By Tingting Fan, Regional Technical Manager Poultry, EW Nutrition

Chicken coccidiosis is a common and important disease in poultry production, with an incidence of infection as high as 50-70%. The mortality rates are around 20-30% or higher in highly severe cases. In addition to losses due to mortality, producers lose money due to poor growth as well as decreased meat yield and quality. Additionally, the birds get more susceptible to secondary infections, e.g., necrotic enteritis (Moore, 2016).

The costs caused by coccidiosis in poultry are about 13 billion US $ (Blake, 2020). These costs globally divide into 1 billion costs for prophylaxis/treatment and 12 billion due to performance losses. Until now, only 5% of the prophylaxis costs have been created by natural solutions. That means that there is still a high potential to be tapped.

Natural solutions, unfortunately, are only used by a minority

For a long time, ionophores fitting the classical definition of antibiotics and chemicals were used in coccidia-fighting programs – and contributed to the development of antimicrobial resistance (Nesse et al., 2015). Nowadays, the combination with vaccination in rotation or shuttle programs has reduced this danger, but there is still potential. Meanwhile, some natural solutions are available that can be integrated into coccidiosis-fighting programs. However, producers using natural solutions are still a minority.

For thousands of years, plants have been used in human and veterinary medicine. Before the discovery of antibiotics in 1928, diseases were fought with plants. To regain the effectiveness of antibiotics, using natural solutions for prophylaxis should be once more standard, and the use of antibiotics is the treatment only for critical cases.

How does Eimeria damage broilers

The pathogenic mechanism of coccidia or Eimeria spp. is mainly the massive destruction of host intestinal cells when it reproduces, resulting in severe damage to the intestinal mucosa. On the one hand, the damaged gut wall loses its capability for effective digestion and absorption of nutrients, leading to worse feed conversion and lower weight gain.

On the other hand, this damage reduces the chicken’s immunity and paves the way for other infections, such as necrotic enteritis, and raises mortality.

Table 1:The seven most known Eimeria species in broilers and their main site of occurrence

Concerning their pathogenicity, for poultry, the Eimeria species must be ordered in the following way: E. necatrix> E. tenella > E. brunetti > E. maxima > E. acervulina > Eimeria mitis, and Eimeria praecox.

Prevention is better than treatment

Thanks to its bi-layered wall with a robust structure, the oocysts of coccidia are extremely resilient. They can survive 4 to 9 months in the litter or soil and are resistant to common disinfectants. Farm personnel and visitors are also important vectors, so good biosecurity practices can reduce the number of oocysts contaminating the premises and help prevent clinical out-brakes. Coccidiosis control in poultry should focus on “prevention” rather than “treatment”, combining biosecurity practices, feed additives, and/or vaccination.

Effective hygiene on the farm is crucial

To prevent coccidia infections, one of the most critical points is hygiene. Biosecurity practices are crucial and include cleaning and disinfection of the poultry houses and their surroundings, pest control and prevention, restriction, control, and management of the entry of personnel, visitors, vehicles, and equipment, among others.

Coccidia oocysts are ubiquitous and survive for a long time, and even effective cleaning and disinfection cannot completely remove them. After a severe outbreak, it is recommended to take drastic biosecurity measures such as flame or caustic soda disinfection to prevent further spread of the disease.

When there are birds in the house, it must be paid attention that the litter is not excessively humid. Litter moisture should be maintained around 25%; turning and replacing moist litter are the best practices to follow. For keeping the litter dry, adequate ventilation and appropriate stocking density are beneficial.

To avoid unnecessary stress and gut health issues, the birds must be fed according to their requirements with high-quality feed so that the animals build up good immunity and resilience.

Coccidiosis can be controlled with effective programs

Anticoccidial drugs were the first means of preventing and controlling coccidiosis in chickens and once achieved very good results. Since Sulfaquinoxaline was found to be effective in the 1850s, about fifty other drugs have been developed for the prevention and control of coccidiosis. Generally, the anticoccidials used for years to prevent the disease can be divided into ionophores and chemicals.

Ionophores, produced as by-products of bacterial fermentation, are technically antibiotics. The great benefits of ionophores are that they kill the parasite before it can infect the bird and thus prevent damage to the host cells. Eimeria species also take a long time to develop resistance to ionophores (Chapman, 2015). Well-established ionophores are products that contain monensin, lasalocid, salinomycin, narasin, or maduramycin; the trade names are Coban/Monensin, Avatec, Coxisstac, Monteban, and Cygro.

Chemicals, these molecules, are produced by chemical synthesis. They differ from each other and ionophores as each one has a unique mode of action against coccidia. In general, they act by interfering with one or more stages of the life cycle of Eimeria, e.g., supplying fake nutrients (Amprolium, Vit. B1) to the parasite, starving them out. The active components here are nicarbazin, amprolium, zoalene, decoquinate, clopidol, robenidine and diclazuril, and the respective trade names Nicarb, Amprol, Zoamix, Deccox, Coyden, Robenz and Clinacox. Eimeria species develop resistance to these chemical molecules; therefore, they must be used carefully and with strict planning. However, cross-resistance does not develop, making them highly valuable in rotation programs.

Vaccination against coccidiosis is accepted by many farmers as a good solution to control coccidiosis in chickens. Vaccination aims to replace resistant field strains with vaccine strains, which are sensitive to anticoccidials. Currently, commercial chicken vaccines are available in natural and attenuated strains; research to obtain safer and more efficient vaccines is also ongoing.

Non-attenuated vaccines are less expensive and make for good immunity, but as they may mildly damage the intestinal epithelium, the risk of necrotic enteritis can increase. On the contrary, attenuated strains – usually “precocious” strains with shorter reproduction cycles, cause less intestinal damage and thus have a lower risk of provoking bacterial or necrotic enteritis. The immunity is like after normal infections; however, you have a controlled epidemiology, fewer coccidiosis outbreaks, and an improved uniformity of the flock.

Phytomolecules-based natural anticoccidials saponins and tannins are natural components that can also help control coccidiosis (e.g., Pretect D, EW Nutrition GmbH). These ingredients act in different ways: the tannins improve the intestinal barrier function locally and systemically. The saponins directly impact the oocysts by preventing their growth, interacting with the cholesterol in the cell membrane (triterpenoid saponin), or hindering further sporulation and causing cell death by causing pores in the cell membrane of the parasite. Altogether, Pretect D promotes the beneficial microbial population and reduces the harmful one, improves the gut barrier function, reduces mucosal inflammation, inhibits growth and replication of Eimeria, preventing their lesions, and fosters birds’ immune response against Eimeria spp.

To prove Pretect D’s effectiveness in the reduction of coccidiosis, several trials were conducted. One of the trials was carried out in Poland with 360.000 broilers in commercial conditions. The animals were divided into ten houses, and two cycles were tested. Half of the birds served as control and received Narasin and Nicarbazin in the starter and grower I diet and salinomycin in the grower II diet. The other half also were fed Narasin and Nicarbazin in the starter and grower I diet, but Pretect D @1kg/t in grower II and 0.5kg/t in the finisher diet. The results are shown in figure 1: The application of Pretect D in the grower II and finisher diet decreased the number of oocysts in the droppings more than the application of salinomycin and, therefore, reduced the spreading of coccidiosis. In addition, the performance of the broilers receiving Pretect D was nothing short of the control’s performance showing Pretect as an optimal completion in shuttle or rotation programs (see more HERE).

Figure 1: Reduction of oocysts in the droppings by Pretect D

Managing coccidiosis without promoting antimicrobial resistance is not easy, but feasible

Coccidiosis is a challenge aggravated by our current high level of production. Tools such as ionophores, chemicals, but also vaccines, and natural products are available to fight coccidiosis. However, due to the high probability of resistance development, these tools must be used carefully and in structured programs. The phytomolecules-based product Pretect D gives the possibility to reduce antimicrobial resistance as part of programs against coccidiosis.

References upon request

By Dr. Inge Heinzl, Editor, and Dr. Ruturaj Patil, Global Product Manager – Phytogenics, EW Nutrition 

For millennia, plants have been used for medicinal purposes in human and veterinary medicine and as spices in the kitchen. Since the ban of antibiotic growth promoters in 2006 by the European Union, they also came into focus in animal nutrition. Due to their digestive, antimicrobial, and gut health-promoting characteristics, they seemed an ideal alternative to compensate for the reduced use of antibiotics in critical periods such as brooding, feed change or gut-related stress.

To optimize the benefits of phytomolecules, it is crucial that

• the phytomolecules levels are standardized for consistent results and synergy
• they show the highest stability during stringent feed processing; being often highly volatile substances, they should not get lost at high temperatures and pressure
• the phytomolecules are preferably completely released and available in the animal to achieve the best effectiveness.

First step: Standardized phytomolecules

Essential oils and other phytogenics are sourced from plants. The composition of the plants substantially depends on genetic dissimilarity within accessions, plant origin, the site conditions, such as weather, soil, community, and harvest time, but also sample drying, storage, and extraction processes (Sadeh et al., 2019; Yang et al., 2018; Ehrlinger, 2007). For example, the oil extracted from thyme can contain between 22 and 71 % of the relevant phenol thymol (Soković et al., 2009; Shabnum and Wagay, 2011; Kowalczyk et al., 2020).

Modern technology enables the production of standardized phytomolecules with the highest degree of purity and lowest possible batch-to-batch variation for high-quality products. It also offers increased environmental and economic sustainability due to reliable and cost-effective sourcing technology.

Using such highly standardized phytomolecules enables the production of phytogenic-based feed supplements of consistently high quality.

Second step: Selection of the most suitable phytomolecules

Phytomolecules have different primary characteristics. Some support digestion (Cho et al., 2006, Oetting, 2006; Hernandez, 2004); others act against pathogens (Sienkiewitz et al., 2013; Smith-Palmer et al., 1998; Özer et al., 2007) or are antioxidants (Wei and Shibamoto, 2007; Cuppett and Hall, 1998). To optimize gut health in animal production, one of the main promising mechanisms is reducing pathogens while promoting beneficial microbes. The decrease of pathogens in the gut not only decreases the risk of enteritis incidence but also eliminates the inconvenient competitors for feed.

In order to find out the best combination serving the intended purpose, a high number of different phytomolecules need to be evaluated concerning their structure, chemical properties, and biological activities first. Availability and costs of the substances are further factors to consider. With the selection of the most suitable phytomolecules, different mixtures are produced and tested for their effectiveness. Here, it is essential to concern synergistic or antagonistic effects.

For an effective and efficient blend of phytomolecules, many steps of selection and tests are necessary – and as a result, possibly only a few mixtures can meet the requirements.

Third step: Protecting the ingredients

Many phytomolecules are inherently highly volatile. So, only having a standardized content of phytogenics in the product can not ensure the full availability of phytomolecules when used through animal feed. Some parts of the ingredients might already get lost in the feed mill due to the stringent feed hygienization process followed by feed millers to reduce pathogenic load. The heating is a significant challenge for the highly-volatile components in a phytomolecule-based product. So, protecting these phytomolecules becomes imperative to guarantee that the phytomolecules put into the feed will reach the animal.

