5 nutrition tips for antibiotic-free poultry production

1. Consider feed form and delivery

Feed form and delivery are nearly as important as the nutrient content of the formulation. If feed form or handling is improper and feed separates, is improperly mixed, or oxidized, the birds will not appreciate the effort that went to develop a balanced diet. A durable pellet or crumble is important to allow all birds to have equal access to a nutritionally complete diet with every bite.

Additionally, if the finished feed or individual ingredients are not stored properly, they may not have the same value that is attributed to them in the formulation process. Other than correct nutrient formulation, three parts of the diet that should be considered are feed additives, mycotoxin contamination, and lipid oxidation.

2. Prevent oxidative stress

The impact of oxidative stress on the intestinal mucosa, immune system, and performance is well-documented across species. Oxidized fat sources reduce the available energy, but equally significant to bird health is the reduction in vitamin availability, resulting in increased oxidative stress for the animal. Protecting the sources of fat and the finished feed is important to spare fat-soluble vitamins, specifically vitamin E.

Oxidized fat can also irritate the intestinal mucosa leading to decreased absorption of nutrients. The process of breaking down macromolecules during digestion and converting them to forms useful for further metabolism is a significant contributor to oxidative stress. The immune system is also a great contributor to oxidative stress. Immune cells use reactive oxygen species to kill pathogens that are phagocytosed.

A large portion of the immune system is located in the GI tract in order to protect the animal from pathogens crossing from the gut into the animal. In addition to being a contributor to oxidative stress, the immune system can be negatively impacted by oxidized feed (Liang et al., 2015). The combination of metabolic and immune activity in the intestines puts it at a high risk of damage from oxidative stress. It is vital to protect fat sources with synthetic or natural antioxidants; reducing the incoming stress from oxidized fat should be a priority to improve poultry health.

3. Mitigate mycotoxin risks

Another risk to bird health and mucosal integrity is mycotoxins. Diets containing mycotoxins may damage the mucosa of the GI tract directly or may damage other organs leading to significant health challenges and decreases in performance. Some mycotoxins or compounds created by fungi can disrupt the intestinal microflora by acting on bacterial cells, as many fungal metabolites are antimicrobial.

The best approach to managing mycotoxins is eliminating them from the system by purchasing high-quality grain and storing it appropriately. It is impossible to completely eliminate all risks of receiving ingredients contaminated with mycotoxins. An internal program should be developed to test the incoming ingredients and finished feed regularly for mycotoxins.

Knowing the challenging ingredient sources may help reduce the risk to highly susceptible birds like Breeders or chicks through dilution in formulation or the addition of toxin binders and/or enzymes. Several toxins may be found in a feed stuff and many of the mycotoxins are synergistic in their deleterious effects (Murugesan et al., 2015). Different binders have varying affinity for different mycotoxins; closely examining the product literature can help to choose the correct product to mitigate risk.

4. Choose optimal additives

Choosing the correct feed additive program for intestinal health, food safety, and growth performance depends on the specific challenges in the complex. When selecting a feed additive that is not FDA approved, it is important to base the decision as much as possible on scientific evidence through peer-reviewed research.

In addition to published data, internal testing within the production system is also helpful to ensure the product matches the local challenge. In a market saturated with “natural” products, it is essential to find a supplier that is trustworthy and is engaged in the success of the complex and health of the birds, not only in selling products. A partnership will be much more successful in the long term than only a buy/sell arrangement.

5. Manage expectations

When considering removing antibiotics from a program, the temptation is to expect natural products to completely replace the efficacy of antibiotics. This is an unreasonable expectation. The success of a transition to ABF production relies on modifying management practices as well. The vast majority of program success is related to attention to the details of husbandry, biosecurity, and sanitation. The remaining opportunity to improve health rests on the additive program.

References

Liang, Fangfang, Shouqun Jiang, Yi Mo, Guilian Zhou, and Lin Yang. “Consumption of Oxidized Soybean Oil Increased Intestinal Oxidative Stress and Affected Intestinal Immune Variables in Yellow-Feathered Broilers.” Asian-Australasian Journal of Animal Sciences 28, no. 8 (2015): 1194–1201. https://doi.org/10.5713/ajas.14.0924.

Murugesan, G.R., D.R. Ledoux, K. Naehrer, F. Berthiller, T.J. Applegate, B. Grenier, T.D. Phillips, and G. Schatzmayr. “Prevalence and Effects of Mycotoxins on Poultry Health and Performance, and Recent Development in Mycotoxin Counteracting Strategies.” Poultry Science 94, no. 6 (2015): 1298–1315. https://doi.org/10.3382/ps/pev075.

Nowadays, the whole world is talking about sustainability. Many efforts aim to maintain our world for future generations, creating a balance between our current needs and those of our children, grandchildren, and great-grandchildren. The right animal nutrition choices play a crucial role in achieving the challenging aim of sustainable animal production.

Sustainability – an old concept now set out in writing

The idea of sustainability is not new. Already the first humans lived sustainably, taking only as much as they needed and the environment could cope with, using all parts of the animals they killed. The German Hannss Carl von Carlowitz (1645-1714) coined the term sustainability in his oeuvre “Sylvicultura oeconomica” to counter a threatening raw material crisis. Wood was one of the most important raw materials. Besides heating, it was used for shipbuilding and mining. This was the reason that extensive areas in Europe were deforested and became deserted. Observing the impending disaster, von Carlowitz ” (1713) stated that only as many trees should be felled as can grow back through planned reforestation, sowing, and planting.

