/10.1080/03079458208436112.

Khan, Ahrar, Muhammad Mustjab Aalim, M. Zargham Khan, M. Kashif Saleemi, Cheng He, M. Noman Naseem, and Aisha Khatoon. “Does Distillery Yeast Sludge Ameliorate Moldy Feed Toxic Effects in White Leghorn Hens?” Toxin Reviews, January 25, 2017, 1–8. https://doi.org/10.1080/15569543.2017.1278707.

Khan, Shahzad Akbar, Eiko N. Itano, Anum Urooj, and Kashif Awan. “Ochratoxin-a Induced Pathological Changes in Broiler Chicks.” Pure and Applied Biology 12, no. 4 (December 10, 2023): 1608–16. https://doi.org/10.19045/bspab.2023.120162.

Leeson, S., and T. Walsh. “Feathering in Commercial Poultry II. Factors Influencing Feather Growth and Feather Loss.” World’s Poultry Science Journal 60, no. 1 (March 1, 2004): 52–63. https://doi.org/10.1079/wps20045.

Leeson, Steve. “Effects of Nutrition on Feathering.” Poultry World, May 22, 2021. https://www.poultryworld.net/specials/effects-of-nutrition-on-feathering/.

Leeson, Steven, Gonzalo J. Diaz Gonzalez, and John D. Summers. Poultry metabolic disorders and Mycotoxins. Guelph, Ontario, Canada: University Books, 1995.

Manafi, M., N. Pirany, M. Noor Ali, M. Hedayati, S. Khalaji, and M. Yari. “Experimental Pathology of T-2 Toxicosis and Mycoplasma Infection on Performance and Hepatic Functions of Broiler Chickens.” Poultry Science 94, no. 7 (July 2015): 1483–92. https://doi.org/10.3382/ps/pev115.

Muhammad, Ishfaq, Xiaoqi Sun, He Wang, Wei Li, Xinghe Wang, Ping Cheng, Sihong Li, Xiuying Zhang, and Sattar Hamid. “Curcumin Successfully Inhibited the Computationally Identified CYP2A6 Enzyme-Mediated Bioactivation of Aflatoxin B1 in Arbor Acres Broiler.” Frontiers in Pharmacology 8 (March 21, 2017). https://doi.org/10.3389/fphar.2017.00143.

Nguansangiam, Sudarat, Subhkij Angsubhakorn, Sutatip Bhamarapravati, and Apichart Suksamrarn. The Southeast Asian J of Tropical Medicine 34, no. 4 (2004): 899–905.

Parkhurst, Carmen R., Pat B. HamiltonON, and Adedamola A. AdemoyeroERO. “Abnormal Feathering of Chicks Caused by Scirpenol Mycotoxins Differing in Degree of Acetylation.” Poultry Science 71, no. 5 (May 1992): 833–37. https://doi.org/10.3382/ps.0710833.

Qubih, T. S. “Relationship between Mycotoxicosis and Calcium during Preproduction Period in Layers.” Iraqi Journal of Veterinary Sciences 26, no. 1 (June 28, 2012): 11–14. https://doi.org/10.33899/ijvs.2012.46888.

Saleemi, M. Kashif, Kamran Ashraf, S. Tehseen Gul, M. Noman Naseem, M. Sohail Sajid, Mashkoor Mohsin, Cheng He, Muhammad Zubair, and Ahrar Khan. “Toxicopathological Effects of Feeding Aflatoxins B1 in Broilers and Its Amelioration with Indigenous Mycotoxin Binder.” Ecotoxicology and Environmental Safety 187 (January 2020): 109712. https://doi.org/10.1016/j.ecoenv.2019.109712.

Wyatt, R.D., P.B. Hamilton, and H.R. Burmeister. “Altered Feathering of Chicks Caused by T-2 Toxin.” Poultry Science 54, no. 4 (July 1975): 1042–45. https://doi.org/10.3382/ps.0541042.

Zafar, Roheena, Farhat Ali Khan, and Muhammad Zahoor. “In Vivo Amelioration of Aflatoxin B1 in Broiler Chicks by Magnetic Carbon Nanocomposite.” Pesquisa Veterinária Brasileira 37, no. 11 (November 2017): 1213–19. https://doi.org/10.1590/s0100-736×2017001100005.

 




Mycotoxins in layer and breeder feed impact hens, eggs, hatchery, and chicks

White Chickens Farm

By Marisabel Caballero, Global Technical Manager Poultry

As the planet’s climate experiences changes, new patterns affect the microbial communities colonizing crops. Recently, several areas of the planet have experienced extreme temperatures, drought, changes in the humid/dry cycles, and an increase in atmospheric carbon dioxide (1,2). As a response, the fungi affecting the crops have shifted their geographical distribution, and with this, the pattern of mycotoxin occurrence also changed. For instance, in Europe, we are looking at higher frequencies and levels of Aflatoxins (AF), Ochratoxins (OT), and Fumonisins (FUM) than ten or even five years ago (2-4).

This affects animal production, as mycotoxin challenges show increased frequency, quantity, and variety. Mainly long-living animals, such as laying hens and breeders, can have a higher risk. Moreover, mycotoxins can also be carried over to the eggs, potentially risking human health in the case of layers (table eggs) and in the case of breeder hens, hatchery performance and day-old chick (DOC) quality.

Laying hens and breeders: carryover of mycotoxins into eggs

Most mycotoxins are absorbed in the proximal part of the gastrointestinal tract (Table 1). This absorption can be high, as in the case of aflatoxins (~90%), but also very limited, as in the case of fumonisins (<1%), with a significant portion of unabsorbed toxins remaining within the lumen of the gastrointestinal tract (5).

Once mycotoxins are ingested, detoxification and excretion processes are started by the body, and at the same time, organ damage ensues. The detoxification of mycotoxins is mainly carried out by the liver (6), and their accumulation happens primarily in the liver and kidneys. However, accumulation in other tissues, such as the reproductive organs and muscles, has also been found (7-9). The detoxification process’ objective is the final excretion of the toxins, which occurs through urine, feces, and bile; often, the toxins can also reach the eggs (7-20).

Table 1: mycotoxin absorption rates for poultry and their carry-over rate into eggs

Mycotoxin Main absorption sites Absorption rate in poultry Carry-over rate into eggs
Aflatoxins Duodenum, jejunum ≈90% ≈0.55%
DON Duodenum, jejunum ≈20% ≈0.001%
Fumonisins Duodenum, jejunum ≈1% ≈0.001%
Ochratoxin Jejunum ≈40% ≈0.15%
T-2 Duodenum, jejunum ≈20% ≈0.10%
Zearalenone Small & large intestine ≈10% ≈0.30%

(Adapted from 5, 7-17, 19-21)

Table 1 shows carry-over rates of mycotoxins into eggs, resulting from diverse studies (7-10, 14, 16, 19). However, the same studies indicate that results can vary broadly due to different factors, as reviewed by Völkel and collaborators (26). This variability is related to the amount and source of contamination, way of application, period, and the possible co-occurrence of various mycotoxins or several metabolites. Other factors to consider are animal-related, such as species, breed, sex, age group, production level, and health status. Environmental and management factors can play a role in carry-over rates, and finally, detection limits and analytical procedures also influence these results. In summary, highly varying carry-over has been demonstrated, and the risk needs to be considered when animals are exposed.