A delicate balancing act is required to ensure the availability and activity of phytomolecules at the right site in the gut. The phytomolecules must not get lost during feed processing but must also be released in the intestine. A carrier with capillary binding of the phytomolecules together with a protective coating can be one of the available effective solutions. It protects the ingredients during feed processing, and ensures the release in the animal.

Study shows excellent stability of Ventar D under challenging conditions

Ventar D is a latest generation phytomolecule-based solution for gut health optimization introduced by ​EW Nutrition, GmbH. A scientific study was conducted to compare the stability of Ventar D, in the pelleting process, with two leading phytogenics competitor feed supplements.

For this trial, feed with the different added phytogenic feed supplements had to undergo a conditioning and pelletization process. The active ingredients were analyzed before and after the pelletization process. All phytogenic feed supplements under testing were added to standard broiler feed at the producer’s recommended inclusion rate. The tests took place under conditioning times of 45, 90, and 180 seconds and pelleting temperatures of 70, 80, and 90°C (158, 176, and 194°F). After cooling, triplicate samples were collected and analyzed. The respective marker substance was analyzed through gas chromatography/mass spectrometry (GC/MS) analysis to measure the recovery rate in the finished feed. The phytomolecule content of the mash feed (before pelletization) found by the laboratory was used as a baseline and set to 100% recovery. The recovery rates of the pelleted feed were evaluated relative to this baseline.

The results are presented in figure 1. Ventar D showed the highest stability of active ingredients with recovery rates of 90% at 70°C/45 sec. or 80°C/90 sec and 84% at 90°C/180 sec. The modern production technology used for Ventar D ensures that the active ingredients are well protected throughout the pelletization process.

Figure 1: Phytomolecule stability under processing conditions, relative to mash baseline (100%)

Another trial was conducted in a feed mill in the US. For this trial, ten samples were collected from different batches of mash feed where Ventar D was added at 110g/t. Conditioning of the mash feed was at 87.8°C (190°F) for 6 minutes and 45 seconds. After the pelleting process, ten samples from the pelleted feed were collected from the continuous flow with a 5 min gap between the samplings to determine Ventar D’s recovery.

The average recovery achieved for Ventar D was 92%.

Trials show improved growth performance

Initial trials showed Ventar D’s complete release in digestion models. To examine the benefit in in-vivo conditions, Ventar D was tested in broilers at an inclusion rate of 100 g/MT.

Several in vitro studies proved the antimicrobial activity of Ventar D. One test also confirms that Ventar D could exhibit differential antimicrobial activity by having stronger activity against common enteropathogenic bacteria while sparing the beneficial ones (Heinzl, 2022). Moreover, Ventar D’s antioxidant and anti-inflammatory activity support better gut barrier functioning. Better gut health leads to higher growth performance and improved feed conversion, which could be demonstrated in several trials with broilers (figures 2 and 3). In the tests, a group fed Ventar D was compared to either a control group with no such feed supplement or groups supplied with competitor products at the recommended inclusion rates.

Compared to a negative control group, the Ventar D group consistently showed a higher average daily gain of 0.3-4.1 g (0.5-8.5 %)  and a 3-4 points better feed conversion. Compared to competitor products, Ventar D provided 1-1.7 g (2-3 %) higher average daily gain and a 3 points better /1 point higher FCR than competitors 2 and 1.

Figure 2: Average daily gain (g) – results of several trials conducted with broilers

Figure 3: FCR – results of several trials conducted with broilers

Standardization and new technologies for higher profitability

Several in vitro and in vivo studies proved that Ventar D takes “phytomolecules’ power” to the next level: Combining standardized phytomolecules and optimal active ingredient protection leads to superior product stability during feed processing. The higher amount of active ingredients arriving in the gut improves gut health and increases the production performance of the animals. Ventar D shows how we can use phytomolecules more effectively and benefit from higher farm profitability.

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Cuppett, Susan L., and Clifford A. Hall. “Antioxidant Activity of the Labiatae”. Advances in Food and Nutrition Research 42 (1998): 245–71. https://doi.org/10.1016/s1043-4526(08)60097-2.

Ehrlinger, M. “Phytogenic Additives in Animal Nutrition.” Dissertation, Veterinary Faculty of the Ludwig Maximilians University, 2007.

Heinzl, I. “Efficient Microbiome Modulation with Phytomolecules”. EW Nutrition, August 30, 2022. https://ew-nutrition.com/pushing-microbiome-in-right-direction-phytomolecules/.

Hernández, F., J. Madrid, V. García, J. Orengo, and M.D. Megías. “Influence of Two Plant Extracts on Broilers Performance, Digestibility, and Digestive Organ Size.” Poultry Science 83, no. 2 (2004): 169–74. https://doi.org/10.1093/ps/83.2.169.

Kowalczyk, Adam, Martyna Przychodna, Sylwia Sopata, Agnieszka Bodalska, and Izabela Fecka. “Thymol and Thyme Essential Oil—New Insights into Selected Therapeutic Applications.” Molecules 25, no. 18 (2020): 4125. https://doi.org/10.3390/molecules25184125.

Lindner, , U. “Aromatic Plants – Cultivation and Use.” Düsseldorf: Teaching and Research Institute for Horticulture Auweiler-Friesdorf, 1987.

Oetting, Liliana Lotufo, Carlos Eduardo Utiyama, Pedro Agostinho Giani, Urbano dos Ruiz, and Valdomiro Shigueru Miyada. “Efeitos De Extratos Vegetais e Antimicrobianos Sobre a Digestibilidade Aparente, O Desempenho, a Morfometria Dos Órgãos e a Histologia Intestinal De Leitões Recém-Desmamados.” Revista Brasileira de Zootecnia 35, no. 4 (2006): 1389–97. https://doi.org/10.1590/s1516-35982006000500019.

Sadeh, Dganit, Nadav Nitzan, David Chaimovitsh, Alona Shachter, Murad Ghanim, and Nativ Dudai. “Interactive Effects of Genotype, Seasonality and Extraction Method on Chemical Compositions and Yield of Essential Oil from Rosemary (Rosmarinus Officinalis L”.).” Industrial Crops and Products 138 (2019): 111419. https://doi.org/10.1016/j.indcrop.2019.05.068.

Shabnum, Shazia, and Muzafar G. Wagay. “Essential Oil Composition of Thymus Vulgaris L. and Their Uses”. Journal of Research & Development 11 (2011): 83–94.

Sienkiewicz, Monika, Monika Łysakowska, Marta Pastuszka, Wojciech Bienias, and Edward Kowalczyk. “The Potential of Use Basil and Rosemary Essential Oils as Effective Antibacterial Agents.” Molecules 18, no. 8 (2013): 9334–51. https://doi.org/10.3390/molecules18089334.

Smith-Palmer, A., J. Stewart, and L. Fyfe. “Antimicrobial Properties of Plant Essential Oils and Essences against Five Important Food-Borne Pathogens”. Letters in Applied Microbiology 26, no. 2 (1998): 118–22. https://doi.org/10.1046/j.1472-765x.1998.00303.x.

Soković, Marina, Jelena Vukojević, Petar Marin, Dejan Brkić, Vlatka Vajs, and Leo Van Griensven. “Chemical Composition of Essential Oils of Thymus and Mentha Species and Their Antifungal Activities”. Molecules 14, no. 1 (2009): 238–49. https://doi.org/10.3390/molecules14010238.

Wei, Alfreda, and Takayuki Shibamoto. “Antioxidant Activities and Volatile Constituents of Various Essential Oils.” Journal of Agricultural and Food Chemistry 55, no. 5 (2007): 1737–42. https://doi.org/10.1021/jf062959x.

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by Dr. Inge Heinzl, Editor

From day 1, young animals are confronted with the pathogens of their environment. Feed and feed ingredients also significantly increase exposure to microbes. This article will look closely at three critical bacteria in poultry production. The trials of phytomolecules-based products shared in this article prove the unique benefit of lowering harmful pathogens while simultaneously sparing health-promoting microbes. The targeted selection of the blend’s phytomolecules contributes to this distinctive mode of action.

E. coli can be valuable… and dangerous

E.coli are commensal bacteria that usually belong to the natural gut flora. However, there are several E. coli strains that, due to certain virulence factors, can cause disease. These bacteria are called avian pathogenic E. coli or APEC. The disease ‘Colibacillosis’ can occur in different forms:

• Omphalitis – a noncontagious infection of the navel and/or yolk sac in young poultry
• peritonitis – inflammatory response on “internal laying” (yolk material in the peritoneum)
• salpingitis – inflammation of the oviduct
• cellulitis – discoloration and thickening of the skin, inflammation of the subcutaneous tissues
• synovitis – lameness with swollen joints
• coligranuloma (Hjärre disease) – lesions similar to tuberculosis, not of economic importance
• meningitis, and
• septicemia or blood poisoning.

Since some of the E. coli strains can sometimes be transmitted vertically to offspring, it is crucial to keep the pathogenic pressure in the parent generation as low as possible (Mc Dougal, 2018).

Due to the, mostly in young chicks, common use of antibiotics, E. coli strains resistant to ß-lactam antibiotics (ESBL-producing E. coli) or fluoroquinolones (e.g., Enrofloxacin) have developed.

Clostridium perfringens: the cause of necrotic enteritis

Clostridium perfringens belong to the normal caecal flora. However, its overgrowth in the intestine is linked to necrotic enteritis, causing estimated losses of up to USD 6 billion yearly in global poultry production, which corresponds to USD 0.0625 per bird (Wade and Keyburn, 2015). Necrotic enteritis can occur in a clinical and a subclinical form.

In the case of clinical necrotic enteritis, the birds suffer from diarrhea resulting in wet litter and increased flock mortality of up to 1 % per day (Ducatelle and Van Immerseel, 2010). Mortality rates sometimes sum up to 50 % (Van der Sluis, 2013). If birds die without clinical signs, it may be peracute necrotic enteritis.

The subclinical version, however, is more critical. Due to the lack of symptoms, it often remains undetected and, therefore, not treated. Mainly through the impaired utilization of feed, representing 65-75 % of the total costs in broiler production, subclinical necrotic enteritis permanently impacts production efficiency (Heinzl et al., 2020).

Salmonella enterica: a zoonosis relevant for birds and humans

Most concerning in (non-typhoid) salmonellosis is that it can be transferred to humans. The transmission occurs via direct contact with an infected animal, consuming contaminated animal products such as meat or eggs, contact with infected vectors (insects or pets) or contaminated equipment, or cross-contamination in the kitchen. Frozen or raw chicken products, as well as the eggs, are frequent causes of animal-origin Salmonella infections in humans.

Salmonella is the more critical the younger the birds. If the hatching eggs already carry salmonellae, the hatchability dwindles. During their first weeks of life, infected chicks show higher mortality and systemic infections.

Adult animals usually do not die from salmonellosis; often, the infection remains unnoticed. During an acute salmonella outbreak, the animals might show weakness and diarrhea. They lose weight, resulting in decreased egg production in layers.

Trials with phytomolecules show promising results

To check if phytomolecules-based products can effectively influence gut flora, a product specially designed for gut health (Ventar D) was tested for its antimicrobial activity. Additionally, the extent to which the same blend impacted the beneficial bacteria, such as Lactobacilli, was evaluated.