The Brundtland Report (1987), a document created by the World Commission on Environment and Development, is reckoned to be the starting signal for worldwide discussions about sustainability. In 2015, the result of a meeting of 193 members of the United Nations was the Agenda 2030 with 17 sustainable development goals for a “world we want” that should be achieved by 2030.

Sustainable Development Goals (SDG) of the Agenda 2030, fixed by the UN in 2015

How can the feed sector contribute to sustainability?

The animal nutrition industry’s sustainability efforts play into different SDGs, notably no. 2, zero hunger, no. 3, good health and well-being, no. 12, responsible consumption and production, no. 13, climate action, no. 14, life below water, and no. 15, life on land. In addition to the overarching goal of fostering higher animal welfare (cf. Keeling et al., 2019), the feed sector’s measures center on three areas:

1. Optimal use of feed resources, which includes optimizing feed conversion, preserving feed quality, and using alternative ingredients
2. Preserving the environment by reducing ammonia and methane emissions and energy requirements
3. Reducing antibiotics usage to maintain their efficacy for future generations

1.   Make best use of available resources

One of the 17 points on the list of the United Nations is “responsible consumption and production”.  For the feed industry, this means making the most out of available feed sources. Improvements in feed conversion, the maintenance of feed quality, and the use of alternative ingredients are all part of this.

Optimize FCR to utilize the available feed best

The feed conversion rate shows the amount of feed consumed in relation to the outputs produced, such as weight gain, eggs, or milk. The better or lower the feed conversion rate (FCR), the less feed you need to achieve your target, and the higher the yield. Products that improve feed conversion, therefore, can help to save resources.

Good feed conversion or an optimal utilization of nutrients depends on gut health. Only a healthy gut can digest the feed and absorb the nutrients adequately. Hence, products to improve feed conversion often do so by improving gut health.

Phytomolecules: proven to improve feed conversion

Herbs and their active components have been used in human and veterinary medicine for thousands of years to treat digestive tract diseases. Nowadays, products based on phy­tomolecules help improve feed conversion through their digestive, anti-inflammatory, and antimicrobial effects on the intestinal tract.

How do these three characteristics contribute to a better FCR?

• Phy­tomolecules stimulate the secretion of digestive juices and the motility of the gut
• Their antimicrobial effect supports a “healthy” balance in the microbiome, preventing damages of the gut wall by harmful microbes and, therefore, maintaining an optimal nutrient absorption
• Their anti-inflammatory properties also contribute to good nutrient absorption and reduce endogenous nutrient loss

FCR improvements in broilers thanks to ACTIVO found in several studies

As phy­tomolecules are often volatile, EW Nutrition offers encapsulated phytomolecule-based products for the feed (ACTIVO product line). During episodes of elevated enteric challenge, e.g., weaning or following feed change, a liquid solution (ACTIVO LIQUID) can be applied via the waterline.

Enzymes help to make nutrients available

Some feed materials are hard to digest for certain animals. For example, pigs’ digestive systems do not have the enzymes required to break down non-starch polysaccharides (NSPs), such as cellulose, hemicellulose (ß-glucans and xylans), pectins or oligosaccharides. However, pig feed ingredients usually contain these substances.

Besides the non-usability of NSPs, the cage effect is a further problem. Cellulose and hemicellulose, water-insoluble NSPs, encage nutrients such as proteins or digestible carbohydrates. Encaged nutrients cannot be reached by the digestive enzymes and don’t become available to the animal.

Xylanases are available on the market to degrade structural substances in the feed and make them, as well as the nutrients they encaged, available for the organism.

Maintain the quality of your feed materials

Another possibility to save resources is the maintenance of feed quality. Bad weather conditions at harvest or incorrect storage can downgrade feed quality due to the development of molds and their mycotoxins or the oxidation of nutrients. Products mitigating the adverse effects of toxins, acidifiers that reduce microbial load, and antioxidants can help to keep your feed quality on a high level – or to re-establish it.

Mitigate the adverse effects of mycotoxins

Feed materials contaminated with mycotoxins harm animals in different manners and should not be used without further treatment. Mycotoxins are not visible – even if no molds are visible, mycotoxins might be present. Additionally, they are pH- and thermo-stable, meaning that mycotoxins produced in the raw materials on the field remain in the finished feed. As mycotoxins often do not cause apparent, specific symptoms but manifest in decreased performance, feed refusal or lower feed intake, and higher disease susceptibility, it is difficult to notice contamination.

Products such as SOLIS or MASTERSORB contain clay minerals (bentonite and montmorillonite) that adsorb the toxins. MASTERSORB GOLD and MASTERSORB FM also include toxin-adsorbing yeast cell walls and herbal substances to help protect the liver.

Feed spoilage through molds, yeasts, and mycotoxins wastes precious resources

Reduce microbes in the feed with acidifiers

Acidifiers based on organic acids counter harmful microbes in the feed in two ways. Most pathogenic bacteria are susceptible to low pH. The proliferation of, e.g., E. coli, Salmonella, and Clostridium perfringens is minimized at pH < 5 (cf. Fuller 1977). Acidic-tolerant beneficial bacteria such as Lactobacilli or Bifidobacterium, however, survive.

Other than antimicrobial activity, organic acids also cause a significant reduction in ammonia (Eriksen et al., 2014). This finding could be due to a reduction in the microbial deamination of amino acids, which would then be available for absorption, resulting in increased nitrogen digestibility and reduced ammonia excretion, as observed in monogastrics fed organic acids (Pearlin et al., 2020).

The acidifier product lines ACIDOMIX, FORMYCINE, and PRO-STABIL all help protect feed from contamination with pathogenic microorganisms.