Mycotoxins in breeder’s feed impact hatchery performance and day-old chick quality

When hens are exposed to mycotoxins, their effects on the intestine, liver, and kidney decrease egg production and quality (10, 14, 27), and, in the case of breeders, consequently, affect hatchery performance, DOC production, and DOC quality (28-30). The main effects of mycotoxins, when we speak about DOC production, are exerted in the gastrointestinal tract, the liver, and the kidneys, affecting embryos and young chicks:

  • Intestine and kidneys: Mycotoxins harm the intestinal epithelium and have nephrotoxic effects, affecting calcium and vitamin D3 absorption and metabolism, necessary for eggshell quality (31). Thin and fragile shells can increase embryonic mortality, lower embryonic weight gain, and hinder hatchability (32).
  • Liver: The liver plays a central role in egg production as it is responsible for vitamin D3 metabolism, the production of nutrient transporters, and the synthesis of the lipids that make up the yolk. Thus, when liver function is impaired, the internal and external quality of the egg declines, which affects DOC production (31-34).
  • Embryo and young chicks: Studies (33-38) have found how mycotoxins affect the embryos. In general, there are two possibilities: the direct one, when the mycotoxin is transferred into the egg, and the indirect one, when the mycotoxin impacts egg quality and, therefore, leads to disease or death of the embryo. The result is a higher embryonic mortality or lower DOC quality. These, among others, result from the lower transfer of antioxidants and antibodies from the hen, low viability of the chick’s immune cells, and higher bacterial contamination. A lower relative weight of the bursa of Fabricio and the thymus is often found.

Qreshi’s team (29) studied the effects on the progeny of broiler breeders consuming feed highly contaminated with AFB1, finding suppression in antibody production and macrophage function in chicks after ten days. Similar results were found by other researchers (36, 37) evaluating the effects of AF and OTA as single and combined contamination. When both mycotoxins are present in the feed, the effect on hatchability and DOC quality are synergistic.

Due to mycotoxin contamination, the reproduction and immune response are impaired, resulting in decreased DOC production and increased early chick mortality, as they are more susceptible to bacterial and viral infections.

Mycotoxins impair table egg production and quality

Studies (22-24) have found mycotoxin contamination in commercial table eggs. A meta-analysis of mycotoxins’ concentration based on 11 published papers was completed recently (22): counting with data from 9509 samples, the meta-analysis reveals an overall presence of mycotoxins in 30% of the samples, being Beauvericin in the first place, followed by DON as well as AF and OTA in third and fourth place, respectively. The risk for humans depends on the intake of contaminated foods in terms of amount and frequency (25), and so far, it has not been estimated in most parts of the world.

Natural contamination in laying hens: a case report

Giancarlo Bozzo’s team (39) reported and published a veterinary case regarding natural mycotoxin contamination in commercial egg production: up to week 47 of age, production parameters were on top of the genetic standards. However, a drop in egg production started at around week 47, and at week 50, egg production was only 68% (figure 1).

Figure
Figure 1: production of laying hens fed naturally contaminated feed with AFB1 and OTA
The house with the reduced performance received feed with linseed. In other houses of the same complex, which did not include linseed in the feed, production was unaffected. Therefore, this raw material was considered a possible cause of the issue. Linseed was removed from the formula, and three weeks after (53 weeks of age), egg production was at 84%. Afterward, linseed got back into the formulation, and the laying rate dropped again to 70% (week 56), this time accompanied by a significant increase in mortality.

Samples were collected at week 56, and AFB1 and OTA were detected in feed and the kidneys and livers of the hens consuming it (table 2). While the levels in the feed were not considered high risk, evidence from necropsy and histopathology suggested either a higher or a prolonged exposure; a synergistic effect of both mycotoxins on hen’s health and productivity can be inferred.

Table 2: mycotoxin analysis results for feed and organs

HPLC analysis results in samples of:
toxin Feed 1
(n=5)
Feed 2
(n=5)
Kidney

(n=10)

Liver

(n=10)

OTA 1.1 ± 0.1 ppb 31 ± 3 ppb 47 ± 3 ppb 24 ± 2 ppb
AFB1 ND 5.6 ± 0.3 ppb 1.4 ± 0.3 ppb 3.6 ± 0.4 ppb

The liver and kidneys were enlarged and showed signs of damage. Furthermore, urate crystals in the peritoneum and the abdominal air sac were observed, indicating renal failure. This limited the excretion of both toxins in the urine, increasing their half-life in the organism and enhancing the effects in target organs, contributing to the synergistic effect observed.

After using mycotoxin-free certified linseed, the problem receded. Though this is the best option to keep animals healthy and productive, it may not be practical in the long term due to the ubiquitous nature of the toxins and the cost and availability constraints of feed raw materials. Moreover, the mycotoxin levels present in the feed were relatively low and fell under recommended guidelines. For these reasons, in-feed toxin mitigation solutions must also be considered to reduce exposure for production animals.

In-feed intervention mitigates the effects of intermittent exposure to multiple mycotoxins

EW Nutrition conducted a study with Hy-Line W-36 layer-breeders intercalating three 10-day cycles of feed with 100ppb AFB1 + 100ppb OTA, with two 21-day cycles of non-challenged feed. An in-feed intervention (Solis Max 2.0, displayed as IFI) containing bentonite, yeast cell wall components, and a mixture of phytogenic components mitigated all effects.

Table 3: experimental groups and mycotoxin challenge

Treatment Group 100 ppb AFB1+ 100 ppb OTA IFI (2 kg/ton)
T-1 Control (C)
T-2 C+IFI X
T-3 Challenge (Ch) X
T-4 Ch+IFI X X

Trial design:

A total of 576 hens (18 replicates per diet, 8 hens each) and 58 roosters were randomly assigned to four diets at 28 weeks of age, as shown in Table 3. The 72-day experimental period included alternating 10-day challenge and 21-day non-challenge intervals (Figure 2). During the challenge intervals, the breeders in T-3 and T-4 were fed the mycotoxin-contaminated feed with and without the IFI.

FigureFigure 2: trial timeline showing challenge and non-challenge intervals and days of data collection and sampling.

Mitigated effects on egg production and egg quality

The challenge decreased overall egg production (Figure 3), egg mass, and shell thickness (Table 4). The first challenge interval did not affect production, but days later, from the first non-challenge period, all parameters were lower for the challenged group.

FigureDifferent letters indicate significant differences (p<0.05). Statistical tendencies (p<0.1) are indicated by (*).

Figure 3: Egg production of hens intermittently challenged with AFB1 and OTA, with and without in-feed Solis Max

The adverse effects on productivity and egg quality started after the first challenged feed was withdrawn and persisted through the following intervals until the end of the experiment. Similar effects in chronic mycotoxin challenges have been previously found (37, 39).

Table 4: Average egg quality parameters of hens intermittently challenged with AFB1+OTA, with and without an in-feed intervention (IFI)

Group Eggshell strength (N) Eggshell thickness (mm) Haugh Units
Control 21,02a 0,3661ab 70,88
IFI 21,16a 0,3702a 71,68
Challenge 20,05b 0,3630b   70,07*
Ch+IFI 21,06a 0,3698a 71,06

Different letters indicate significant differences (p<0.05). Statistical tendencies (p<0.1) are indicated by (*).

Mitigated effects on the progeny in incubation trials

Three incubation trials were performed: after the first challenge and non-challenge interval and at the end of the trial period after the third challenge interval. A significant decrease in fertility and hatchability was observed for the challenged group in all incubation trials. As mycotoxins affect egg quality (22-24) and can be transferred to the eggs (10, 14, 27), the effects were also shown in the case of hatchability and offspring performance. Fertility was affected from the first challenge interval onwards, continuing to be low for the challenge group until the end of the trial. However, the hatchability of fertile eggs dropped after the withdrawal of the contaminated feed and showed the lowest value during the third challenge interval.