Trial 1: phytomolecules act against E. coli and Salmonella enterica

The in vitro study using the agar dilution method was conducted at a German laboratory.

The bacteria (Salmonella typhimurium and ESBL-producing E. coli) stored at -80°C were reactivated by cultivating them on Agar Mueller Hinton overnight. After this incubation, some colonies were picked and suspended in 1 ml 0.9% NaCl solution. 100 µl of the suspension were pipetted and evenly spread (plate spread technique) on new Agar Mueller Hinton containing different concentrations of a phytomolecules-based product (Ventar D): 0 µg/mL – control; 500 µg/mL; 900 µg/mL; 1.250 µg/mL and 2.500 µg/mL. After 16-20 h incubation at 37°C, growth was evaluated. The results can be seen in pictures 1 and 2:

Figure 1: E. coli exposed to different concentrations of Ventar D (upper row from left to right: control 0 µg/ml, 500 µg/ml, 900 µg/ml; lower row from left to right: 1250 µg/ml and 2500 µg/ml)

E. coli colonies exposed to 900 µg/mL of Ventar D’s phytogenic formulation were smaller than the control colonies. At 1250 µg/mL, fewer colonies were detected, and at 2500 µg/mL, growth couldn’t be seen anymore.

The salmonella colonies showed a similar picture; however, the reduction could be seen from a concentration of 1.250 µg/ml of Ventar D onwards (picture 2).

Figure 2: Salmonella enterica exposed to different concentrations of Ventar D (upper row from left to right: control 0 µg/ml, 500 µg/ml, 900 µg/ml; lower row from left to right: 1250 µg/ml and 2500 µg/ml)

Trial 2: Phytomolecules inhibit Clostridium perfringens and spare Lactobacilli

In this trial, the bacteria (Clostridium perfringens, Lactobacillus agilis S73, and Lactobacillus plantarum) were cultured under favorable conditions (RCM, 37°C, anaerobe for Clostr. perfr., and MRS, 37°C, 5 % CO₂ for Lactobacilli) and exposed to different concentrations of Ventar D (0 µg/ml – control, 500 µg/ml, 750 µg/ml, and 1000 µg/ml).

The results are shown in figures 3a-d.

In the case of Clostridium perfringens, a significant reduction of colonies could already be observed at a concentration of 500 µg/ml of Ventar D. At 750 µg/ml, only a few colonies remained. At a Ventar D concentration of 1000 µg/ml, Clostridium perfringens could no longer grow.

In contrast to Clostridium, the Lactobacilli showed a different picture: only at the higher concentration (1250 µg/ml of Ventar D), Lactobacillus plantarum and Lactobacillus agilis S73 showed a slight growth reduction (figures 4 and 5).

Figure 4: Lactobacillus plantarum exposed to 0 (left) and 1250 µg/ml (right) of Ventar D

Figure 5: Lactobacillus agilis S73 exposed to 0 (left) and 1250 µg/ml (right) of Ventar D

Improve gut health by positively influencing the intestinal flora

The experiments show that even at lower concentrations, phytomolecules impair the growth of harmful bacteria while sparing the beneficial ones. Phytomolecule-based products can be regarded as a valuable tool for controlling relevant pathogens in poultry and influencing the microflora composition in a positive way.

The resulting better gut health is the best precondition to reducing antibiotics in animal production.

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

Careful management of the breeders is a must to get their best reproductive efficiency. In today’s hatching egg production, factors such as stress, inflammation, body weight, and altered mating behavior lead to decreased performance, meaning fewer hatchable eggs and, therefore, fewer day-old chicks per hen (Grandhaye, 2020). The use of antibiotics to increase performance in farm animals is no longer allowed in many countries, and, since it may lead to the development of resistance, it is also not recommended. So, also in breeders, alternatives are requested to maintain animal health, welfare, and a high level of performance. 

Optimal gut health is the cornerstone for breeder performance 

As the organ responsible for digestion of the incoming feed, the absorption of nutrients, and the defense of the organism against pathogens or toxins, a healthy gut is a pre-condition for optimal performance (Shini and Bryden, 2021). A healthy gut, according to Bailey (2018), has optimally developed gut tissues, a well-functioning gut immune system, and well-balanced gut microbiota. It shows efficient functionality in terms of digestion and absorption and protects the organism against harmful agents. 

The gut directly or indirectly provides the elements for egg production 

Efficient feed digestion and absorption of nutrients are essential for the breeder hen to obtain the “material” for maintenance, growth, and egg production. Gut health is crucial since dysbacteriosis and diarrhea, characteristics of gut health challenges, increase dirty eggs, creating favorable conditions for pathogens to enter the egg and infect the embryo. 

Egg yolks consist of water (70%), proteins (10%), and lipids (20%). The yolk lipids are lipoproteins rich in triglycerides, built up in the liver and transported to the ovary. Cholesterol carried via lipoproteins to the egg yolk is also built up there, thus showing the importance of the liver in egg production. The gut plays a crucial role in protecting the liver from damage, constituting a barrier against harmful pathogens and toxins, potentially passing into the bloodstream and reaching this vital organ.  

Phytomolecules support performance in different ways 

Phytomolecules, are an excellent tool to support gut health and animal performance. Phytomolecules are plant-derived secondary metabolites that exert insect-attracting or defensive functions in the plant. They are used in their natural but also nature-identical forms in humans and animals to exert their digestive, immune-modulating, antimicrobial effects. 

Phytomolecules support gut health by balancing the gut microbiome 

Diverse examples can be found in the scientific literature, where phytomolecules improve the gut microbiome, resulting in better performance of layer and breeder hens. This support happens in two ways: 

1. Promoting beneficial bacteria

   Rabelo-Ruiz and co-workers (2021), asserted that adding garlic and onion extracts to the diet of layers led to more eggs with a bigger size, accompanied by an increase in Lactococci in the ileum and Lactobacilli in the cecum. Another example is provided by Park et al. (2016). When supplementing the diet of layers with a fermented phytogenic feed additive, egg production and weight raised with increasing dosage of the additive, and a higher number of Lactobacilli could be observed in the cecum.  
   Phytomolecules can promote the growth of certain beneficial bacteria and therefore act like prebiotics. As these changes took place in the lower gut, they assumed an improved digestibility of the feed. 

2. Lowering pathogenic bacteria

   In the study by Park et al. (2016) and in an in vitro study by Ghazanfari et al. (2019), E. coli in the cecum was reduced.  

   According to Burt (2007b), several essential oils / phytomolecules, amongst them, carvacrol, thymol, eugenol, and cinnamaldehyde, are effective against pathogens such as Listeria, Salmonella, E. coli, Shigella, and Staphylococcus. The hydrophobic essential oils can partition the lipids of the cell membranes. The resulting permeability of the membrane enables the leakage of cell content.  

3. Changing virulence factors

   Another mode of action is the change of virulence factors. Carvacrol, e.g., is known to decrease the motility of Campylobacter jejuni (Van Alphen et al., 2012); oregano and thyme oil reduced the motility of E. coli by inhibiting the synthesis of flagellin (Burt, 2007a). Vidanarachchi et al. (2005) mentioned that the hydrophobicity of microbes increases when some plant extracts are present, affecting their virulence characteristics. Also, the inhibition of defense measures such as efflux pumps in Gram-negative bacteria has been researched (Savoia, 2012). 

Phytomolecules support gut health by improving digestion 

For many years, phytomolecules have been studied and known for their digestive characteristics. In poultry and other animals, they influence feed digestion in two main ways. 

1. Stimulating enzyme secretion

   Platel and Srinivasan (2004) described different spices promoting not only the salivary flow, gastric juice and bile secretion but also the stimulation of the activity of enzymes such as pancreatic lipase, amylase, and proteases in rats. Hashemipour et al. (2013) saw the same effect in broilers supplemented with carvacrol and thymol in the diet. Research has also concluded on a higher nutrient digestibility:  Hernandez et al. (2004) and Basmacioğlu Malayoğlu, 2010 noticed that supplementing plant extracts or essential oils improved apparent whole-tract and ileal digestibility of different nutrients.). 

2. Maintaining gut integrity and enlarging the digestion area

   An intact gut with a large area for digestion guarantees optimal utilization of nutrients. Different researchers found that adding plant extracts or essential oils (Khalaji et al., 2011; Ghazanfari et al., 2015; Chowdhury et al., 2018) promotes intestinal gut morphology, reflected in higher villi and deeper crypts, which might lead to higher nutrient absorption.

   Concerning gut integrity, thymol and carvacrol showed protecting effects and mitigated gut lesions in broilers challenged with C. perfringens (Du et al., 2016). Probably, the lower pathogenic pressure due to the antimicrobial activity of phytogenic substances leads to minor damage to the gut wall and, in the end, to better absorption of the nutrients.  

Phytomolecules mitigate the effects of stress 

Environmental stress in breeders may decrease performance: the heat-stress-induced disruption of the tight junctions often leads to higher gut permeability, poor nutrient absorption, and higher electrolyte and water secretion (Abdelli, 2021). Sahin et al. (2010) achieved a linear improvement in egg production in quails when applying two doses of green tea catechin.  

Cold-stressed layers also reacted positively to supplementation of oregano essential oil, improving egg production compared to a non-supplemented control (Migliorini, 2019). 

Positive influence of phytomolecules results in higher performance 

As described, phytomolecules improve gut health and support the animal in multiply ways, allowing better utilization of resources for growth and production. Literature provides many articles showing the promoting effects of these substances on the performance of layers or breeders, some of them summarized in Table 1.  

Table 1: Benefits of phytomolecules in layers and breeders 

In-feed and in-water phytomolecules-based products show efficacy 

Much of the research done with phytomolecules focuses on essential oils (with variable inclusions of the active compounds or on single plant extracts. EW Nutrition is a research-driven company proposing phytomolecule-based solutions for the animal production industry. These products combine selected, synergistically acting phytomolecules to achieve optimal results.   

EW Nutrition has tested the combined use of  

• a microencapsulated blend of phytomolecules (Activo) for the feed and designed to maintain a good gut-health status during the whole life-cycle of the breeders, and  

• Activo Liquid, a liquid combination of phytomolecules and organic acids, which is conveniently applied on the farm via the waterline.  

1. Trial documents phytomolecules positively influencing microflora 

A trial conducted at the University of Central Queensland (Australia) showed that phytomolecules enhance beneficial bacteria such as Lactobacilli and, on the other hand, repress harmful bacteria such as Clostridium perfringens.  

For the trial, caecal microbiota of layers was used. They were grown with and without Activo Liquid in vitro, and the changes in microbiota were monitored. 

Result: The in vitro study clearly shows that Activo Liquid increases the number of lactobacilli and decreases clostridia and Enterococcus sp.  

Figure 1: Shifting intestinal balance with phytomolecules 

2.Three field trials with Activo Liquid showed an increased laying rate in breeders

 Many operations started testing phytomolecules in a farm-application-based program to reaffirm the gut health-improving activity of phytomolecules in broiler breeder performance. Especially the flexibility of assisting animals through the water for drinking during stress periods makes phytomolecules an optimal tool to support gut health.   