Protect the feed’s nutrients from oxidation

The oxidation of nutrients in the feed decreases its nutritional value and, thereby, the value of the whole diet. Fat, proteins, fat-soluble vitamins, pigments, and other biologically active molecules, including sugars and phospholipids, can get oxidized. Metal ions and other pro-oxidative factors can affect the ingredients of the feed during mixing, storage, and feeding. The oxidation of fats and fat-soluble vitamins results in color changes or odors and – this is even more serious – in the production of harmful substances such as aldehydes and ketones. An oxidized feed can lead to oxidative stress in the animals, reduce their immunity, productivity, and livability.

To protect valuable ingredients, the timely addition of effective antioxidants such as STABILON is recommended.

Use alternatives to natural protein sources

Soybeans are an excellent source of protein in animal nutrition. During the last 50 years, soy production has increased from 27 million tons to 269 million tons, causing environmental degradation of forests and savannas (WWF, 2021). The use of alternative protein sources helps protect our environment.

Ruminants partly cover their protein requirements with the help of rumen bacteria. These bacteria can turn nitrogen from urea into bacterial protein, provided they receive enough energy available from carbohydrates. Thanks to its encapsulation, PROTE-N, a feed-grade urea-based nitrogen source, slowly releases nitrogen into the rumen, synchronized with the energy supply. PROTE-N affords producers a degree of independence from soybean protein without compromising nutritional quality.

Reducing soybeans in ruminant feeds helps to lower their environmental impact

2.   Preserve the environment

Animal production generates gases such as ammonia and methane that negatively impact the environment. Measures to reduce these gases help to protect plants, animals, us, and our globe.

Reduce ammonia by improving protein digestion

Besides nitrogen oxides, ammonia is one of the primary sources of nitrogen pollution. Ammonia damages ecological systems through acidification and nutritional oversupply. Fast-growing plants that need high amounts of nitrogen or plants that tolerate low soil pH proliferate, whereas more susceptible plants disappear, decreasing biodiversity. According to Max-Planck-Gesellschaft (2017), reducing ammonia emissions by 50 % could prevent 250.000 deaths caused by fine dust worldwide per year.

Improved protein digestion in animals reduces their ammonia production. Decreasing the intestinal pH through using organic acid-based products such as ACIDOMIX or FORMYCINE is essential for the activation and correct functioning of the enzymes responsible for protein digestion.

Reduce methane, the second most abundant greenhouse gas

Together with CO₂, N₂O, and three fluorinated gases, methane belongs to the greenhouse gases listed in the Kyoto protocol. Being over 25 times more potent than carbon dioxide at trapping heat in the atmosphere, it dramatically affects the earth’s temperature and the climate system (United States Environmental Protection Agency). Methane is a final product of feed fermentation in the rumen and is produced by methanogenic bacteria. Ruminants can produce 250-500 L methane per day (Johnson & Johnson, 1995).

Reducing methane production in ruminants is a critical step towards climate protection. Herbal substances can change the microbiome, leading to improved protein and fiber degradation and reduced methane production (Ku-Vera et al., 2020). ACTIVO PREMIUM is a phy­tomolecules-based product for ruminants that helps reduce their methane emissions.

Energy savings

To preserve the environment, reducing energy needs is also an important topic. Using the surfactant SURF-ACE in the pelletizing process, feed mills can cut 10-15 % of their energy consumption or produce up to 10-15 % higher pellet output without increasing their energy consumption. When moisture is added together with the surfactant, the emulsion of the dietary fat and the added water leads to better general lubrication of the machinery and improved press throughput.

Feed mill efficiency is key to animal nutrition’s carbon footprint

3.   Reduce antibiotic use in animal production to keep this tool effective

Point 3 on the UN’s Agenda 2030 is good health and well-being. For many years, antibiotics, a very effective weapon, have been used to fight bacterial diseases. However, the occurrence of resistance is increasing. One of the reasons is the inappropriate use of antibiotics. These substances are often used preventively or for viral diseases against which they are ineffective. Also, the use of antibiotics as growth promoters at low dosages in animal production strongly contributed to the development of antimicrobial resistance.

Limiting antibiotic use to therapeutic treatment is possible through good farm management and feed supplements that support animals’ gut health, immune systems, and respiratory health. For this purpose, solutions ranging from phy­tomolecules (ACTIVO products, GRIPPOZON) to egg immunoglobulins (GLOBIGEN products, PROTEGG), products mitigating the impact of toxins (MASTERSORB products, SOLIS), beta-glucans/MOS (BGMOS), and acidifiers (ACIDOMIX, FORMYCINE) are available.

The feed sector has the tools to achieve more sustainability!

The animal nutrition industry provides many products to support animal producers in coping with their main challenges, including the shift to more sustainable production practices. Solutions exist to save feed resources, better protect the environment, and keep antibiotic tools effective. As an additional reward, implementing sustainability solutions leads to healthy animals with high performance. Let’s all help to preserve this planet for our next generations!

References

Eriksen, J., Nørgaard, J. V., Poulsen, H. D., Poulsen, H. V., Jensen, B. B., & Petersen, S. O. (2014). Effects of Acidifying Pig diets on emissions of AMMONIA, methane, and sulfur FROM Slurry during storage. Journal of Environmental Quality, 43(6), 2086–2095. https://doi.org/10.2134/jeq2014.03.0108

Fuller, R. (1977). The importance of lactobacilli in maintaining normal microbial balance in the crop. British Poultry Science, 18(1), 85–94. https://doi.org/10.1080/00071667708416332

Johnson, K. A., & Johnson, D. E. (1995). Methane emissions from cattle. Journal of Animal Science, 73(8), 2483–2492. https://doi.org/10.2527/1995.7382483x

Keeling, Linda, Håkan Tunón, Gabriela Olmos Antillón, Charlotte Berg, Mike Jones, Leopoldo Stuardo, Janice Swanson, Anna Wallenbeck, Christoph Winckler, and Harry Blokhuis. “Animal Welfare and the United Nations Sustainable Development Goals.” Frontiers in Veterinary Science 6 (October 10, 2019). https://doi.org/10.3389/fvets.2019.00336.