The in-feed supplementation of Solis Max 2.0 (IFI) resulted in the consistent recovery of egg production and egg quality throughout the whole experimental period, achieving the same levels of productivity as the non-challenged control.

Figure
Letters indicate significant differences (p<0.05). Statistical tendencies (p<0.1), indicated by (*).

Figure 4: Hatchery parameters of eggs from breeders intermittently challenged with AFB1 and OTA, with and without an in-feed intervention (IFI).

Results in hatch of fertile can be related to egg quality, as the thickness of the eggshell influences the egg’s moisture loss and exchange with the environment during the incubation period. Thinner eggshells lead to higher embryo mortality (31, 32). The group having the challenge with Solis Max showed the same performance as the non-challenged control regarding hatchery performance.

Day-old chick weight was not affected. However, weight gain and mortality after ten days were hindered for the chicks from breeders taking the mycotoxin-contaminated feed (Table 5).

Table 5: Average day- and 10-day-old chick parameters from hens intermittently challenged with AFB1+OTA, with and without an in-feed intervention (IFI)

Parameter Control Challenge Ch + IFI
DOC body weight (g) 36,67 36,24 36,80
10-day body weight (g) 76,30a 75,94b 79,50a
10-day mortality (%) 0,94 1,26 0,97

Letters indicate significant differences (p<0.05). Statistical tendencies (p<0.1) indicated by (*)

At the end of the experiment, oxidative stress biomarkers were measured in the blood serum of 15 hens per treatment, showing significantly lower GPx, and SOD (figure 5) in the challenged group, which indicates a depletion of the mechanisms to fight oxidative stress (40), the hens taking the in-feed product did not show this depletion.

FigureFigure 5: Antioxidants in blood serum, glutathione peroxidase (GPx), and superoxide dismutase (SOD) from breeders intermittently challenged with AFB1 and OTA, with and without an in-feed intervention (IFI).

Intermittent exposure to AFB1 and OTA negatively affected layer breeder productivity, egg quality, and hatchability and promoted oxidative stress in the birds. Intermittent mycotoxin challenges may affect animals even after the contamination is withdrawn. In-feed interventions showed effectiveness in mitigating these effects.

Climate changes bring new mycotoxin challenges – the right in-feed solutions can help

Today’s mycotoxin scenario shows increased frequency, quantity, and variety. Mainly long-living animals, such as laying hens and breeders, can be at more risk. Additionally, the contamination can be carried over to the eggs, potentially risking human health in the case of table eggs and hatchery performance and DOC quality in the case of breeders.

From case reports, we learn the consequences of real challenges and struggles in commercial production; from scientific trials based on possible commercial situations, we realize the advantages of interventions designed to tackle those challenges.

References

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Masked mycotoxins – particularly dangerous for dairy cows

Cows

By Si-Trung Tran, SEAP Regional Technical Manager, EW Nutrition

Marisabel Caballero, Global Technical Manager Poultry, EW Nutrition, and
Inge Heinzl, Editor, EW Nutrition

Mycotoxins are secondary metabolites of fungi, commonly found as contaminants in agricultural products. In some cases, these compounds are used in medicine or industry, such as penicillin and patulin. In most cases, however, they are considered xenobiotics that are toxic to animals and humans, causing the disease collectively known as mycotoxicosis. The adverse effects of mycotoxins on human and animal health have been documented in many publications. Aflatoxins (AFs) and deoxynivalenol (DON, vomitoxin) are amongst the most critical mycotoxins affecting milk production and -quality.

Aflatoxins do not only affect cows

Aflatoxins (AFs) are highly oxygenated, heterocyclic difuranocoumarin compounds produced by Aspergillus flavus and Aspergillus parasiticus. They colonize crops, including many staple foods and feed ingredients. Within a group of over 20 AFs and derivatives, aflatoxin B1 (AFB1), B2, G1, and G2 are the most important naturally occurring compounds.

Among the aflatoxins, AFB1 is the most widespread and most toxic to humans and animals. Concern about mycotoxin contamination in dairy products began in the 1960s with the first reported cases of contamination by aflatoxin M1 (AFM1), a metabolite of AFB1 formed in the liver of animals and excreted in the milk.

There is ample evidence that lactating cows exhibit a significant reduction in feed efficiency and milk yield within a few days of consuming aflatoxin-contaminated feed. At the cellular level, aflatoxins cause degranulation of endoplasmic membranes, loss of ribosomes from the endoplasmic reticulum, loss of nuclear chromatin material, and altered nuclear shapes. The liver, as the organ mainly dealing with the decontamination of the organism, gets damaged, and performance drops. Immune cells are also affected, reducing immune competence and vaccination success (Arnold and Gaskill, 2023).

DON reduces cows’ performance

Another mycotoxin that can also reduce milk quality and affect metabolic parameters, as well as the immune function of dairy cows, is DON. DON is produced by different fungi of the Fusarium genus that infect plants. DON synthesis is associated with rainy weather from crop flowering to harvest. Whitlow and co-workers (1994) reported the association between DON and poor performance in dairy herds and showed decreased milk production in dairy cows fed 2.5 mg DON/kg. However, in cows fed 6 to 12 mg DON/kg dry matter for 10 weeks, no DON or its metabolite DOM-1 residues were detected in milk.

Masked mycotoxins hide themselves during analysis

Plants suffering from fungal infestations and thus confronted with mycotoxins convert the harmful forms of mycotoxins into less harmful or harmless ones for themselves by conjugation to sulfates, organic acids, or sugars. Conjugated mycotoxins cannot always be detected by standard analytical methods. However, in animals, these forms can be released and transformed into parent compounds by enzymes and microorganisms in the gastrointestinal tract. Thus, the feed may show a concentration of mycotoxins that is still below the limit value, but in the animal, this concentration is suddenly much higher. In dairy cows, the release of free mycotoxins from conjugates during digestion may play an important role in understanding the silent effects of mycotoxins.

Fusarium toxins, in particular, frequently occur in this “masked form”. They represent a serious health risk for animals and humans.

Aflatoxins first show up in the milk

Masked aflatoxins may also play a role in total aflatoxin contamination of feed materials. Research has harvested little information on masked aflatoxins that may be present in TMR ingredients. So far, metabolites such as Aflatoxin M2 have been identified (Righetti, 2021), which may reappear later in milk as AFM1.

DON-related symptoms without DON?

Sometimes, animals show DON-related symptoms, with low levels detected in the feed or raw materials. Besides sampling errors, this enigma could be due to conjugated or masked DON, which is structurally altered DON bound to various compounds such as glucose, fatty acids, and amino acids. These compounds escape conventional feed analysis techniques because of their modified chemical properties but can be released as their toxic precursors after acid hydrolysis.

Masked DON was first described in 1984 by Young and co-workers, who found that the DON content of yeast-fermented foods was higher than that of the contaminated wheat flour used in their production. The most plausible reason for this apparent increase was that the toxin from the wheat had been converted to a compound other than DON, which could be converted back to DON under certain conditions. Since this report, there has been much interest in conjugated or masked DON.

Silage: masked DON is a challenge for dairy producers

Silage is an essential feed for dairy cows, supporting milk production. Most silage is made from corn and other grains. The whole green plant is used, which can be infected by fungi. Since infection of corn with Fusarium spp. and subsequent DON contamination is usually a major problem in the field worldwide, a relatively high occurrence of this toxin in silage must be expected. The ensiling process may reduce the amount of Fusarium fungi, but the DON formed before ensiling is very stable.