Two broiler breeder farms in Thailand (TH1 and TH2) and one grandparent farm in India (IN) are good examples of the effectiveness of phytomolecules. On each farm, the birds were always divided into two groups. Besides the standard management, feed, and water, one group got 200 ml Activo Liquid per 1,000 L of water. The periods when the birds received Activo in the water differed: 

TH1 & TH2: 5 days per week, during weeks 24 – 32 

IN:  5 days per week, every third week  from weeks 18 to 24 and every fourth week from 28 to 36  

The trials lasted for 9 weeks (Thailand 1 and 2) and 30 weeks (India). 

The results are shown in figure 2. The animals supplemented with Activo Liquid showed an up to 4.4 % higher laying rate and up to three more hatchable eggs per hen housed. 

Figure 2+3: Results of three trials conducted In Asia concerning laying rate and hatchable eggs 

3. Customers tell about lower breeder mortality and more DOCs due to phytomolecules 

The benefits of a tailored phytomolecule program have been demonstrated in several broiler breeder operations worldwide. For example, a combination of the in-feed (Activo) and the in-water solution (Activo Liquid) was tested in the Middle East. For the study, 75,000 23-weeks-old broiler breeders were divided into groups: 4 houses with the program, and 6 houses served as control (standard feed and water). The program, tailored to customer needs, was designed as follows: 

AC+AL group:

• Activo 100 g/ton of feed during the whole trial (weeks 23-41) + 
• Activo Liquid 250 ml/1000 L water, four days per week, weeks 23-30.  

As a result, the peak and average laying rates were higher for the flocks with the program, and laying persistency was also higher. This allowed for a significant difference of 3 total and 3.5 hatching eggs/hen housed at week 41. In both cases, an increase equivalent to 5 % compared to the control group (figure 4) could be observed. 

Figure 4: Total eggs and hatching eggs per hen housed

As fertility and hatchability were similar for both groups, the 5 % increase in hatching eggs resulted in a 5 % higher number of day-old chicks per hen housed (figure 5).

Figure 5: Number of DOSs per hen housed 

It must be mentioned that during the trial period, at 28 weeks of age, an NDV outbreak was diagnosed on the farm, which negatively impacted the overall results. However, this impact was reduced in the groups receiving the phytomolecule-based products, which also was reflected in a lower mortality rate (figure 6). 

Figure 6: Cumulative mortality rate wk 41

4. Scientific trial shows that Activo can increase post-peak productivity in breeders 

When thinking about the use of phytomolecules, most broiler breeder operations would like to consider scientific trial results in this type of animal. For EW Nutrition, it is crucial to accurately evaluate every product that reaches a market. Thus several scientific trials with broiler breeders have been performed. For one of them, Hubbard breeders (JA57 females with 80 M77 males) were divided into 2 treatments, having 5 replicate pens for each. The experiment started after the peak production period, at 34 weeks of age, and ended at week 62. To make the trial fair, the production data of 6 (pre-experimental) weeks was used to allocate the pens for each treatment, resulting in two (statistically) similar groups. 

The control group was fed the standard mash diet. For the Activo group, 100g Activo/MT was added to the diet. 

With Activo, breeders kept their high productivity after the peak, while the control group showed a steady decline from breed target values. During the experiment, Activo supplemented birds produced 3.6 more eggs than control birds (P=0.06) while consuming a similar amount of feed. As a result, a lower feed consumption per egg produced was achieved (169.9 vs. 173.6 g/egg, respectively). 

As the dietary treatment did not influence hatchability, the 3.6 extra eggs resulted in 2.9 extra day-old chicks per hen during the post-peak period, showing a positive return. 

Phytomolecules as gut health and performance promoters– antibiotics can be reduced! 

With their gut health-promoting activity, phytomolecules support breeders to better utilize nutrients. They can be invested for maintenance and the production of hatchable eggs, obtaining good quality day-old chicks.  

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Factors for successful pig production

For years we have been increasing our understanding of how to formulate diets to support a healthy intestine through the optimal use of the supplied nutrients. Functional proteins, immune-related amino acids, and fiber are now applied worldwide for improved pig nutrition.

What lies beyond formulation adjustments?

However, pig producers have also realized that these nutritional strategies alone are not always fully efficient in preventing an “irritation” of the immune system and/or in preventing diseases from happening.

Immune nutrition is gaining a strong foothold in pig production, and the body of research and evidence grows richer every year. At the same time, we see genetics continually evolving and bringing production potential to increasingly higher levels. We are also constantly increasing our understanding of the importance of farm and feed management, as well as biosecurity in this process.

Finally, the importance of a stable microflora is now uncontested. Especially around weaning, a stable microflora is necessary to prevent the proliferation of pathogens such as E.coli bacteria. Such pathogens can degrade the lysine (the main amino acid for muscle protein production) we have added to our formulations, rendering it useless.

Single molecules (or additives) are able to support the development of gut microflora, boost  its integrity, and therefore help the animals use “traditional nutrients” in a more effective way.

The impact of immune system activation on the performance of pigs

Animal performance is influenced by complex processes, from metabolism to farm biosecurity. Environmental conditions, diet formulation and feed management, and health status, among others, directly affect the amount of the genetic potential that animals can effectively express.

Among these so-called non-genetic variables, health status is one of the most decisive factors for the optimal performance from a given genotype. Due to the occurrence of (sub-) clinical diseases, the inflammatory process can be triggered and may result in a decrease in weight gain and feed efficiency.

Not so long ago, pig producers believed that a maximized immune response would always be ideal for achieving the best production levels. However, after decades spent researching what this “maximized immune response” could mean to our pigs, studies from different parts of the globe proved that an activated immune system could negatively affect animal performance. The perception is nowadays common sense within the global pig production industry.

That understanding led us to increasingly search for production systems that will yield the best conditions for the pigs. This means minimum contact with pathogens, reduced stress factors, and therefore a lower need for an activated immune system.

How immune system stimulation works

The immune system has as main objective to identify the presence of antigens – substances that are not known to the body – and protect the body from these “intruders”. The main players among these substances are bacteria and viruses. However, some proteins can also trigger an immunological reaction. Specific immune cells are responsible for the transfer of information to the other systems of the body so that it can respond adequately. This response from the immune system includes metabolic changes that can affect the demand for nutrients and, therefore, the animals’ growth.

The stimulation of the immune system has three main metabolic consequences:

• behavioral responses
• direct connection with the endocrine system and regulation of the secretions
• release of leukocytes, cytokines, and macrophages

In general, the immune system responds to antigens, releasing cytokines that activate the cellular (phagocytes) and humoral components (antibody), resulting in a decreased feed intake and an increased body temperature/heat production.

When feed formulation is concerned, possibly even more important is to understand that the activation of the immune system leads to a change in the distribution of nutrients. The basal metabolic rate and the use of carbohydrates will have completely different patterns in such an event. For instance, some glucose supplied through the feed follows its course to peripheral tissues; however, part of the glucose is used to support the activated immune system. As a consequence, the energy requirement of the animal increases.

Protein synthesis and amino acid utilization also change during this process. There is a reduction of body protein synthesis and an increased rate of degradation. The nitrogen requirement increases because of the higher synthesis of acute-phase proteins and other immunological cells.

However, increased lysine levels in the diets will not always help the piglets compensate for this shift in the protein metabolism. According to Shurson & Johnston (1998), when the immune system is activated, there is further deamination of amino acids and increased urinary excretion of nitrogen. Therefore we need to understand better which amino acids must be supplied in a challenging situation.

In pigs, the gastrointestinal tract is, to a large extent, responsible for performance. This happens because the gut is the route for absorption of nutrients, but also a reservoir of hundreds of thousands of different microorganisms – including the pathogenic ones.

Understanding  Gut Health

Gut health and its meaning have been the topic of several peer-reviewed articles in the last few decades (Adewole et al., 2016, Bischoff, 2011, Celi et al., 2017, Jayaraman and Nyachoti, 2017, Kogut and Arsenault, 2016, Moeser et al., 2017, Pluske, 2013). Despite the valuable body of knowledge accumulated on the topic, a clear and widely-accepted definition is still lacking.  Kogut and Arsenault (2016) define it in the title of their paper as “the new paradigm in food animal production”. The authors explain it as the “absence / prevention / avoidance of disease so that the animal is able to perform its physiological functions in order to withstand exogenous and endogenous stressors”.

In a recently published paper, Pluske et al. (2018) add to the above definition that gut health should be considered in a more general context. They describe it “a generalized condition of homeostasis in the GIT, with respect to its overall structure and function”. The authors add to this definition that gut health in pigs can be compromised even when no clinical symptoms of disease can be observed. Every stressful factor can undermine the immune response of pigs and, therefore, the animals’ performance.

All good information on this topic leads us to the conclusion that, without gut balance, livestock cannot perform as expected. Therefore, balance is the objective for which we formulate our pigs’ feed.

Current nutritional strategies for a stable gut microbiota

Feeding: quality of raw materials

The photos included here were taken in the field and show that taking action against this reality is a must for keeping animals healthy.

Much of this action is related to farm management. The most effective way to minimize such situations is to implement a strict control system in the feed production sites, including controlling raw material quality.

Additives can be used to improve the safety of raw materials. As already extensively discussed, everything that goes into the intestine of the animals will affect gut health and performance. Therefore,  the potential harmful load of mycotoxins should be taken into account. Besides careful handling at harvest and the proper storage of grains, mycotoxin binders can be applied to further decrease the risk of mycotoxin contamination.

The effect of nutrition on microflora: commercial weaning diet after focusing on gut health

The gut-health-focused formulation of diets must take into account the following essentials:

• decrease of gut pH
• gut wall integrity
• minimization of (pathogenic) microbial growth
• microflora modulation with consequently improved colonization resistance

Gut pH

A lower pH in the stomach slows the passage rate of the feed from the stomach to the small intestine. A longer stay of the feed in the stomach potentially increases the digestion of starch and protein. The secretion of pancreatic juices stimulated by the acidic stomach content will also improve the digestion of feed in the small intestine.

For weaned pigs, it is essential that as little as possible of the substrate will reach the large intestine and be fermented. Pathogens take advantage of undigested feed to proliferate. Lowering these “nutrients” will decrease the risk of bacterial overgrowth.

The same is true where protein sources and their levels are concerned. It is essential to reduce protein content as much as possible and preferably use synthetic (essential) amino acids. The application of such sources of amino acids has been proven long ago, and yet in some cases, it is still not fully utilized. Finally, using highly digestible protein sources should, at this point, be a matter of mere routine.

All these strategies have the same goal: the reduction of undigested substances in the gut. Additionally, the reduction of the protein levels can also decrease the costs of the diets.

Further diet adjustments

Further diet adjustments, such as increasing the sulfur amino acids (SAA) tryptophan and threonine to lysine ratio, must also be considered (Goodband et al., 2014; Sterndale et al., 2017). Although the concept of better balancing tryptophan and threonine are quite clear among nutritionists, SAA are sometimes overestimated. Sulfur amino acids are the major amino acids in proteins related to body maintenance, but not so high in muscle proteins. Therefore, the requirement of SAA must also be approached differently. Unlike lysine, the requirements of SAA tend to be higher in immunologically stimulated animals (Table 1).