Ku-Vera, J. C., Jiménez-Ocampo, R., Valencia-Salazar, S. S., Montoya-Flores, M. D., Molina-Botero, I. C., Arango, J., Gómez-Bravo, C. A., Aguilar-Pérez, C. F., & Solorio-Sánchez, F. J. (2020). Role of secondary plant metabolites on enteric methane mitigation in ruminants. Frontiers in Veterinary Science, 7. https://doi.org/10.3389/fvets.2020.00584

Max-Planck-Gesellschaft. (2017, October 27). Reducing manure and fertilizers decreases atmospheric fine particles. Max-Planck-Gesellschaft. https://www.mpg.de/11667398/agricultural-emissions-fine-particulate-matter.

Pearlin, B. V., Muthuvel, S., Govidasamy, P., Villavan, M., Alagawany, M., Ragab Farag, M., Dhama, K., & Gopi, M. (2020). Role of acidifiers in livestock nutrition and health: A review. Journal of Animal Physiology and Animal Nutrition, 104(2), 558–569. https://doi.org/10.1111/jpn.13282

United Nations. (n.d.). How your company can advance each of THE SDGS: UN Global Compact. How Your Company Can Advance Each of the SDGs | UN Global Compact. https://www.unglobalcompact.org/sdgs/17-global-goals.

United States Environmental Protection Agency. (n.d.). Importance of methane. EPA. https://www.epa.gov/gmi/importance-methane.

von Carlowitz, H. C. (1713). Sylvicvltvra oeconomica, oder, Hausswirthliche Nachricht und Naturmässige Anweisung zur Wilden BAŬM-ZŬCHT: Nebst gründlicher darstellung, wie Zu FÖRDERST durch Göttliches Benedeyen Dem allenthalben und insgemein einreissenden Grossen Holtz-mangel: Vermittelst Säe-pflantz- und Versetzung Vielerhand Bäume zu prospiciren …: Worbey zugleich eine Gründliche nachricht von den in Churfl. Sächss. Landen gefundenen Turff Dessen Naturliche beschaffenheit, Grossen NÜTZEN, Gebrauch und nutzlichen verkohlung, Aus Liebe Zu BEFÖRDERUNG des Algemeinen Bestens beschrieben. Verlegts Johann Friedrich Braun.

World Wildlife Fund. (2021). Soja – die Nachfrage steigt. WWF Startseite. https://www.wwf.de/themen-projekte/landwirtschaft/produkte-aus-der-landwirtschaft/soja/.

The threat of molds and yeasts in animal feed

Yeasts and molds can have both positive and negative effects on products consumed by animals and humans. On the one hand, yeasts are used to produce fermented products, such as bread, wine, and beer. On the other hand, yeasts and molds promote the spoilage of raw materials, food, and feeds (Lowes et al., 2000). Molds are among the most potent food and feed spoilers. They can be very resilient to environmental stress, which is a concern in climate change scenarios (Perrone et al., 2020) and enables them to withstand feed preservation measures (Punt et al., 2020).

Several hundred species of molds and yeasts can invade a large variety of raw materials and feeds. They show an easy adaptation to different environments; for instance, they can grow and reproduce in media with pH levels ranging from 2 to above 9 (Tournas et al., 2001). However, the majority of yeasts and molds require free oxygen to grow and thrive.

Excess moisture, high water activity, and high temperatures in feedstuffs are the main mold growth factors that concern the feed industry (Mohapatra et al., 2017).  At storage, grains’ moisture content should not exceed 13%, and the water activity of raw materials, feedstuffs, and finished feed should be maintained below 0.8 (Dijksterhuis et al., 2019).  Controlling these points contributes to preventing the growth of most pathogens and undesirable microorganisms.

Mold growth reduces the nutritional value of feed, which affects animal health and performance

The microbiology of molds and how they affect the feed

The microbial growth dynamic of grain storage depends on several factors, including the harvest season, grain temperature and moisture content, as well as the type of facility and its environment. For instance, in some areas, grains are harvested at the beginning of the cold season and stored through the following warm season. Storage molds constitute a significant threat to the quality of these raw materials, especially during the warm months, when the stored grains may become hotter than the surrounding environment. This leads to condensation, which increases moisture and water activity. Molds easily thrive in these conditions.

Storage molds reduce the nutritional and commercial value of grains and feeds. For grains, their commercial value decreases when the appearance of kernels changes in a manner recognized by the grain industry as kernel damage. The chemical composition of feeds may deteriorate due to enzymatic actions, resulting in a loss of nutrients (energy, vitamins) and the production of free fatty acids and other unwanted by-products (Reed et al., 2007).