Corn Silage

Silage samples show DON levels of concern

It is reasonable to assume that the DON biosynthesized by the fungi was metabolized by the plants to a new compound and thus masked DON. Under ensiling conditions, masked DON can be hydrolyzed, producing free DON again. Therefore, the level of free DON in the silage may not reflect the concentration measured in the plants before ensiling.

A study analyzed 50 silage samples from different farms in Ontario, Canada. Free DON was found in all samples, with levels ranging from 0.38 to 1.72 µg/g silage (unpublished data). Eighty-six percent of the samples contained DON at concentrations higher than 0.5 µg/g. Together with masked DON, it poses a potential threat to dairy cattle.

Specific hydrolysis conditions allow detection

However, in the natural ensiling process, the conditions for hydrolysis of masked DON are not optimal. The conditions that allow improved analysis of masked DON were recently described. This method detected masked DON in 32 of 50 silage samples (64%) along with free DON, increasing DON concentration by 23% in some cases (unpublished data).

Mycotoxins impact humans and animals

Aflatoxins, as well as DON, have adverse effects. In the case of DON, the impact on the animal is significant; in the case of aflatoxin, the possible long-term effects on humans are of higher relevance.

DON has more adverse effects on the animal and its performance

Unlike AFs, DON may be found in milk at low or trace concentrations. It is more associated with negative effects in the animal, altered rumen fermentation, and reduced flow of usable protein into the duodenum. For example, milk fat content was significantly reduced when cows were fed 6 µg DON/kg. However, the presence of DON also indicates that the feed probably contains other mycotoxins, such as zearalenone (ZEA) (estrogenic mycotoxin) and fusaric acid (pharmacologically active compound). All these mycotoxins may interact to cause symptoms that are different or more severe than expected, considering their individual effects. DON and related compounds also have immunosuppressive effects, resulting in increased somatic cell counts in milk. The U.S. FDA has established an action level for DON in wheat and wheat-derived products intended for cows, which is 5µg DON/g feed and the contaminated ingredient must not exceed 40% of the ration.

Aflatoxins decrease milk quality and pose a risk to humans

Aflatoxins are poorly degraded in the rumen, with aflatoxicol being the main metabolite that can be reconverted to AFB1. Most AFs are absorbed and extensively metabolized/hydrolyzed by enzymes found mainly in the liver. This results in the formation of AFM1, a part of which is conjugated to glucuronic acid and subsequently excreted in the bile. The other part enters the systemic circulation. It is either excreted in urine or milk. AFM1 appears within 12-48 hours after ingestion in cow’s milk. The excreted amount of AFM1 in milk from dairy cows usually ranges from 0.17% to 3% of the ingested AFB1. However, this carryover rate may vary from day to day and from one milking to the next in individual animals, as it is influenced by various factors, such as feeding regime, health status, individual biotransformation capacity, and, of course, by actual milk production. Carryover rates of up to 6.2% have been reported in high-yielding dairy cows producing up to 40 liters of milk per day.

In various experiments, AFM1 showed both carcinogenic and immunosuppressive effects. Accordingly, the International Agency for Research on Cancer (IARC) classified AFM1 as being in Group 2B and, thus, possibly carcinogenic in humans. The action level of 0.50 ppb and 0.05 ppb for AFM1 in milk is strictly adhered to by the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), respectively.

Trials show the high adsorption capacity of Solis Max

A trial was conducted at an independent laboratory located in Spain. The evaluation of the performance of Solis Max was executed with the following inclusion levels:

  • 0.10% equivalent to 1.0 kg of Solis Max per ton of feed
  • 0.20% equivalent to 2.0 kg of Solis Max per ton of feed

A phosphate buffer solution at pH 7 was prepared for the trial to simulate rumen conditions. Each mycotoxin was tested separately, preparing solutions with known contamination (final concentration described in the table below). The contaminated solutions were divided into 3 parts: A positive control, 0.10% Solis Max and 0.20% Solis Max. All samples were incubated at 41°C for 1 hour, centrifuged, and the supernatant was analyzed for the mycotoxin added to determine the binding efficacy. All analyses were carried out by high-performance liquid chromatography (HPLC) with standard detectors.

Mycotoxin Contamination Level (ppb)
Aflatoxin B1 800
DON 800
Fumonisin B1 2000
ZEA 1200

Results:
The higher concentration of Solis max showed a higher adsorption rate for most mycotoxins. The high dose of Solis Max adsorbed 99% of the AFB1 contamination. In the case of DON, more than 70% was bound. For fumonisin B1 and zearalenone, Solis max showed excellent binding rates of 87.7% and 78.9%, respectively (Figure 1).

FigureFigure 1: Solis Max showed a high binding capacity for the most relevant mycotoxins

Another trial was conducted at an independent laboratory serving the food and feed industry and located in Valladolid, Spain.

All tests were carried out as duplicates and using a standard liquid chromatography/mass spectrometry (LC/MS/MS) quantification. Interpretation and data analysis were carried out with the corresponding software. The used pH was 3.0, toxin concentrations and anti-mycotoxin agent application rates were set as follows (Table 1):

TableTable 1: Trial set-up testing the binding capacity of Solis Plus 2.0 for several mycotoxins in different contamination levels

Results:

Under acidic conditions (pH3), Solis Plus 2.0 effectively adsorbs the three tested mycotoxins at low and high levels. 100% binding of aflatoxin was achieved at a level of 150ppb and 98% at 1500ppb.In the case of fumonisin, 87% adsorption could be reached at 500ppb and 86 for a challenge with 5000ppb. 43% ochratoxin was adsorbed at the contamination level of 150ppb and 52% at 1500ppb.

FigureFigure 2: The adsorption capacity of Solis Plus 2.0 for three different mycotoxins at two challenge levels

Mycotoxins – Effective risk management is of paramount importance

Although the rumen microflora may be responsible for conferring some mycotoxin resistance to ruminants compared to monogastric animals, there are still effects of mycotoxins on rumen fermentation and milk quality. In addition, masked mycotoxins in feed present an additional challenge for dairy farms because they are not readily detectable by standard analyses.

Feeding dairy cows with feed contaminated with mycotoxins can lead to a reduction in milk production. Milk quality may also deteriorate due to an adverse change in milk composition and mycotoxin residues, threatening the innocuousness of dairy products. Dairy farmers should therefore have feed tested regularly, consider masked mycotoxins, and take action. EW Nutrition’s MasterRisk tool provides a risk evaluation and corresponding recommendations for the use of products that mitigate the effects of mycotoxin contamination and, in the end, guarantee the safety of all of us.

 




Toxin Mitigation 101: Essentials for Animal Production

Fusarium Mycotoxins

By Monish Raj, Assistant Manager-Technical Services, EW Nutrition
Inge Heinzl, Editor, EW Nutrition  

Mycotoxins, toxic secondary metabolites produced by fungi, are a constant and severe threat to animal production. They can contaminate grains used for animal feed and are highly stable, invisible, and resistant to high temperatures and normal feed manufacturing processes. Mycotoxin-producing fungi can be found during plant growth and in stored grains; the prevalence of fungi species depends on environmental conditions, though in grains, we find mainly three genera: Aspergillus, Penicillium, and Fusarium. The most critical mycotoxins for poultry production and the fungi that produce them are detailed in Fig 1.

FigureFigure 1: Fungi species and their mycotoxins of worldwide importance for poultry production (adapted from Bryden, 2012).

The effects of mycotoxins on the animal are manifold

When, usually, more than one mycotoxin enters the animal, they “cooperate” with each other, which means that they combine their effects in different ways. Also, not all mycotoxins have the same targets.