Table 1. Effect of the immune system activation on the demand for lysine and sulfur amino acids in pigs (Stahly et al., 1998) 

*ISA – immune system activation

Vitamins and minerals are classic nutrients to be considered when formulating gut health-related diets. Maybe not so extensive as the amino acids and protein levels, these nutrients have, however, been found to carry benefits in challenging situations. In the past several years, a lot was published on the requirements of pigs facing an activation of the immune system. Stahly et al. (1996) concluded that when the immune system is activated, the phosphorous requirements change.

Table 2. Effect of the immune system activation on the performance and phosphorous requirements of pigs (Stahly et al., 1998)

*ISA – immune system activation

Another example is vitamin A. It is involved in the function of macrophages and neutrophils. Vitamin A deficiency decreases the migratory and phagocytic abilities of the immune cells. A lower antibody production is observed in vitamin A deficiency as well. Furthermore, vitamin A is an important factor in mucosal immunity, because this vitamin plays a role in lymphocyte homing in the mucosa (Duriancik et al., 2010).

Phytomolecules: key additives to support gut health

Phytomolecules are currently considered one of the top alternatives to in-feed antibiotics for pigs worldwide. Programs sponsored by the European Union are once more evaluating the effectiveness of these compounds as part of a strategy to produce sustainable pigs with low or no antibiotic use. The EIP-Agri (European Innovation Partnership “Agricultural Productivity and Sustainability”) released a document with suggestions to lower the use of antibiotics in feed by acting in three areas:

• improving pig health and welfare
• changing attitudes and human habits
• finding specific alternatives to antibiotics

Under the last topic, the commission recommends plant-based feed additives to be further examined.

Antibiotics have been used for many years for supporting performance in animal production, especially in critical moments. The mode of action consists of the reduction of pathogen proliferation and inflammation processes in the digestive tract. These (soon-to-be-) banned compounds therefore reduce the activation of the immune system, helping keep pigs healthy through a healthy gastrointestinal tract. As potential alternatives to antibiotic usage, phytomolecules should be able to do the same.

The mode of action of phytomolecules

Antimicrobial

Most phytomolecules used nowadays aim to control the number and type of bacteria in the gut of animals.  According to Burt (2004), the antimicrobial activity of phytomolecules is not the result of one specific mode of action, but a combination of effects on different targets of the cell. This includes disruption of the membrane by terpenoids and phenolics, metal chelation by phenols and flavonoids, and protective effects against viral infections for certain alkaloids and coumarins (Cowan, 1999).

Digestion support

The antimicrobial efficacy is one of the most important activities of secondary plant compounds, but it also impacts digestion. Windisch et al. (2008) states that growth-promoting agents decrease immune defense stress during critical situations. They increase the intestinal availability of essential nutrients for absorption, thus promoting the growth of the animal.

Indeed, phytomolecules are a good tool for stabilizing the gut microbiota. But more can be expected when adding this class of additives into your formulation and/or farm operations. Mavromichalis, in his book “Piglet Nutrition Notes – Volume 2”, brings attention to the advantages of using phytomolecules such as capsaicin, which is often related to increased feed intake. Recent research has demonstrated that capsaicin increases the secretion of digestive enzymes that may result in enhanced nutrient digestibility. According to Mavromichalis, this can lead to a better feed conversion rate as more nutrients are available to the animal. Indirectly, this also helps control the general bacterial load in the gut.

Antioxidant support

This results from the polyphenols’ capacity to act as metal-chelators, free radical scavengers, hydrogen donators, and inhibitors of the enzymatic systems responsible for initiating oxidation reaction. Furthermore, they can act as a substrate for free radicals such as superoxide or hydroxyl, or intervene in propagation reactions.

This variety of benefits explains at least partially the high level of interest in this group of additives for pigs under challenging conditions. For the production of effective blends, it is crucial to understand the different modes of action of the phytomolecules and the probable existing synergies. Furthermore, the production technology  must be considered. For instance, microencapsulation techniques that prevent losses during feed processing are an important consideration.

Not to be discarded: Biosecurity

The recent outbreak of African Swine Fever focused our attention on something that is sometimes neglected on the farm: biosecurity rules. According to the report “Good Practices For Biosecurity In The Pig Sector” (2010), the three main elements of biosecurity are:

• segregation
• cleaning
• disinfection

In general terms, the following steps must be adopted with the clear goal of reducing the challenges that the pigs are facing.

• Farms must be located far from other farms (regardless of the species) and ideally must be protected with natural (forest/woods) or physical barriers.
• Only one entrance must be used to go into the farm (for both vehicles and people) and a disinfection procedure must be in place, either by an automatized system or by manual application of disinfectants. Equipment disinfection systems must also be in place.
• Workers and any other person that enters the facility should adhere to strict biosecurity measures 24/7. The farms must have a visitors’ book including relevant data on previous visits to farms (regardless of the species).
• Trucks and visitors should not have been in contact with other pigs recently (at least 48 hours previous to the visit).
• Only farm workers are allowed to go into the barns unless special approval is given (followed by strict biosecurity measurements prior to the visit).
• The use of clothing and footwear that are worn only in the pig unit (and certainly not during visits to other pig farms) is recommended.
• No materials (e.g. tools) can be moved from one barn to another barn. People that enter a barn should change footwear and wash their hands with soap for at least 10 seconds.

These simple actions can make a big difference to the performance of the pigs, and as a consequence to the profitability of a swine farm.

Take-home messages

Different formulations and reassessed nutritional level recommendations have been on the radar for a couple of years. It is high time to consider using efficient additives to support the pigs’ gut health. Phytomolecules appear as one of the most prominent tools to reduce pathogenic stress in pig production. Either via feed or water, phytomolecules are proven to reduce bacterial contamination and therefore reduce the need for antibiotic interventions. Furthermore, a more careful look at our daily activities in the farm is crucial. Paying attention to biosecurity and to feed safety should be standard tools to improve performance and the success of pig production operations.

References are available upon request.

*The article was initially published in the PROCEEDINGS OF THE PFQC 2019

by  Merideth Parke, Regional Technical Manager, EW Nutrition

To contain and reverse antimicrobial resistance, consumers and government regulators expect changes in pork production with the clear goal to reduce antibiotic use. For healthy, profitable pig production with simultaneous antibiotic reduction, a holistic strategy is required: refocusing human attitudes and habits, optimal pig health and welfare, and applying potential antibiotic alternatives.

Pig producers need to manage pathogenic pressure while reducing antibiotics

Intensive pig production has stress points associated with essential husbandry procedures such as weaning, health interventions, and dietary modifications. Stress is widely accepted to have a negative impact on immune system effectiveness, enhancing opportunities for pathogenic bacteria to invade at a local or systemic level. The gastrointestinal and respiratory systems are highly susceptible to developing disease as a result of these combined factors. Interventions such as antibiotics are commonly implemented to reduce the impact of pathogens and manage pig health. Processes that minimize the number of pathogens in the environment are the foundation for a successful antibiotic reduction plan. The challenge is to smartly combine strategies to keep the gastrointestinal and respiratory tract intact and robust.

Phytomolecules, the specific active defense compounds found in plants, have been identified as capable of enhancing pig health through antimicrobial (Cimanga et al., 2002, Franz et al., 2010), antioxidative (Katalinic et al., 2006, Damjanovic-Vratnica et al., 2007, Lee et al., 2011), digestion-stimulating and immune-supportive functions. As many thousands of phytomolecules exist,  laboratory research has focused on identifying those with the capability of microbial management, facilitating the end goal of reducing the reliance on antibiotics for pig health and welfare and the production of safe pork (Zhai et al., 2018).

Which roles can phytomolecules play in reducing antibiotics?

The gastrointestinal tract benefits from applying phytomolecules such as capsaicin, carvacrol, and cinnamaldehyde, as they:

• support a balanced and stable biome,
• prevent dysbiosis, maintain tight junction integrity (Liu et al., 2018),
• increase secretion of digestive enzymes, and
• enhance gut contractility (Zhai et al., 2018).

Pigs most susceptible and in need of phytomolecule gastrointestinal supportive actions are piglets at weaning and pigs of all ages undergoing stress, pathogen challenges, and/or dietary changes.

Porcine respiratory disease is a complex multifactorial disorder. It frequently requires antibiotics to manage infection pressure and clinical disease to maintain pig health, welfare, and production performance. Causal pathogens may be transmitted by direct contact between pigs in saliva (Murase et al., 2018) or bioaerosols (LeBel et al., 2019), via the nasal or oral cavities (inhalation directly into the airways and lungs), or via an unhealthy gut. Phytomolecules such as carvacrol and cinnamaldehyde have antimicrobial properties. Hence, they may help contain respiratory pathogens in their natural habitat (the upper respiratory tract) or during transit through the oronasal cavity and gastrointestinal tract (Swildens et al., 2004, Lee et al., 2001).

In addition to supporting the gastrointestinal and respiratory systems, phytomolecules such as menthol and 1,8-cineole have been shown to enhance the physical and adaptive immune systems in multiple species (Brown et al., 2017, Barbour et al., 2013). When applied via drinking water, adherence to the oronasal mucosa facilitates the inhalation of the active phytomolecule compounds into the respiratory tract. There, they act as mucolytics, muscle relaxants, and enhancers of the mucociliary clearance mechanism (Başer and Buchbauer, 2020). Phytomolecules have also been documented to positively influence the adaptive immune system, promoting both humoral and cell-mediated immune responses (Awaad et al., 2010, Gopi et al., 2014, Serafino et al., 2008).

How phytomolecules feature in the holistic approach to antibiotic reduction

Antibiotic reduction programs positively enact social responsibility by reducing the risk to farmworkers of exposure to antimicrobial-resistant bacteria. They also help maintain or increase efficiency in safe pork production – pork with minimal risk of antibiotic residues.

Implementation of a successful health program with reduced antibiotic use will require:

• application of strict internal and external biosecurity processes;
• evaluation and monitoring of AMR bacteria;
• partnerships with specialist nutritionists to target a lifetime healthy gut biome; and
• phytomolecule-assisted health management (Figure 1).

A combination of in vitro and in vivo studies provides evidence that specific phytomolecules can support both enteric and respiratory systems through biome stabilisation and pathogen management (Bajabai et al., 2020). Antimicrobial activity of thymol, carvacrol, and cinnamaldehyde has been reported against respiratory pathogens including S. suis, A. pleuropneumoniae, and H. parasuis (LeBel et al., 2019); multi-drug resistant and ESBL bacteria (Bozin et al., 2006); enteric pathogens including E. coli, Salmonella enteritidis, Salmonella cholerasuis, and Salmonella typhimurium (Penalver et al., 2005); Clostridium spp., E. coli spp., Brachyspira hyodysenteriae (Vande Maelle et al., 2015); and Lawsonia intracellularis (Draskovic et al., 2018). These results have shown phytomolecules to be effective antimicrobial alternatives for incorporation into holistic pig health programs.

Additionally, the inclusion of phytomolecules into pig production systems also enhances production performance by reducing the negative impact of stress on the pig and increasing the positive effects on gut health and nutrient utilization (Franz et al., 2010). Phytomolecules that directly impact digestive actions include capsaicin, which optimizes the production of digestive enzymes and increases serotonin for gut contraction maintenance and improved digesta mixing (Zhai et al., 2018). Cineol’s antioxidative activities provide support during times of stress (Cimanga et al., 2002).