Extensive research has established the factors that influence mold-induced deterioration during grain storage and which management strategies are required:

• Moisture content and water activity (a function of the temperature, moisture content, and substrate) – Microorganisms have a limiting water activity below which they cannot grow; therefore, drying the grains below that critical level is part of an effective mold control strategy (Mannaa & Kim, 2017).
• Temperature – Grain-contaminating molds thrive in tropical regions, where high temperature and humidity conditions predominate. In general, molds are inactive if the grains are stored below 20 °C (Mousa et al., 2013). However, the temperature of stored grains increases as molds begin to grow in the warmer and/or wetter parts of the grain/feed mass and feed, and heat is generated due to respiration, accelerating the deterioration rate. Moreover, the presence of a temperature gradient in the feedstuffs causes air to move, accelerating the transfer of moisture to cooler grain (Mannaa & Kim, 2017).
• Grain quality, including previous storage conditions, insect infestation, presence of broken kernels, and impurities – When grain is too warm, the rate of insects’ breeding is higher (they respond to higher temperatures), the grain contains more humidity and may carry fungal spores. Broken kernels are an easier target for mold and insect infestations than whole ones, increasing the possibility of spoilage (Marcos Valle et al., 2021).
• Duration of storage, management, and aeration influence the oxygen and carbon dioxide concentration in the grain mass, which plays a role in mold growth (Marcos Valle et al., 2021).

The consequences of storage deterioration include:

• worse organoleptic properties (aspect, texture, taste, and aroma) of grains and feeds
• more kernel damage,
• higher fat acidity,
• slight increase in protein content as non-protein constituents are consumed by mold respiration, causing
• lower energy value of the grain/feed (Reed et al., 2007), and
• lower content of vitamins A, B1, D3, E, and K.

Molds and mycotoxins: a toxic relationship for animal health

Beyond their negative impact on feed quality, some fungal genera such as Aspergillus, Penicillium, Alternaria, and Fusarium can produce mycotoxins, secondary metabolites that have toxic effects on humans and animals (Greco et al., 2015). Roughly 60% of raw materials produced for agriculture purposes worldwide are estimated to be contaminated by fungi and mycotoxins (Eskola et al., 2020). Mycotoxins can induce toxic, carcinogenic, and mutagenic reactions even at low concentrations. Their presence in the final feed is a sign of alert as, usually, these metabolites are resistant to technological treatments. Thus, it is important to stop them from entering the feed production chain (Leyva Salas et al., 2017).

Feed-contaminating Fusarium species produce mycotoxins such as trichothecenes, zearalenone, and Fumonisin.

Organic acids: Unrivaled in preventing feed spoilage

It is crucial to reduce the feed losses and improve animal health by controlling fungal contamination at all stages of the feed production chain: from pre-harvest strategies on the field to post-harvest management during storage and even at feed processing. Throughout these processes, producers can apply different management practices. For instance, in field crops, fungal growth can be prevented through crop rotation and tillage; the use of fungicides is a later measure when mold presence exceeds critical levels.

Post-harvest management of grains and their by-products includes drying and storage management through moisture and temperature monitoring and aeration programs. Other spoilage-prevention measures include good hygiene practices and thermal treatments in feed production. However, feed producers and farmers face limitations in applying and linking such measures to tackle the occurrence of these undesirable pathogens (Dijksterhuis et al., 2019).

Certain organic acids, such as propionic, sorbic, benzoic, and acetic acids, have proven effective in preventing mold growth and feed spoilage. These organic acids are used globally now, not only for improving animal nutrition but also for supporting animal health (Dijksterhuis et al., 2019).

Pro-Stabil BSL is a product that harnesses the feed preservation effects of organic acids and combines them with surfactants. This means that it can offer a strong yeast and mold inhibition while maintaining the moisture in feed, thus reducing the risk of microbial challenges while prolonging the shelf life of feedstuffs and compound feeds.

Trial results: Pro-Stabil BSL is a great tool to reduce mold growth and manage moisture

Pro-Stabil BSL contains a synergistic blend of organic acids and a surfactant that leads to

» Improved moisture dispersion in the feed

» Increased water retention (reduced water activity)

» Improved anti-mold agent dispersion in the feed and grain

Trial results show a significant decrease in mold growth when Prostabil BSL was added to compound feed. In addition, when moisture was added at 2%, moisture from the environment was also observed, but the mold counts still decreased (Figure 1).

Figure 1: Effects of Pro-Stabil BSL with addition of 2 % moisture on feed quality indicators

When adding Pro-Stabil BSL to animal feed, the following benefits can be expected:

• Reduction and prevention of mold growth and recontamination
• Improved moisture management
• Improved feed mill efficiency production
• Improved microbiological quality of grains and feed
• Shrinkage management by increasing moisture in feed with no risk of mold development
• Reduced water dissipation

Mold growth can lead to sensory defects in feed and reduce its nutritional value. It can also harm animals through the production of mycotoxins. Pro-Stabil BSL offers a safe solution that is also easy to handle. Using the preservative properties of organic acids, Pro-Stabil BSL helps to reduce feed spoilage and its associated effects on animal health and performance.

References

Dijksterhuis, Jan, Martin Meijer, Tineke van Doorn, Jos Houbraken, and Paul Bruinenberg. “The Preservative Propionic Acid Differentially Affects Survival of Conidia and Germ Tubes of Feed Spoilage Fungi.” International Journal of Food Microbiology 306 (2019): 108258. https://doi.org/10.1016/j.ijfoodmicro.2019.108258.

Eskola, Mari, Gregor Kos, Christopher T. Elliott, Jana Hajšlová, Sultan Mayar, and Rudolf Krska. “Worldwide contamination of food-crops with mycotoxins: Validity of the widely cited ‘FAO estimate’ of 25%.” Critical Reviews in Food Science and Nutrition 60, no. 16 (2020): 2773-2789. https://doi.org/10.1080/10408398.2019.1658570

Greco, Mariana, Minna Kemppainen, Graciela Pose, and Alejandro Pardo. “Taxonomic Characterization and Secondary Metabolite Profiling Of Aspergillus Section Aspergillus Contaminating Feeds And Feedstauffs.” Toxins 7, no. 9 (2015): 3512–37. https://doi.org/10.3390/toxins7093512.