The synergistic effect: When 1+1 ≥3

Even at low concentrations, mycotoxins can display synergistic effects, which means that the toxicological consequences of two or more mycotoxins present in the same sample will be higher than the sum of the toxicological effects of the individual mycotoxins. So, disregarded mycotoxins can suddenly get important due to their additive or synergistic effect.

Table 1: Synergistic effects of mycotoxins in poultry

Synergistic interactions
DON ZEN T-2 DAS
FUM * * *
NIV * * *
AFL * *

Table 2: Additive effects of mycotoxins in poultry

Additive interactions
AFL T2 DAS MON
FUM + + + +
DON + +
OTA + +

Recognize the effects of mycotoxins in animals is not easy

The mode of action of mycotoxins in animals is complex and has many implications. Research so far could identify the main target organs and effects of high levels of individual mycotoxins. However, the impact of low contamination levels and interactions are not entirely understood, as they are subtle, and their identification requires diverse analytical methods and closer observation.

With regard to the gastrointestinal tract, mycotoxins can inhibit the absorption of nutrients vital for maintaining health, growth, productivity, and reproduction. The nutrients affected include amino acids, lipid-soluble vitamins (vitamins A, D, E, and K), and minerals, especially Ca and P (Devegowda and Murthy, 2005). As a result of improper absorption of nutrients, egg production, eggshell formation, fertility, and hatchability are also negatively influenced.

Most mycotoxins also have a negative impact on the immune system, causing a higher susceptibility to disease and compromising the success of vaccinations. Besides that, organs like kidneys, the liver, and lungs, but also reproduction, endocrine, and nervous systems get battered.

Mycotoxins have specific targets

Aflatoxins, fumonisins, and ochratoxin impair the liver and thus the physiological processes modulated and performed by it:

  • lipid and carbohydrate metabolism and storage
  • synthesis of functional proteins such as hormones, enzymes, and nutrient transporters
  • metabolism of proteins, vitamins, and minerals.

For trichothecenes, the gastrointestinal tract is the main target. There, they hamper digestion, absorption, and intestinal integrity. T-2 can even produce necrosis in the oral cavity and esophagus.

Figure Main Targets Of Important MycotoxinsFigure 2: Main target organs of important mycotoxins

How to reduce mycotoxicosis?

There are two main paths of action, depending on whether you are placed along the crop production, feed production, or animal production cycle. Essentially, you can either prevent the formation of mycotoxins on the plant on the field during harvest and storage or, if placed at a further point along the chain, mitigate their impact.

Preventing mycotoxin production means preventing mold growth

To minimize the production of mycotoxins, the development of molds must be inhibited already during the cultivation of the plants and later on throughout storage. For this purpose, different measures can be taken:

Selection of the suitable crop variety, good practices, and optimal harvesting conditions are half of the battle

Already before and during the production of the grains, actions can be taken to minimize mold growth as far as possible:

  • Choose varieties of grain that are area-specific and resistant to insects and fungal attacks.
  • Practice crop rotation
  • Harvest proper and timely
  • Avoid damage to kernels by maintaining the proper condition of harvesting equipment.

Optimal moisture of the grains and the best hygienic conditions are essential

The next step is storage. Here too, try to provide the best conditions.

  • Dry properly: grains should be stored at <13% of moisture
  • Control moisture: minimize chances of moisture to increase due to condensation, and rain-water leakage
  • Biosecurity: clean the bins and silos routinely.
  • Prevent mold growth: organic acids can help prevent mold growth and increase storage life.

Mold production does not mean that the war is lost

Even if molds and, therefore, mycotoxins occur, there is still the possibility to change tack with several actions. There are measures to improve feed and support the animal when it has already ingested the contaminated feed.

1.    Feed can sometimes be decontaminated

If a high level of mycotoxin contamination is detected, removing, replacing, or diluting contaminated raw materials is possible. However, this is not very practical, economically costly, and not always very effective, as many molds cannot be seen. Also, heat treatment does not have the desired effect, as mycotoxins are highly heat stable.

2.    Effects of mycotoxins can be mitigated

Even when mycotoxins are already present in raw materials or finished feed, you still can act. Adding products adsorbing the mycotoxins or mitigating the effects of mycotoxins in the organism has been considered a highly-effective measure to protect the animals (Galvano et al., 2001).

This type of mycotoxin mitigation happens at the animal production stage and consists of suppressing or reducing the absorption of mycotoxins in the animal. Suppose the mycotoxins get absorbed in the animal to a certain degree. In that case, mycotoxin mitigation agents help by promoting the excretion of mycotoxins, modifying their mode of action, or reducing their effects. As toxin-mitigating agents, the following are very common:

Aluminosilicates: inorganic compounds widely found in nature that are the most common agents used to mitigate the impact of mycotoxins in animals. Their layered (phyllosilicates) or porous (tectosilicates) structure helps “trap” mycotoxins and adsorbs them.

  • Bentonite / Montmorillonite: classified as phyllosilicate, originated from volcanic ash. This absorbent clay is known to bind multiple toxins in vivo. Incidentally, its name derives from the Benton Shale in the USA, where large formations were discovered 150 years ago.
    Bentonite mainly consists of smectite minerals, especially montmorillonite (a layered silicate with a larger surface area and laminar structure).
  • Zeolites: porous crystalline tectosilicates, consisting of aluminum, oxygen, and silicon. They have a framework structure with channels that fit cations and small molecules. The name “zeolite” means “boiling stone” in Greek, alluding to the steam this type of mineral can give off in the heat). The large pores of this material help to trap toxins.

Activated charcoal: the charcoal is “activated” when heated at very high temperatures together with gas. Afterward, it is submitted to chemical processes to remove impurities and expand the surface area. This porous, powdered, non-soluble organic compound is sometimes used as a binder, including in cases of treating acute poisoning with certain substances.

Yeast cell wall: derived from Saccharomyces cerevisiae. Yeast cell walls are widely used as adsorbing agents. Esterified glucomannan polymer extracted from the yeast cell wall was shown to bind to aflatoxin, ochratoxin, and T-2 toxin, individually and combined (Raju and Devegowda 2000).

Bacteria: In some studies, Lactic Acid Bacteria (LAB), particularly Lactobacillus rhamnosus, were found to have the ability to reduce mycotoxin contamination.

Which characteristics are crucial for an effective toxin-mitigating solution

If you are looking for an effective solution to mitigate the adverse effects of mycotoxins, you should keep some essential requirements:

  1. The product must be safe to use:
    1. safe for the feed-mill workers.
    2. does not have any adverse effect on the animal
    3. does not leave residues in the animal
    4. does not bind with nutrients in the feed.
  2. It must show the following effects:
    1. effectively adsorbs the toxins relevant to your operation.
    2. helps the animals to cope with the consequences of non-bound toxins.
  3. It must be practical to use:
    1. cost-effective
    2. easy to store and add to the feed.

Depending on

  • the challenge (one mycotoxin or several, aflatoxin or another mycotoxin),
  • the animals (short-cycle or long-living animals), and
  • the economical resources that can be invested,

different solutions are available on the market. The more cost-effective solutions mainly contain clay to adsorb the toxins. Higher-in-price products often additionally contain substances such as phytogenics supporting the animal to cope with the consequences of non-bound mycotoxins.

Solis – the cost-effective solution

In the case of contamination with only aflatoxin, the cost-effective solution Solis is recommended. Solis consists of well-selected superior silicates with high surface area due to its layered structure. Solis shows high adsorption of aflatoxin B1, which was proven in a trial:

FigureFigure 3: Binding capacity of Solis for Aflatoxin

Even at a low inclusion rate, Solis effectively binds the tested mycotoxin at a very high rate of nearly 100%. It is a high-efficient, cost-effective solution for aflatoxin contamination.