Phytomolecules are key to reducing antibiotics in pig production

The pig industry searches for alternatives to therapeutic, prophylactic, and growth-promoting antibiotic applications to keep available antibiotics effective for longer – and to address the social responsibility of mitigating AMR. This search for ways to produce safe pork has made it clear that only a combination of management and antibiotic alternatives can achieve these aligned goals.

Biosecurity, hygiene, stress reduction, and husbandry and nutritional advances form the foundation for the strategic application of specific phytomolecules (Zeng et al. 2016). Supporting pig production and health, this complete holistic solution (EIP-AGRI) moves the pig industry into a future where antibiotic reduction or removal, with equivalent or increased production of safe pork, becomes a reality.

References

Awaard M, Abdel-Alim G, Sayed K, Kawkab, Ahmed1 A, Nada A , Metwalli A, Alkhalaf A. “Immunostimulant effects of essential oils of peppermint and eucalyptus in chickens”. Pakistan Veterinary Journal (2010). 2:61-66. http://www.pvj.com.pk/

Bajagai YS, Alsemgeest J, Moore RJ, Van TTH, Stanley D. “Phytogenic products, used as alternatives to antibiotic growth promoters, modify the intestinal microbiota derived from a range of production systems: an in vitro model”. Applied Microbiology and Biotechnology (2020). 104:10631-10640. https://doi.org/10.1007/s00253-020-10998-x

Barbour EK, Shaib H, Azhar E, Kumosani T, Iyer A, Harakey S, Damanhouri G, Chaudary A, Bragg RR. “Modulation by essential oil of vaccine response and production improvement in chicken challenged with velogenic Newcastle disease virus”. Journal of Applied Microbiology (2013). 115, 1278-1286. https://doi:10.1111/jam.12334

Biljana Damjanovic-Vratnica, Tatjana Dakov, Danijela Sukovic, Jovanka Damjanovic. “Antimicrobial effect of essential oil isolated from Eucalyptus globulus Labill” (2011). Czech Journal of Food Science 27(3):277-284. https://www.agriculturejournals.cz/publicFiles/39925.pdf

Bozin B, Mimica-Dukic N, Smin N, Anackov G. “Characterization of the volatile composition of essential oils of some Lamiaceae spices and the antimicrobial and antioxidant activities of the entire oils” Journal of Agriculture and Food Chemicals (2006). 54:1822-1828 https://pubs.acs.org/doi/10.1021/jf051922u

Brown SK, Garver WS, Orlando RA. “1,8-cineole: An Underappreciated Anti-inflammatory Therpeutic” Journal of Biomolecular Research &Therapeutics (2017). 6:1 1-6  https://doi: 10.4172/2167-7956.1000154

Cimanga K., Kambu K., Tona L., Apers S., De Bruyne T., Hermans N., Totte J., Pieters L., Vlietinck A.J. “Correlation between chemical composition and antibacterial activity of essential oils of some aromatic medicinal plants growing in the Democratic Republic of Congo”. Journal of Ethnopharmacology (2002) 79: 213–220. https://doi.org/10.1016/s0378-8741(01)00384-1

Draskovic V, Bosnjak-Neumuller J, Vasiljevic M, Petrujkic B, Aleksic N, Kukolj V, Stanimirovic Z. “Influence of phytogenic feed additive on Lawsonia intracellularis infection in pigs” Preventative Veterinary Medicine (2018). 151: 46-51 https://doi.org/10.1016/j.prevetmed.2018.01.002

European Innovation Partnership Agricultural Productivity and Sustainability (EIP-AGRI). https://ec.europa.eu/eip/agriculture/en/european-innovation-partnership-agricultural

Franz C., Baser KHC, Windisch W. “Essential oils and aromatic plants in animal feeding-a European perspective. A review Flavour”. Flavour and Fragrance Journal (2010) 25:327-40. https://doi.org/10.1002/ffj.1967

Gopi M, Karthik K, Manjunathachar H, Tamilmahan P, Kesavan M, Dashprakash M, Balaraju B, Purushothaman M. “Essential oils as a feed additive in poultry nutrition”. Advances in  Animal and Veterinary Sciences (2014) 1:17.  https://doi.10.14737/journal.aavs/2014.2.1.1.7

Başer, Kemal Hüsnü Can, and Gerhard Buchbauer. Handbook of Essential Oils Science, Technology, and Applications. Boca Raton: CRC Press, 2020.

Hengziao Zhai, Hong Liu, Shikui Wang, Jinlong Wu, Anna-Maria Kluenter. “Potential of essential oils for poultry and pigs.” Animal Nutrition 4 (2018): 179-186.  https://doi.org/10.1016/j.aninu.2018.01.005

Katalinic V., Milos M., Kulisic T., Jukic M. “Screening of 70 medicinal plant extracts for antioxidant capacity and total phenols”. Food Chemistry (2006) 94(4):550-557.  https://doi.org/10.1016/j.foodchem.2004.12.004

LeBel G., Vaillancourt K., Bercier P., Grenier D. “Antibacterial activity against porcine respiratory bacterial pathogens and in vitro biocompatibility of essential oils”. Archives of Microbiology (2019) 201:833-840; https://doi.org/10.1007/s00203-019-01655-7

Lee KG, Shibamoto T. “Antioxidant activities of volatile components isolated from Eucalyptus species”. Journal of the Science of Food and Agriculture (2001). 81:1573-1597. https://doi.org/10.1002/jsfa.980

Liu SD, Song MH, Yun W, Lee JH, Lee CH, Kwak WG Han NS, Kim HB, Cho JH. “Effects of oral administration of different dosages of carvacrol essential oils on intestinal barrier function in broilers” Journal of Animal Physiology and Animal Production (2018) https://doi.org/10.1111/jpn.12944

Murase K, Watanabe T, Arai S, Kim H, Tohya M, Ishida-Kuroki K, Vo T, Nguyen T, Nakagawa I, Osawa R, Nguyen N, Sekizaki T. “Characterization of pig saliva as the major natural habitat of Streptococcus suis by analyzing oral, fecal, vaginal, and environmental microbiota”. PLoS ONE (2019). 14(4). https://doi.org/10.1371/journal.pone.0215983

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Serafino A, Vallebona PS, Adnreola F, Zonfrillo M, Mercuri L, Federici M, Rasi G, Garaci E, Pierimarchi P. “Stimulatory effect of Eucalyptus essential oil on innate cell-mediated immune response” BioMed Central (2008). 9:17 https//:doi:10.1186/1471-2172-9-17

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Vande Maele L, Heyndrickx M, Maes D, De Pauw N, Mahu M, Verlinden M, Haesbrouck F, Martel A, Pasmans F, Boyen F. “In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components”. Journal of Veterinary Medical Science (2016). 78(2):325-328.  https://doi.org/10/1292/jvms.15-0341

Zeng Z, Zhang S, Wang H, Piao X. “Essential oil and aromatic plants as feed additives in non-ruminant nutrition: a review”. Journal of Animal Science and Biotechnology (2015) 6:7. https://doi.org?10/1186/s40104-015-004-5

Strong demand by consumers; restaurant chains and wholesalers for antibiotic-free (ABF) meat; the threat of antimicrobial resistance; and stringent regulations on the use of antibiotics – there are many good reasons for poultry producers to strive for antibiotic-free production systems. Crucially, to successfully produce poultry meat without antibiotics requires a paradigm shift that starts right at the parent stock level, with the antibiotic-free production of hatching eggs.

Broiler breeders’ gut health is linked to progeny’s performance

Broiler breeders’ performance is measured in terms of how many saleable day old chicks (DOCs) per hen they produce. However, within a sustainable ABF production system (also known as No Antibiotics Ever or NAE), this parameter is not seen in isolation. Breeder hens’ nutritional and health status not only affect the number of DOCs they can produce, but also the transfer of nutrients, antibodies, microbiota and even contaminants, e.g. mycotoxins, to the egg – and therefore, their progeny’s long-term health and performance.

This starts with egg formation, which requires several metabolic processes in the hen to function perfectly. If the hen’s intestinal integrity is compromised, for example due to mycotoxins, she will absorb fewer nutrients, which in turn affects egg formation. Mycotoxicosis has particularly insidious effects for egg formation as it can damage the liver whose biosynthetic activities strongly impact on the egg’s internal (yolk) and external (eggshell) quality.

Chick embryos depend on the maternal antibodies and nutrients deposited in the yolk, including vitamin D3, carotenoids, and fatty acids, to develop normally. Eggshell quality, among other things, affects the embryo’s access to oxygen, which is especially important when it develops body tissues.

Hens’ ability to form healthy eggs depends on their diet and health. Research indicates that, via the impact on egg formation, broiler breeders’ feeding program quantifiably influences their progeny’s immune system and intestinal health. There is indeed a direct relationship between parent and offspring’s gut health because the chick’s microbiome is in part also inherited from the hen. The impact on DOC quality is thus one of many dimensions to consider when calibrating one’s broiler breeders feeding approach.

The challenge of feeding an ABF broiler breeder

Just as their offspring, breeder hens are genetically predisposed for rapid growth and muscle development. From rearing right through to the laying period, poultry nutritionists need to carefully balance their diets and moderate weight gain in order for hens to reach their reproductive potential.

Different stages of a breeder’s life cycle come with different objectives – for example, good flock uniformity in the rearing period versus egg size and hatchability in the laying phase – and thus different requirements in terms of calories, amino acids, vitamins, and minerals. What remains constant is that the actual nutrient intake depends on intestinal health, determining both the breeders’ performance and, via the impact on egg characteristics, its progeny’s performance.

The feeding regimes adopted to avoid hens becoming overweight can have a negative effect on their gut flora. Without antibiotics as a tool to maintain or recover optimal gut function, even mild intestinal disorders can quickly become chronical impairments that negatively impact breeders’ productivity. In ABF production systems, intestinal health therefore needs to be a central focus for the feeding strategy.

Can phytomolecules improve broiler breeders’ performance?

Among the plethora of feed additives, phytomolecules, or secondary plant compounds, stand out as a class of active ingredients that may help to improve gut health and thereby reduce the use of antibiotics.  Synthesized by plants as a defense mechanism against pathogens, phytomolecules combine digestive, antimicrobial and antioxidant properties.

Some studies have shown that phytomolecules-based products can increase broilers’ body weight gain and improve laying hens’ laying rate, egg mass and egg weight. Both broilers and laying hens responded to the inclusion of phytomolecules in their diet with inclusion rate-dependent improvements in feed conversion. To evaluate if phytomolecules could similarly improve broiler breeders’ performance, two trials were conducted.

Study I: Effect of phytomolecules on laying performance during peak production

The first study was set up on a farm in Thailand. In total, 40000 Cobb broiler breeders (85% female, 15% male) were divided into two groups with 8500 hens (one house) in the control and 25500 (three houses) in the trial group. Both groups were fed standard feed. The trial group additionally received a phytomolecules-based liquid complementary feed (Activo® Liquid, EW Nutrition GmbH) via the waterline from week 24 to week 32 at a rate of 200ml/1000L during 5 days per week.