Harein, P., & Meronuck, R. (1995). Stored grain losses due to insects and molds and the importance of proper grain management. In V. Krischik, G. W. Cuperus, & D. Galliart (Eds.), Stored product management (pp. 29e31). Oklahoma Cooperative Extension Service Publication. E-912.

Leyva Salas, Marcia, Jérôme Mounier, Florence Valence, Monika Coton, Anne Thierry, and Emmanuel Coton. “Antifungal Microbial Agents for Food Biopreservation—a Review.” Microorganisms 5, no. 3 (2017): 37. https://doi.org/10.3390/microorganisms5030037.

Lowes, K. F., C. A. Shearman, J. Payne, D. MacKenzie, D. B. Archer, R. J. Merry, and M. J. Gasson. “Prevention of Yeast Spoilage in Feed and Food by the Yeast Mycocin Hmk.” Applied and Environmental Microbiology 66, no. 3 (2000): 1066–76. https://doi.org/10.1128/aem.66.3.1066-1076.2000.

Mannaa, Mohammed, and Ki Deok Kim. “Influence of temperature and Water activity on Deleterious fungi AND Mycotoxin production during grain storage.” Mycobiology 45, no. 4 (2017): 240–254. https://doi.org/10.5941/myco.2017.45.4.240.

Marcos Valle, F. J., Castellari, C., Yommi, A., Pereyra, M. A., & R. Bartosik. “Evolution of grain microbiota during hermetic storage of corn (zea mays l.).” Journal of Stored Products Research 92 (2021): 101788. https://doi.org/10.1016/j.jspr.2021.101788.

Mohapatra, D., Kumar, S., Kotwaliwale, N., and K. K. Singh. “Critical factors responsible for fungi growth in stored food grains and non-Chemical approaches for their control.” Industrial Crops and Products 108 (2017): 162–182. https://doi.org/10.1016/j.indcrop.2017.06.039.

Mousa, W., Ghazali, F. M., Jinap, S., Ghazali, H. M., and S. Radu. “Modeling growth rate and assessing AFLATOXINS production by Aspergillus flavusas a function of Water activity and temperature on polished and brown rice.” Journal of Food Science 78, no. 1 (2013). https://doi.org/10.1111/j.1750-3841.2012.02986.x.

Perrone G, Ferrara M, Medina A, Pascale M, and N. Magan. “Toxigenic Fungi and Mycotoxins in a Climate Change Scenario: Ecology, Genomics, Distribution, Prediction and Prevention of the Risk.” Microorganisms 8, no. 10 (2020): 1496. https://doi.org/10.3390/microorganisms8101496.

Punt, Maarten, Tom van den Brule, Wieke R. Teertstra, Jan Dijksterhuis, Heidy M.W. den Besten, Robin A. Ohm, and Han A.B. Wösten. “Impact of Maturation and Growth Temperature on Cell-size Distribution, Heat-Resistance, Compatible Solute Composition and Transcription Profiles of Penicillium Roqueforti Conidia.” Food Research International 136 (2020): 109287. https://doi.org/10.1016/j.foodres.2020.109287.

Reed, Carl, Stella Doyungan, Brian Ioerger, and Anna Getchell. “Response of Storage Molds to Different Initial Moisture Contents of Maize (Corn) Stored AT 25°C, and Effect on Respiration Rate and Nutrient Composition.” Journal of Stored Products Research 43, no. 4 (2007): 443–58. https://doi.org/10.1016/j.jspr.2006.12.006.

Tournas, Valerie, Michael E. Stack, Phillip B. Mislivec, Herbert A. Koch, and Ruth Bandler. “Bacteriological Analytical Manual Chapter 18: Yeasts, Molds and Mycotoxins.” U.S. Food and Drug Administration. April 2001. https://www.fda.gov/food/laboratory-methods-food/bam-chapter-18-yeasts-molds-and-mycotoxins.

VISBEK, GERMANY, 23 August – Bad news for feed producers: after supply chain disruptions and raw material unavailability, now weather-related challenges in Europe will most likely affect this year’s crop quantity and quality. Cold temperatures, heatwaves, tornados, and hailstorms are expected to adversely affect the quality and quantity of the harvest.

The moisture brought by the rainfalls is generally expected to affect the quality of the crops. The torrential rains in France, Germany, etc. have darkened Central and Western farmers’ prospects: while the quantity may be there, the quality of wheat and corn is under question. Sprouting grains, diseased crops, and fungi may dampen the optimism brought by numbers alone.

Further east, droughts have posed different issues. Still, countries such as Romania and Bulgaria seem to have weathered the challenges somewhat better and are seeing YoY increases in their wheat and corn crop output.

In Great Britain, rainfall has not caused dramatic drops in crop output but has nevertheless greatly increased mycotoxin risk up to a “moderate to high” level.

Depending on the type of mycotoxin, weather challenges and storage conditions are the most common contributors to severe infestation. This year’s intemperate weather has, in fact, been ideal for a large spectrum of fungi. Fungal risks can be calculated at the two critical times: at flowering and at harvest and baling, when there is an increased risk of storage molds and mycotoxin production.