Solis Max 2.0: The effective mycotoxin solution for sustainable profitability

Solis Max 2.0 has a synergistic combination of ingredients that acts by chemi- and physisorption to prevent toxic fungal metabolites from damaging the animal’s gastrointestinal tract and entering the bloodstream.

Figure

Figure 4: Composition and effects of Solis Max 2.0

Solis Max 2.0 is suitable for more complex challenges and longer-living animals: in addition to the pure mycotoxin adsorption, Solis Max 2.0 also effectively supports the liver and, thus, the animal in its fight against mycotoxins.

In an in vitro trial, the adsorption capacity of Solis Max 2.0 for the most relevant mycotoxins was tested. For the test, the concentrations of Solis Max 2.0 in the test solutions equated to 1kg/t and 2kg/t of feed.

FigureFigure 5: Efficacy of Solis Max 2.0 against different mycotoxins relevant in poultry production

The test showed a high adsorption capacity: between 80% and 90% for Aflatoxin B1, T-2 Toxin (2kg/t), and Fumonisin B1. For OTA, DON, and Zearalenone, adsorption rates between 40% and 80% could be achieved at both concentrations (Figure 5). This test demonstrated that Solis Max 2.0 could be considered a valuable tool to mitigate the effects of mycotoxins in poultry.

Broiler trial shows improved performance in broilers

Protected and, therefore, healthier animals can use their resources for growing/laying eggs. A trial showed improved liver health and performance in broilers challenged with two different mycotoxins but supported with Solis Max 2.0.

For the trial, 480 Ross-308 broilers were divided into three groups of 160 birds each. Each group was placed in 8 pens of 20 birds in a single house. Nutrition and management were the same for all groups. If the birds were challenged, they received feed contaminated with 30 ppb of Aflatoxin B1 (AFB1) and 500 ppb of Ochratoxin Alpha (OTA).

Negative control: no challenge no mycotoxin-mitigating product
Challenged group: challenge no mycotoxin-mitigating product
Challenge + Solis Max 2.0 challenge Solis Max 2.0, 1kg/t

The body weight and FCR performance parameters were measured, as well as the blood parameters of alanine aminotransferase and aspartate aminotransferase, both related to liver damage when increased.

Concerning performance as well as liver health, the trial showed partly even better results for the challenged group fed with Solis Max 2.0 than for the negative, unchallenged control (Figures 6 and 7):

  • 6% higher body weight than the negative control and 18.5% higher body weight than the challenged group
  • 12 points and 49 points better FCR than the negative control and the challenged group, respectively
  • Lower levels of AST and ALT compared to the challenged group, showing a better liver health

The values for body weight, FCR, and AST, even better than the negative control, may be owed to the content of different gut and liver health-supporting phytomolecules.

FigureFigure 6: Better performance data due to the addition of Solis Max 2.0

FigureFigure 7: Healthier liver shown by lower values of AST and ALT

Effective toxin risk management: staying power is required

Mycotoxin mitigation requires many different approaches. Mycotoxin mitigation starts with sewing the appropriate plants and continues up to the post-ingestion moment. From various studies and field experience, we find that besides the right decisions about grain crops, storage management, and hygiene, the use of effective products which mitigate the adverse effects of mycotoxins is the most practical and effective way to maintain animals healthy and well-performing. According to Eskola and co-workers (2020), the worldwide contamination of crops with mycotoxins can be up to 80% due to the impact of climate change and the availability of sensitive technologies for analysis and detection. Using a proper mycotoxin mitigation program as a precautionary measure is, therefore, always recommended in animal production.

Toxin Risk ManagementFigure

EW Nutrition’s Toxin Risk Management Program supports farmers by offering a tool (MasterRisk) that helps identify and evaluate the risk and gives recommendations concerning using toxin solutions.




Mycotoxins affect intestinal health and productivity in broiler breeders

Header Poultry SP BR

By Han Zhanqiang, Poultry Technical Manager, EWN China

Poultry meat accounts for more than one-third of global meat production. With increasing demand levels, the industry faces several challenges. Among them is the continuous supply of day-old chicks, which is affected by various issues. Mitigation strategies should be taken to ensure the supply of good quality day-old chicks to production farms.

Fast-growing broilers versus fit breeders

The poultry industry is challenged by the broiler-breeder paradox: on the one hand, fast-growing broilers are desirable for meat production. On the other hand, the parents of these broilers have the same genetic traits, but in order to be fit for reproduction, their body weight should be controlled. Thus, feed restriction programs, considering breeder nutritional requirements, are necessary to achieve breed standards for weight, uniformity, body structure, and reproductive system development, determining the success of day-old chick production.

Mycotoxins affect breeder productivity

During the rearing period, gut health problems such as coccidiosis, necrotic enteritis, and dysbiosis affect flocks. Also during the laying period, breeder flocks are also susceptible to disturbances in gut health, especially during stressful periods, leading to reduced egg production and an increase in off-spec eggs. One measure to restrain these challenges is the strict quality control of the feed. In this context, contamination with mycotoxins is an important topic. However, due to the nature of fungal contamination and limitations of sampling procedures, mycotoxins may not be detected or may be present at levels considered low and not risky.

Existing studies on mycotoxins in breeders indicate that mycotoxins can cause varying degrees of reduction in egg production and hatchability and are also associated with increased embryonic mortality. Recent studies have shown that low levels of mycotoxins interact with other stressors and may lead to reduced productivity. These losses are often mistaken for normal breeder lot variation. However, they cause economic losses far greater than normal flock-to-flock variability.

Mycotoxins impair the functionality of the gut

Low mycotoxin levels affect gut health. Individually and in combinations, mycotoxins such as DON, FUM, and T2 can impact gut functions such as digestion, absorption, permeability, immunity, and microbial balance. This is critical in feed-restricted flocks because it decreases body weight and uniformity, and in laying animals, egg production and egg quality can be reduced. Absorption of calcium and vitamin D3, which are critical for eggshell formation, depends on gut integrity and the efficiency of digestion and absorption. These factors can be adversely affected by even low mycotoxin levels: eggshells can become thin and brittle, thereby reducing hatching eggs and increasing early embryo mortality.

Prevention is the key to success in day-old chick production, therefore:

  • avoid the use of raw materials with known mycotoxin contamination.
  • use feed additives prophylactically, especially with anti-mycotoxin and antioxidant properties.

Prevention is an alternative approach to assure health and productivity in -many times unknown- mycotoxin challenges.

Figure Effect Of MycotoxinsFigure 1: Effect of mycotoxins on eggshell quality and embryo death (Caballero, 2020)

University trial shows anti-mycotoxin product improving performance

A recent study by the University of Zagreb confirmed that long-term (13 weeks) exposure to feed contaminated with mycotoxins has an impact on egg production performance – a challenge that could be counteracted by using an anti-mycotoxin product.

The negative control (NC) was offered feed without mycotoxins. In contrast, the challenged control (CC), as well as a third group, received feed contaminated with 200ppb of T2, 100ppb of DON, and 2500ppb of FMB1. To the feed of the third group, an anti-mycotoxin feed additive (Mastersorb Gold, EW Nutrition) was given on top (CC+MG).