Activo® Liquid was found to have a positive influence on laying performance (Figure 1). The average laying rate increased by 7.2% during the trial period, resulting in almost 3 additional hatching eggs per hen housed. A further indication of the beneficial influence that this particular combination of phytomolecules had on gut health was a 0.2% lower mortality.

Figure 1: Laying rate (%) of breeder hens during first 9 weeks of production

Study II: Effect of phytomolecules on laying performance after peak production

For a second study, conducted in the Czech Republic, 800 female and 80 male Hubbard breeders (JA57 and M77, respectively) were divided into 2 groups with 5 replicate pens and 80 female and 8 male breeders per pen. The experiment started after the peak-production period, at 34 weeks of age and ended at 62 weeks of age. All animals received a standard mash diet. For one group a phytogenic premix (Activo^®, EW Nutrition GmbH) was added to the diet at a rate of 100g/MT.

The results indicate that Activo^® helped maintain the breeder hens’ egg laying performance close to the breed’s genetic potential (Figure 2). In the course of the experiment, Activo® supplemented birds produced 3.6 more eggs than control birds, while consuming a similar amount of feed. As a result, feed consumption per egg produced was lower for birds receiving phytomolecules than for the control birds (169.9 versus 173.6g/d, respectively).

As hatchability was not influenced by the dietary treatment in this study (P>0.5), the 3.6 extra eggs resulted in 2.9 extra day old chicks per hen produced, during the post-peak period alone.
The microencapsulated, selected phytomolecules contained in Activo^® are likely to have improved gut health and feed digestibility, and thereby enhanced the animals’ feed efficiency.

Figure 2: Laying rate (%) of breeder hens week 35 till 62

Chicken or egg? Antibiotic-free poultry production looks at the bigger picture

To successfully produce antibiotic-free poultry meat requires a systematic re-think of each component of the production process. Broiler breeders’ lay the foundation for their progeny’s health and performance via the egg. Breeder hens need to be in optimal health to consistently deliver optimal eggs. Without recourse to antibiotics for maintaining or recovering intestinal functionality, an effective ABF production needs to make gut health central to its feeding approach.

The trials reviewed demonstrate that selected phytomolecules quantifiably boost breeders’ laying performance, increasing the number of hatching eggs and DOCs, while reducing mortality and feed consumption per egg produced. As part of an intelligent antibiotic reduction strategy, the right phytogenic products can be potent tools to help poultry producers achieve their NAE objectives.

by S. Regragui Mazili, T. van Gerwe and M. Caballero

References

Calini, F., and F. Sirri. “Breeder Nutrition and Offspring Performance.” Revista Brasileira De Ciência Avícola 9, no. 2 (2007): 77-83. doi:10.1590/s1516-635×2007000200001.

Ding, Jinmei, Ronghua Dai, Lingyu Yang, Chuan He, Ke Xu, Shuyun Liu, Wenjing Zhao, et al. “Inheritance and Establishment of Gut Microbiota in Chickens.” Frontiers in Microbiology 8 (October 10, 2017): 1967.

Kuttappan, Vivek A., Eduardo A. Vicuña, Juan D. Latorre, Amanda D. Wolfenden, Guillermo I. Téllez, Billy M. Hargis, and Lisa R. Bielke. “Evaluation of Gastrointestinal Leakage in Multiple Enteric Inflammation Models in Chickens.” Frontiers in Veterinary Science 2 (December 14, 2015): 66.

Moraes, Vera M. B., Edgar O. Oviedo-Rondón, Nadja S. M. Leandro, Michael J. Wineland, Ramon D. Malheiros, and Pamela Eusebio-Balcazar. “Broiler Breeder Trace Mineral Nutrition and Feeding Practices on Embryo Progeny Development.” Avian Biology Research 4, no. 3 (2011): 122–32.

Oviedo-Rondon, Edgar O., Nadja S. M. Leandro, Rizwana Ali, Matthew Koci, Vera M. B. Moraes, and John Brake. “Broiler Breeder Feeding Programs and Trace Minerals on Maternal Antibody Transfer and Broiler Humoral Immune response1.” The Journal of Applied Poultry Research 22, no. 3 (October 1, 2013): 499–510.

As the producers of hatching eggs and day-old chicks, breeding hens are the backbone of the poultry industry. Hence it is common practice to pay particular attention to this valuable asset’s feed, selecting raw materials of high nutritional quality and safety. However, in any feed formulated for animals in production and reproduction, studies show that it is almost inevitable to find a certain level of mycotoxin contamination.

Mycotoxins exert toxic effects mainly on the gastrointestinal tract, liver, and kidneys and can accumulate in some tissues but also in the eggs. Mycotoxin contamination in breeder hens rations does not always lead to visible symptoms, such as when trichothecenes cause oral lesions. However, it may influence productivity, egg quality, hatchery performance, as well as chick quality and immunity. Mycotoxin risk management is thus an essential part of managing breeder hens. Mycotoxins can negatively affect eggshell quality and, as a consequence, embryonic mortality.

By Marisabel Caballero, Global Technical Manager Poultry at EW Nutrition.

Type of mycotoxin and exposure time determine effect on egg production

Mycotoxicosis in hens can cause reduced egg production, most likely because it causes a decrease in protein synthesis. A lower synthesis of albumin results from a degeneration of the liver tissue due to aflatoxin, ochratoxin, T2 and DON exposure. The liver then may look pale, friable and occasionally shows superficial hemorrhages.

The contamination levels at which these effects can be observed are as low as 100ppb in feed, for example, during a 21-day exposure to ochratoxin (Figure 1). With increasing levels of the toxin, production further decreases. A similar effect is observed when breeder hens are exposed to aflatoxins.

Figure 1 – Effect of mycotoxins on egg production, compared to non-contaminated control (=100 %)

Egg production, however, is not the only parameter that is affected when breeding hens are exposed to mycotoxins. Earlier on in the reproductive cycle, they already impact on embryonic mortality and hatchability. These effects are potentially more severe and may even occur without any noticeable change in the number of eggs produced.

Mycotoxins’ insidious consequences for eggshell quality and embryonic mortality

The eggshell is important to protect the progeny: thin and fragile shells can increase embryonic mortality, lower embryonic weight gain and decrease hatchability. Eggshell quality is a function of the hen’s calcium and vitamin D3 metabolism. The bioavailability of calcium and of vitamin D3 depends on intestinal integrity and on the production of enzymes and transporters that aid in feed metabolism. These processes can be adversely affected by aflatoxins, DON, T2, and Fumonisins.

The gastrointestinal tract is not the only site of mycotoxin action, however. Mycotoxins such as aflatoxins and ochratoxins have nephrotoxic effects, affecting calcium metabolism and increasing its excretion via the urine, while lowering its levels in blood serum.

Moreover, mycotoxins damage the liver, which plays a central role in egg production, being responsible for vitamin D3 metabolism and the synthesis of the lipids that make up the yolk. Moreover, the synthesis of transporters for lipids, calcium, and carotenoids   ̶  important components of the egg  ̶  also takes place in the liver. When liver function is impaired, the internal and external quality of the egg declines, which, in the end, affects the production of day-old chicks.

Figure 2 – Effects of mycotoxins on eggshell quality and embryonic mortality

Figure 2 summarises the possible ways in which mycotoxins can negatively affect eggshell quality and, as a consequence, increase embryonic mortality. If a hen’s intestinal integrity is compromised, the utilization of nutrients decreases. Liver and kidney damage leads to a diminished availability of calcium and other nutrients necessary for egg formation. The birds’ calcium (and phosphorus) levels in the plasma are then lower and may lead to a greater mobilization of calcium from the bones. However, this response cannot be maintained and the eggs get a thinner shell.

The thickness of the eggshell influences the egg’s moisture loss and exchange with the environment during the incubation period. An eggshell of optimal quality does not allow the loss of nutrients and prevents bacterial contamination. Thinner eggshells are less able to fulfill these functions, leading to higher embryo mortality.

Figure 3 – Effects of mycotoxins on embryonic mortality

Figure 3 shows the effect of different mycotoxins on embryonic mortality. Incremental levels of ochratoxin or aflatoxin heighten embryonic mortality in a range from 1.5 to 7.5 times the embryonic mortality of the control group. In some cases, embryos are affected even when the hens received feed contaminated with mycotoxin levels that are within the guidelines suggested by the EFSA.

For example, an exposure to 4900ppb of DON for ten weeks increases the number of embryos with abnormalities. The causes are not entirely clear, as only traces of DON can be found in the egg. However, we do know that this mycotoxin can affect the protein synthesis at the level of the hen’s liver and therefore compromise the deposition of nutrients into the egg.

Mycotoxins’ effects on the progeny may cause long-term damage

Ochratoxin and aflatoxin can be transferred into the egg, where they exert toxicity on the embryos. This does not necessarily result in mortality. However, the chicks can suffer from a compromised immune function due to two reasons: lower transmission of antibodies from the hen and lower viability of the chickens’ immune cells, accompanied by a lower relative weight of the bursa of Fabricio and the thymus.

When both aflatoxin and ochratoxin are present in the feed, the effect on these parameters is synergistic. As a consequence of mycotoxin contamination, the animals’ immune response is impaired, which makes them more susceptible to infection. The final result could be increased early chick mortality due to a higher incidence of bacterial and viral infections.

The transmission of other mycotoxins into the egg is minimal. While this means that a direct effect on the progeny is unlikely to occur, mycotoxin contamination still has a snowball effect: we have to consider the indirect effect of a lower deposition of nutrients on chick quality.

Prevention is key: mycotoxin risk management for breeder hens

The best approach to manage mycotoxin risk is to implement an integrated strategy that includes good crop and grain storing practices, regular raw material sampling and mycotoxin evaluation and analysis. Management tools (such as MasterRisk) can help to evaluate mycotoxin interactions and to choose the best strategy for dealing with specific mycotoxin challenges.

The results of mycotoxin analyses can be used to take decisions regarding the inclusion levels of raw materials and in choosing feed additives that counteract mycotoxins. Products based on plant extracts, yeast cell walls, and clay minerals can help to stabilize a digestive system challenged by mycotoxins. They support the barrier function in the intestine, preventing the passage of mycotoxins into the bloodstream.

Phytomolecules are another piece of the puzzle: thanks to their antimicrobial, anti-inflammatory and antioxidant properties, they support liver function. This is particularly important for long-living animals prone to accumulating mycotoxins in their body tissues.

For a long time the “deleterious effects” of mycotoxins on breeder hens and “their repercussions on progeny health status and performance have not received from a scientific point of view as much attention”(Calini and Sirri, 2007) as they ought to have. However, now that the dangers of mycotoxins for breeder hens’ welfare, health and performance are better understood, it is clear that mycotoxin risk evaluation and management is central to successful poultry production.

*This article first appeared in All About Feed on 31 October 2018

Reference:

Photo: Hans Prinsen.

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 01, 2000): 856-63 doi:10.1093/ps/79.6.856. 

Brake, J., P. Hamilton, and R. Kittrell. “Effects of the Trichothecene Mycotoxin Diacetoxyscirpenol on Egg Production of Broiler Breeders.” Poultry Science 81, no. 12 (December 01, 2002): 1807-810 doi:10.1093/ps/81.12.1807.