Preliminary analysis shows Europe’s wheat crops at potential risk of DON, as well as potentially Aflatoxin and Fumonisin infestation and more. Specialists continue to collect and monitor harvest results and adjust recommendations; however, we can definitely expect the presence of moderate, if not quite high levels of mycotoxin risk this year.

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

What is your most crucial key feed performance indicator? We posted this question on an online professional platform and got more than 330 answers from professionals in the industry:

• 55 % of the respondents considered feed efficiency or feed conversion rate (FCR) the key indicator, and
• 35 % listed feed cost / kg produced as their most important indicator.

As feed represents 60-70 % of the total production costs, feed efficiency has a high impact on farm profitability – especially in times of high feed prices. Furthermore, for the meat industry, an optimal FCR is essential for competitiveness against other protein sources. Finally, for food economists, feed efficiency is connected to the optimal use of natural resources (Patience et al., 2015).

In this article, we explain the factors that influence feed efficiency and show options to support animals in optimally utilizing the feed – directly improving the profitability of your operation.

How to measure the feed conversion rate

The FCR shows how efficiently animals utilize their diet for maintenance and net production. In the case of fattening animals, it is meat production; for dairy cows, it is milk, and for layers, it is egg mass (kg) or a specific egg quantity.

The feed conversion rate is the mathematical relation obtained by dividing the amount of feed the animal consumed by the production it provided. The FCR is an index for the degree of feed utilization and shows the amount of feed needed by the animal to produce one kg of meat or egg mass, or, e.g., 10 eggs.

When comparing the FCRs of different groups of animals (e.g., from different houses or farms), some considerations are important:

• Feed consumed is not feed disappeared: Due to differences in feeder design and feeder adjustment, these two values can differ by 10-30 %. If FCR is calculated for economic purposes, the wasted feed must be included, as it causes costs and must be paid by the farmer. However, if FCR is calculated for scientific purposes (e.g., a performance trial), only the feed consumed should be included.
• Even if they are same-aged animals, individuals or groups differ in weight. Hence, they have different requirements for maintenance and also diverging quantity left for production. To avoid mistakes, weight-corrected FCR can be used.
• Nutrient utilization also depends on genotype and sex; thus, comparisons should consider these factors as they also influence weight gain and body composition (Patience et al., 2015).

Many factors influence the FCR

There are internal and external factors that influence feed efficiency. Internal factors originate in the animal and include genetics, age, body composition, and health status. In contrast, external factors include feed composition, processing, and quality, as well as the environment, welfare enrichment, and social aspects.

1. Species

Different species have different body sizes and physiology and, therefore, vary in their growth and maintenance requirements, impacting their efficiency in converting the feed.

Table 1: FCRs of different species

Compared to terrestrial animals, for example, fish and other aquatic animals have a low FCR. Being poikilothermic (animals whose body temperature ranges widely), they don’t spend energy on maintaining their body temperature if the surrounding water is within their optimal range. As they are physically supported by water, they also need less energy to work against gravity. Furthermore, carnivorous fish are offered highly digestible, nutrient-dense feed, which lowers their requirements in quantity. Omnivorous fish, on the other hand, also consume feedstuffs not provided by the producer (e.g., algae and krill), which is not considered in the calculation. Broilers are the only farm animals achieving a similar FCR.

2. Sex, age, and growth phase

Sex determines gene expression related to the regulation of feed intake and nutrient utilization. Males have a better feed conversion and put on more lean meat than females and castrates, which grow slower and easier run to fat.

Young animals have a fast growth rate and are offered nutritionally dense feed; hence, their FCR is lower. When the animal grows and gains weight, its energy requirement for maintenance increases and its growth rate and the feed nutrient density diminish.

Table 2: FCR during different life phases of pigs (based on Adam and Bütfering, 2009)

3. Health and gut health

Health decisively impacts feed conversion. An animal that is challenged by pathogens reduces its feed intake and, thus, decreases growth. Additionally, the body needs energy for the immune defense, the replacement of damaged or lost tissue, and heat production, in case of fever. As many immune components are rich in protein, this is the first nutrient to become limited.

An imbalance in the gut microbiome also impacts feed conversion: pathogenic microorganisms damage tissues, impair nutrient digestion and absorption, and their metabolic products are harmful. Furthermore, pathogens consume nutrients intended for the host and continue to proliferate at its expense.

4. Environment

The environment influences the way the animals spend their maintenance energy. According to Patience (2012), when a 70 kg pig is offered feed ad libitum, 34 % of the daily energy is used for maintenance. For each °C below the thermoneutral zone, an additional 1.5% of feed is needed for maintenance. In heat stress, each °C above the optimum range decreases feed intake by 2%. Therefore, the feed needs to be denser to fulfill the requirement, or the animal will lose weight. Social stress also influences animal performance, especially chronic stress situations. Keeping the animals in their thermoneutral zone and mitigating the impact of stressors means more energy can go towards performance.

5. Feed quantity, composition, and quality

The feed is the source of nutrients animals convert into production. So, it’s natural that its quality and composition, and the availability of nutrients affect feed efficiency.

Better FCR by increasing nutrient density and digestibility

Higher energy content in the diet and better protein digestibility improve FCR. Saldaña et al. (2015) assert that increasing the energy content of a diet led to a linear decrease of the average daily feed intake but improved FCR quadratically. The energy intake by itself remained equal. However, these diet improvements also increase costs, and a cost-benefit analysis should be conducted.