Figure Influence On Feed IntakeFigure 2: Influence of mycotoxins on feed intake and the effect of the anti-mycotoxin product Mastersorb Gold

Figure Cumulative Number Of EggsFigure 3: The effect of mycotoxins on the cumulative number of eggs and the compensating effect of Mastersorb Gold

Figure Cumulative Egg MassFigure 4: The impact of mycotoxins on the cumulative egg mass and the countereffect of Mastersorb Gold

As expected, the contaminated feed reduced feed intake, egg production, and egg weight (Fig. 2-4). Moreover, the liver and gut were affected which was evidenced in histopathological lesion scores of the organs: the control group had the lowest score, followed by the group fed Mastersorb Gold. The challenged group without any anti-mycotoxin product scored the highest.

Breeders are susceptible to mycotoxins and need our support

Broiler breeders and day-old chick production can be affected by long-term exposure to mycotoxins, which often exceeds the tolerance range of average flocks. To reduce or even prevent the potential impact of mycotoxins, a comprehensive management strategy is crucial. This includes responsible raw material procurement, storage, and feed processing leading to high feed quality, and the consideration of breeders’ nutrient demands. The inclusion of highly effective products to manage mycotoxin risk is an additional tool to maintain breeder performance.




Feed hygiene protects animals and humans

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By Vaibhav Gawande, Assistant Manager Technical Services, Dr. Inge Heinzl, Editor, and Marisabel Caballero, Global Technical Manager Poultry, EW Nutrition

The utility value of feed consists of the nutritional value and the quality. The first covers all characteristics concerning the essential nutrients and is important for feed formulation and the adequate supply of the animals.

Feed quality comprises all characteristics of a feed influenced by treatment, storage, conservation, hygiene, and its content of specific substances. For many factors, guidance and threshold values are available which should be met to guarantee animal health and welfare, as well as to protect public health, since some undesirable substances can be transferred to animal products such as meat, eggs, and milk.

In this article, we will focus on feed hygiene. We will talk about the consequences of low feed quality, how to understand it, its causes, and possible solutions.

What are the effects of deficient feed hygiene?

The consequences of deficient feed hygiene can be divided into two parts, impurities and spoilage.

Impurities comprise:

  • the presence of soil, sand, or dust
  • contamination with or residues of heavy metals, PCB, dioxins, pesticides, fertilizers, disinfectants, toxic plants, or banned feed ingredients

In the case of spoilage, we see:

  • degradation of organic components by the action of molds and bacteria
  • growth of pathogens such as E. coli, salmonella, etc.
  • accumulation of toxins such as mycotoxins or bacterial toxins (Hoffmann, 2021)

Bad feed hygiene can also negatively impact the feed’s nutritional value by leading to a loss of energy as well as decreasing the bioavailability of vitamins A, D3, E, K, and B1.

But, how can all signs of deficient feed hygiene be recognized? Soil, sand, and probably dust can be seen in well-taken samples and impurities can be analyzed. But is it possible to spot spoilage? In this case, agglutinated particles, rancid odor, moisture, and discoloration are indicators. Sometimes, also the temperature of the feed or ingredient increases. However, spoilage is not always obvious and an analysis of the feed can give more information about the spoilage-related organisms present. It also helps to decide if the feed is safe for the animals or not. In the case of obvious alterations, the feed should not be consumed by any animal.

Different organisms decrease feed quality and impact health

Several organisms can be responsible for a decrease in feed quality. Besides the visible pests such as rats, mice, or beetles, which can easily be noticed and combatted, there are organisms whose mastering is much more difficult. In the following part, the different harmful organisms and substances are described and solutions are presented.

Enteropathogens can cause diarrhea and production losses

In poultry, different bacteria responsible for high production losses can be transferred via the feed. The most relevant of them are Clostridium perfringens, Escherichia coli, and some strains of Salmonella.

Clostridium perfringens, the cause of necrotic enteritis

Clostridium perfringens is a Gram-positive, anaerobic bacterium that is extremely resistant to environmental influences and can survive in soil, feed, and litter for several years and even reproduce. Clostridium perfringens causes necrotic enteritis mainly in 2-16 weeks old chickens and turkeys, being more critical in 3-6 weeks old chicks.

There is a clinical and a subclinical form of necrotic enteritis. The clinical form can be detected very well due to clear symptoms and mortality rates up to 50%. The subclinical form, while harder to detect, also raises production costs due to a significant decrease in performance. The best prophylaxis against clostridia is the maintenance of gut health, including feed hygiene.

Clostridia can be found in animal by-products, as can be seen in table 1.

Sr. No. Sample details Clostridium perfringens contamination Total number of samples Positivity %
Positive Negative
1 Meat and bone meal 39 52 91 42.86
2 Soya meal 0 3 3 0
3 Rape seed meal 0 1 1 0
4 Fish meal 21 17 38 55.26
5 Layer Feed 21 71 93 22.58
6 Dry fish 5 8 13 38.46
7 De-oiled rice bran 0 2 2 0
8 Maize 0 2 2 0
9 Bone meal 13 16 29 44.83

Table 1: Isolation of Clostridium perfringens from various poultry feed ingredients in Tamil Nadu, India (Udhayavel et al., 2017)

Salmonella is harmful to animals and humans

Salmonella is a gram-negative enterobacterium and can occur in feed. There are only two species – S. enterica and S. bongori (Lin-Hui and Cheng-Hsun, 2007), but almost 2700 serotypes. The most known poultry-specific Salmonella serotypes are S. pullorum affecting chicks and S. gallinarum affecting adult birds. The other two well-known serotypes, S. enteritidis and S. typhimurium are the most economically important ones because they can also infect humans.

Salmonella enteritidis, in particular, can be transferred via table eggs to humans. The egg content can be infected vertically as a result of a colonization of the reproductive tract of the hen (De Reu, 2015). The other possibility is a horizontal infection, as some can penetrate through the eggshell from a contaminated environment or poor egg handling.

Salmonella can also be transferred through meat. However, as there are more production steps where contamination can happen (breeder and broiler farm, slaughterhouse, processing plants, food storage…), traceability is more complicated. As feed can be vector, feed hygiene is crucial.

Moreover, different studies have found that the same Salmonella types found in feed are also detected – weeks later – in poultry farms and even further in the food chain, as reviewed by Ricke and collaborators (2019). Other researches even imply that Salmonella contamination of carcasses and eggs could be significantly reduced by minimizing the incidence of Salmonella in the feed (Shirota et al., 2000).

E. coli – some are pathogenic

E. coli is a gram-negative, not acid-resistant bacterium and most strains are inhabitants of the gut flora of birds, warm-blooded animals, and humans. Only some strains cause disease. To be infectious, the bacteria must have fimbriae to attach to the gut wall or the host must have an immune deficiency, perhaps due to stress. E. coli can be transmitted via contaminated feed or water as well as by fecal-contaminated dust.

Escherichia coli infections can be found in poultry of all ages and categories and nearly everywhere in the bird. E. coli affects the navel of chicks, the reproductive organs of hens, several parts of the gut, the respiratory tract, the bones and joints, and the skin and are part of the standard control.

The feed microbiome can contribute to a balanced gut microbial community. The origins of pathogenic E. coli in a flock can also be traced to feed contamination (Stanley & Bajagai, 2022). Especially in pre-starter/starter feeds, E. coli contamination can be critical as the day-old chick’s gut is starting to be colonized. Especially in this phase, maintaining a low microbial count in feed is crucial.

Molds cause feed spoilage and reduce nutritional value

Molds contaminate grains, both in the field and during storage, and can also grow in stored feed and even in feed stored or accumulated in storage facilities in animal production farms.