Bryden, Wayne L. “Mycotoxin Contamination of the Feed Supply Chain: Implications for Animal Productivity and Feed Security.” Animal Feed Science and Technology 173, no. 1-2 (2012): 134-58 doi:10.1016/j.anifeedsci.2011.12.014.

Calini, F., and F. Sirri. “Breeder Nutrition and Offspring Performance.” Revista Brasileira De Ciência Avícola 9, no. 2 (2007): 77-83 doi:10.1590/s1516-635×2007000200001. 

Hester, Patricia Y. “Improving Egg Production and Hen Health with Calcium.” In Egg Innovations and Strategies for Improvements, edited by Patricia Y. Hester, 319-29. London: Academic Press, 2017 doi:10.1016/b978-0-12-800879-9.00030-5.

Ul-Hassan, Zahoor, Muhammad Zargham Khan, Ahrar Khan, Ijaz Javed, and Muhammad Kashif Saleemi. ” Immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)- and aflatoxin B1 (AFB1)-contaminated feeds.” Journal of Immunotoxicology 9, no. 4 (April 24, 2012): 381-91. doi:10.3109/1547691X.2012.675365.

The large majority of poultry specialists in Europe consider phytomolecules as one of the key elements in diets for broilers, broiler breeders, and layers when birds are raised without antibiotics. A quick glance at the market will reveal more commercial products than can possibly be imagined. There are three basic elements you should bear in mind when making your choice:

1. Most phytomolecules are volatile. As such, unprotected products will soon evaporate if left exposed to the open air – as it happens, for instance, with feed prepared in commercial farms. Microencapsulation is therefore essential.
2. There are countless phytomolecules. Consequently, finding the right mix for the task required is essential, as not all mixtures will get you the desired result. When designing a phytomolecule mix, the manufacturer must have the necessary knowledge and experience to achieve the desired result.
3. Phytomolecules are powerful. This is to say that you cannot just keep adding higher quantities to achieve a better result. Finding the exact inclusion rates for the right purpose is a difficult balancing exercise.

In fact, the right protection, the right mix and the right inclusion rates must be combined to ensure that the animals do not refuse the feed (worst case scenario) or just fail to benefit from the inclusion of phytomolecules.

Among the feed additives, phytomolecules (or secondary plant compounds) stand out as a class of active ingredients that may help to improve gut health and thereby reduce the use of antibiotics.  Synthesized by plants as a defense mechanism against pathogens, phytomolecules promote the digestion of feed ingredients (Zhai et al. 2018), prevent loss of gut integrity during enteric challenges (Liu et al. 2018), and have antimicrobial properties that hinder the growth of potential pathogens (Chowdhury, 2018). Phytomolecules can prevent the overgrowth of opportunistic pathogens, thereby reducing the frequency of occurrence of diseases such as necrotic enteritis and dysbacteriosis and thus improve performance data such as daily weight gain and feed efficiency.

Beyond the phytomolecules’ proven effects, what works best in supporting the health and welfare of your animals is, in fact, a holistic program (such as those offered by EW Nutrition) that consists of an effective combination of innovative products and consultancy services in the fields of gut health, nutrition, AMR monitoring, and biosecurity management.

*This article is available in Dutch.

Antibiotic growth promoters (AGPs) have routinely been used in intensive poultry production for improving birds’ performance. However, in recent years, reducing the use of antibiotics in animal production has become a top priority, due to concerns about the development of antibiotic-resistant bacteria and mounting consumer pressure. Multiple countries have introduced bans or severe restrictions on the non-therapeutic use of antibiotics, including in the US, where the Food and Drug Administration has implemented measures to curb the use of antibiotics since 2017.

However, the removal of AGPs poses challenges for poultry performance, including reduced feed efficiency, decreased daily weight gain, as well as higher mortality. Moreover, the withdrawal of AGPs in feed is widely recognized as one of the predisposing factors for necrotic enteritis (NE). NE is one of the most common and economically important poultry diseases, with an estimated global impact of US$ 5 to 6 billion per year. As a result of withdrawing AGPs, the usage of therapeutic antibiotics to treat NE has increased. To break out of this vicious cycle and to secure the efficiency of poultry production, alternatives are needed that combat NE where it starts: in the gut.

Necrotic enteritis: a complex disease

NE is caused by pathogenic strains of Clostridium perfringens (CP): ubiquitous, gram-positive, spore-forming anaerobic bacteria. The spores of CP can be found in poultry litter, feces, soil, dust, and contaminated feed. Low levels of different CP strains are naturally present in the intestines of healthy birds, kept in check by a balanced microbiome. However, when gut health is compromised, pathogenic strains can proliferate at the expense of unproblematic strains, resulting in clinical or sub-clinical NE.

Animals suffering from the clinical form show symptoms such as general depression, reluctance to move, and diarrhea, with mortality rates of up to 50%. Infected birds suffer from degenerated mucosa lesions in the small intestines. Even in its “mild”, subclinical form, which often goes unnoticed, the damage to the animals’ intestinal mucosa can result in permanently reduced performance and consequent economic losses for the producer.

Certain predisposing factors have been found to enable the proliferation of pathogenic strains in the gastrointestinal tract. Diet is a key example: the composition of the gut flora is directly linked to feed composition. High inclusion rates of cereals (barley, rye, oats, and wheat) that contain high levels of non-starch polysaccharides (NSPs), high levels of indigestible protein, and inclusion of proteins of animal origin (e.g. fishmeal) have been shown to predispose birds to NE.

A range of diseases (e.g. chicken infectious anemia, Gumboro, and Marek’s disease), but also other factors that have immunosuppressive effects, such as heat or cold stress, mycotoxins, feed changes, or high stocking density, render birds more susceptible to intestinal infections. The single most prominent predisposing factor for the occurrence of NE is the mucosal damage caused by coccidiosis.

Gut health is key to combating necrotic enteritis

To control NE, a holistic approach to optimizing the intestinal health of poultry is needed. It should take into account not only parameters such as diet, hygiene, and stress, but should also make use of innovative tools.

Phytomolecules, also known as secondary plant compounds, are essentially plants’ defense mechanisms against pathogens such as moulds, yeasts, and bacteria. Studies have demonstrated the antimicrobial effects of certain phytomolecules, including against antibiotic-resistant pathogens. Phytomolecules have also been found to boost the production of digestive enzymes, to suppress pro-inflammatory prostaglandins and have antioxidant properties. These features make them a potent tool for optimizing gut health, potentially to the point of replacing AGPs.

Can phytomolecules mitigate the impact of necrotic enteritis?

To study the impact of phytomolecules on the performance of broilers challenged with a NE-causing CP strain, a trial was conducted at a US-based research facility. In this 42-day study, 1050 male day-old Cobb 500 broiler chicks were divided into 3 groups, with 7 replicates of 50 chicks each.

On the first day, all animals were vaccinated against coccidiosis through a live oocyst spray vaccination. The experimental diets met or exceeded the National Research Council requirements, and were fed as crumbles/pellets. On days 19, 20, and 21, all pens, except the negative control group, were challenged with a broth culture of C. perfringens. A field isolate of CP known to cause NE (originating from a commercial broiler operation) was utilized as the challenge organism. On day 21, three birds from each pen were selected, sacrificed, group weighed, and examined for the degree of present NE lesions.

The positive control group received no supplements. The trial group received a synergistic combination of two phytogenic products containing standardized amounts of selected, microencapsulated phytomolecules: an in-feed phytogenic premix (Activo^®, EW Nutrition GmbH) and a liquid complementary feed supplied via the drinking water (Activo® Liquid, EW Nutrition GmbH). The products were given at inclusion rates corresponding to the manufacturer’s baseline antibiotic reduction program recommendations (Figure 1):

Figure 1: Trial design

The trial results indicate that the addition of phytomolecules helps to mitigate the impact of NE on broilers’ performance. The group receiving Activo® and Activo® Liquid showed a better feed conversion (Figure 2) compared to the positive control group (NE challenge, no supplement). Also, better lesion scores were noted for animals receiving phytomolecules (0.7 and 1) than for the positive control group (1.6).

The most significant effect was observed concerning mortality: the group receiving Activo® and Activo® Liquid showed a 50% lower mortality rate than the positive control group (Figure 3). These results clearly indicate that phytomolecules can play an important role in mitigating losses due to NE.

Figure 1: Adjusted FCR

Figure 2: Lesion scores and mortality

Tackling necrotic enteritis in a sustainable way

In an age of AGP-free poultry production, a concerted focus on fostering animals’ gut health is key to achieving optimal performance. This study strongly demonstrates that, thanks to their antimicrobial, digestive, anti-inflammatory and antioxidant properties, phytomolecules effectively support birds’ intestinal health when challenged with NE. The inclusion of Activo® and Activo® Liquid, two phytogenic products designed to synergistically support birds during critical periods, resulted in improved feed conversion, better lesion scores, and 50% lower mortality.

In combination with good dietary, hygiene, and management practices, phytomolecules are therefore a potent tool for reducing the use of antibiotics: including Activo® and Activo® Liquid in their animals’ diets allows poultry producers to reduce the incidence of NE, to mitigate its economic impact in case of outbreaks, and therefore to control NE in a sustainable way.

By A. Bhoyar, T. van Gerwe and S. Regragui Mazili

References

Antonissen, Gunther, Siska Croubels, Frank Pasmans, Richard Ducatelle, Venessa Eeckhaut, Mathias Devreese, Marc Verlinden, Freddy Haesebrouck, Mia Eeckhout, Sarah De Saeger, Birgit Antlinger, Barbara Novak, An Martel, and Filip Van Immerseel. “Fumonisins Affect the Intestinal Microbial Homeostasis in Broiler Chickens, Predisposing to Necrotic Enteritis.” Veterinary Research 46, no. 1 (September 23, 2015): Article 98. doi:10.1186/s13567-015-0234-8.

Moore, Robert J. “Necrotic Enteritis Predisposing Factors in Broiler Chickens.” Avian Pathology 45, no. 3 (May 31, 2016): 275-81. doi:10.1080/03079457.2016.1150587.

Tang, Karen L., Niamh P. Caffrey, Diego B. Nóbrega, Susan C. Cork, Paul E. Ronksley, Herman W. Barkema, Alicia J. Polachek, Heather Ganshorn, Nishan Sharma, James D. Kellner, and William A. Ghali. “Restricting the Use of Antibiotics in Food-producing Animals and Its Associations with Antibiotic Resistance in Food-producing Animals and Human Beings: A Systematic Review and Meta-analysis.” The Lancet Planetary Health 1, no. 8 (November 6, 2017): 316-27. doi:10.1016/s2542-5196(17)30141-9.

Van Immerseel, Filip, Julian I. Rood, Robert J. Moore, and Richard W. Titball. “Rethinking Our Understanding of the Pathogenesis of Necrotic Enteritis in Chickens.” Trends in Microbiology 17, no. 1 (2009): 32-36. doi:10.1016/j.tim.2008.09.005.

Wade, Ben, and Anthony Keyburn. “The True Cost of Necrotic Enteritis.” PoultryWorld. October 09, 2015. Accessed August 19, 2019.

 Source Photo: Aviagen