The contamination of feed by molds and their rapid growth can cause heating of the feed. As molds also need nutrients, their growth results in a reduction of energy and the availability of vitamins A, D3, E, K, and B1, thus decreasing the feed’s nutritional value. This heating occurs in most feeds with a moisture content higher than 15 /16%. Additionally, mold-contaminated feed tends to be dusty and has a bad taste impacting palatability and, as a consequence, feed intake and performance.

Molds produce spores that can, when inhaled, cause chronic respiratory disease or even death if the animals are exposed to contaminated feed for a longer time. Another consequence of mold contamination is the production of mycotoxins by several mold species. These mycotoxins can affect the animal in several ways, from decreasing performance to severe disease (Esmail, 2021; Government of Manitoba, 2023).

With effective feed hygiene management, we want to stop and prevent mold growth, as well as all its negative consequences.

Prevention is better than treatment

It is clear that when the feed is spoiled, it must be removed, and animal health supporting measures should take place. However, it is better to prevent the consequences of low feed hygiene on animals. Proper harvest and adequate storage of the feed are basic measures to stop mold growth. Additionally, different tools are available to protect the animals from feed bacterial load and other risk factors.

Solutions are available to support feed hygiene

There are several solutions to fight the organisms which decrease feed quality. Some directly act against the harmful substances / pathogens, and others act indirectly, meaning that they change the environment to a non-comfortable one for the organism.

Formaldehyde and propionic acid – an unbeatable team against bacteria

A combination of formaldehyde and propionic acid is perfect to sanitize feed. Formaldehyde results in bacterial DNA and protein damage, and propionic acid is active against bacteria and molds. Together, they improve the microbiological quality of the feed and reduce the risk of secondary diseases such as necrotic enteritis or dysbiosis on the farm. In addition to the pure hygienic aspect, organic acids support digestion.

An in-vitro trial was conducted to evaluate the effect of such a combination (Formycine Gold Px) against common poultry pathogens. Poultry feed was spiked with three different bacteria, achieving very high initial contamination of 1,000,000 CFU/g per pathogen. One batch of the contaminated feed served as a control (no additive). To the other contaminated batches, 1, 2, or 4 kg of Formycine per ton of feed were added. The results (means of triplicates) are shown in figures 1 a-c.

Figure A Salmonella

Figure B E

Figure C Clostridium PerfringensFigures 1 a-c: Reduction of bacterial count due to the addition of Formycine

Formycine Gold Px significantly reduced the bacterial counts in all three cases. A clear dose-response-effect can be seen and by using 2 kg of Formycine / t of feed, pathogens could not be detected anymore in the feed.

A further trial showed the positive effects of feeding Formycine Gold Px treated feed to the animals. Also here, the feed for both groups was contaminated with 1,000,000 CFU of Clostridium/g. The feed of the control group was not treated and to the treatment group, 2 kg of Formycine per t was added.

Figure Preventive EffectFigure 2: Preventive effect of Formycine Gold Px concerning necrotic enteritis gut lesions

Figure A Daily GainFigure 3a and 3b: Performance-maintaining effect of Formycine Gold Px

The trial showed that Formycine Gold Px reduced the ingestion of the pathogen, and thus could prevent the lesions caused by necrotic enteritis (Fig. 2). The consequence of this improved gut health is a better feed conversion and higher average daily gain (Fig.3a and 3b).

Products containing formaldehyde may represent a risk for humans, however, the adequate protection equipment helps to reduce/avoid exposure.

A combination of free acids and acid salts provides optimal hygienic effects

Additionally, another blend of organic acids (Acidomix AFG) shows the best effects against representatives of relevant feed-borne pathogens in poultry. In a test, 50 µl solution containing different microorganisms (reference strains of S. enterica, E. coli, C. perfringens, C. albicans, and A. niger; concentration 105 CFU/ml, respectively) were pipetted into microdilution plates together with 50 µl of increasing concentrations of a mixture of organic acids (Acidomix) After incubation, the MIC and MBC of each pathogen were calculated.

The test results show (figure 4, Minimal Bactericidal Concentration) that 0.5% of Acidomix AFG in the medium (≙ 5kg/t of feed) is sufficient to kill S. enterica, C. albicans, and A. niger and even only 2.5kg/t in the case of E. coli. If the pathogens should only be prevented to proliferate, even a lower amount of product is requested (figure 5, Minimal Inhibitory Concentration – MIC)

Figure MbcFigure 4: MBC of Acidomix AFG against different pathogens (%)

Figure MicFigure 5: MIC of Acidomix AFG against different pathogens (%)

In addition to the direct antimicrobial effect, this product decreases the pH of the feed and reduces its buffering capacity. The combination of free acids and acid salts provides prompt and long-lasting effects.

Feed hygiene: a critical path to animal performance

Feed accounts for 65-70% of broiler and 75-80% of layer production costs. Therefore, it is essential to use the available feed to the utmost. The quality of the feed is one decisive factor for the health and performance of the animals. Proper harvesting and storage are in the hands of the farmers and the feed millers. The industry offers products to control the pathogens causing diseases and the molds producing toxins and, therefore, helps farmers save feed AND protect the health and performance of their animals.

References:

Dinev, Ivan. Diseases of Poultry: A Colour Atlas. Stara Zagora: Ceva Sante Animal, 2007.

Esmail, Salah Hamed. “Moulds and Their Effect on Animal Health and Performance.” All About Feed, June 17, 2021. https://www.allaboutfeed.net/all-about/mycotoxins/moulds-and-their-effect-on-animal-health-and-performance/.

Government of Manitoba. “Spoiled Feeds, Molds, Mycotoxins and Animal Health.” Province of Manitoba – Agriculture. Accessed March 16, 2023. https://www.gov.mb.ca/agriculture/livestock/production/beef/spoiled-feeds-molds-mycotoxins-and-animal-health.html.

Hoffmann, M. “Tierwohl Und Fütterung.” LKV Sachsen: Tierwohl und Fütterung. Sächsischer Landeskontrollverband e.V., January 25, 2021. https://www.lkvsachsen.de/fuetterungsberater/blogbeitrag/artikel/tierwohl-und-fuetterung/.

Ricke, Steven C., Kurt Richardson, and Dana K. Dittoe. “Formaldehydes in Feed and Their Potential Interaction with the Poultry Gastrointestinal Tract Microbial Community–A Review.” Frontiers in Veterinary Science 6 (2019). https://doi.org/10.3389/fvets.2019.00188.

Shirota, Kazutoshi, Hiromitsu Katoh, Toshihiro Ito, and Koichi Otsuki. “Salmonella Contamination in Commercial Layer Feed in Japan.” Journal of Veterinary Medical Science 62, no. 7 (2000): 789–91. https://doi.org/10.1292/jvms.62.789.

Stanley, Dragana, and Yadav Sharma Bajagai. “Feed Safety and the Development of Poultry Intestinal Microbiota.” Animals 12, no. 20 (2022): 2890. https://doi.org/10.3390/ani12202890.

Su, Lin-Hui, and Cheng-Hsun Chiu. “Salmonella: Clinical Importance and Evolution of Nomenclature.” Chang Gung Med J 30, no. 3 (2007): 210–19.

Udhayavel, Shanmugasundaram, Gopalakrishnamurthy Thippichettypalayam Ramasamy, Vasudevan Gowthaman, Shanmugasamy Malmarugan, and Kandasamy Senthilvel. “Occurrence of Clostridium Perfringens Contamination in Poultry Feed Ingredients: Isolation, Identification and Its Antibiotic Sensitivity Pattern.” Animal Nutrition 3, no. 3 (2017): 309–12. https://doi.org/10.1016/j.aninu.2017.05.006.