Feed form and particle size play an important role

Feed processing can improve nutrient utilization. Particle size, moisture content, and whether the feed is offered as pellets or mash influence feed efficiency. Reducing the particle size leads to a higher contact surface for digestive enzymes and higher digestibility. Chewning et al. (2012) tested the effect of particle size and feed form on FCR in broilers. They found that pellet diets enable better FCRs than mash diets – one reason is the lower feed waste, another one the smaller feed particle size in the pelleted feed. Comparing the different tested mash diets, the birds receiving feed with a particle size of 300 µm performed better than the birds getting a diet with 600 µm particles.

Richert and DeRouchey (2015) show that pigs’ feed efficiency improved by 1.3 % for every 100 µm when the particle size was reduced from 1000 µm to 400 µm , as the contact surface for the digestible enzymes increased. In weaning piglets of 28-42 days, the increase of particle size from 394 µm to 695 µm worsened FCR from 1.213 to 1.245 (Almeida et al., 2020). There is a flipside to smaller particle size as well, however: high quantities of fines in the diet can lead to stomach ulceration in pigs (Vukmirović et al., 2021).

Non-starch polysaccharide (NSP)-rich cereals worsen FCR

The carbohydrates in feedstuffs such as wheat, rye, and barley are not only energy suppliers, and if not managed well, the inclusion of these raw materials can deteriorate feed conversion. Vegetable structural substances such as cellulose, hemicellulose, or lignin (e.g., in bran), are difficult or even impossible to utilize as they lack the necessary enzymes.

Figure 1: Contents of arabinoxylan and ß-glucan in grain (according to Bach Knudsen, 1997)

Additionally, water-soluble NSPs (e.g., pectins, but also ß-glucans and pentosans) have a high water absorption capacity. These gel-forming properties increase the viscosity of the digesta. High viscosity reduces the passage rate and makes it more difficult for digestive enzymes and bile acids to come into contact with the feed components. Also, nutrients’ contact with the resorptive surface is reduced.

Another disadvantage of NSPs is their “cage effect.” The water-insoluble NSPs cellulose and hemicellulose trap nutrients such as proteins and digestible carbohydrates. Consequently, again, digestive enzymes cannot reach them, and they are not available to the organism.

Molds and mycotoxins impair feed quality, but also animal health

Molds reduce the nutrient and energy content of the feed and negatively impact feed efficiency. They are dependent on active water in the feed and feed ingredients. Compared to bacteria, which need about 0.9-0.97 Aw (active water), most molds require only 0.86 Aw.

Table 3: Comparison of 28-day-old chicks performance fed not-infested and molded corn

Besides spoiling raw materials and feed and reducing their nutritional value, molds also produce mycotoxins which negatively impact animal health, including gut health. They damage the intestinal villi and tight junctions, reducing the surface for nutrient absorption. In a trial with broiler chickens, Kolawole et al. (2020) showed a strong positive correlation between the FCR and the exposure to different mycotoxins. The increase in levels of toxin mixtures resulted in poor FCR. Williams and Blaney (1994) found similar results with growing pigs. The animals received diets containing 50 % and 75 % of corn with 11.5 mg nivalenol and 3 mg zearalenone per kg. The inclusion of contaminated corn led to a deterioration of feed efficiency from 2.45 (control) to 3.49 and 3.23.

Oxidation of fats also affects feed quality

DDGS (distiller’s dried grains with solubles), by-products of corn distillation processes, are often used as animal feed, especially for pigs. The starch content is depleted in the distillation process and thus removed. The fat, however, is concentrated, and DDGS reach a similar energy content as corn.

Pigs also receive fats from different sources (e.g., soybean or corn oil, restaurant grease, animal-vegetable blends), especially in summer. Due to heat, the animals eat less, so increasing energy density in the feed is a possibility to maintain the energy intake.  The high fat content, however, makes these feeds susceptible to oxidation at high temperatures.

The oxidation of feedstuffs manifests in the rancidity of fats, destruction of the fat-soluble vitamins A, D, and E, carotenoids (pigments), and amino acids, leading to a lower nutritional value of the feed.

Use adequate supplements to enhance FCR

The feed industry offers many solutions to improve the FCR for different species. They usually target the animal’s digestive health or maintain/enhance feed quality, including increasing nutrient availability.

1. Boost your animals’ gut health

Producers can improve gut health by preventing the overgrowth of harmful microorganisms and by mitigating the effects of harmful substances. For this purpose, two kinds of feed additives are particularly suitable: phytomolecules and products mitigating the impact of toxins and mycotoxins.

Phytomolecules help stabilize the balance of the microbiome

By preventing the proliferation of pathogens, phytomolecules help the animal in three ways:

1. They prevent pathogens from damaging the gut wall
2. They deter and mitigate inflammation
3. By inhibiting the overgrowth of pathogens, they promote better nutrient utilization by the animal

Only a healthy gut can optimally digest feed and absorb nutrients.

In trials testing the phytogenic Activo product range, supplemented animals showed the following FCR improvements compared to non-supplemented control groups (Figure 2).  Note that phy­tomolecules also have a digestive effect that contributes to the FCR improvements:

Figure 2: FCR improvements for animals receiving Activo

Products mitigating the adverse effects of toxins

Both mycotoxins and bacterial toxins negatively impact gut health. Mycotoxins are ingested with the feed; bacterial toxins appear when certain bacteria proliferate in the gut, e.g., gram-negative bacteria releasing LPS or Clostridium perfringens producing NetB and Alpha-toxin.

Products that mitigate the harmful effects of toxins help to protect gut health and maintain an optimal feed efficiency, as shown with a trial conducted with Mastersorb Gold:

Table 4: Trial design, the impact of Mastersorb Gold on broilers challenged with zearalenone and DON-contaminated feed

Figure 3: Average FCR for broilers, with or without zearalenone and DON challenge, with or without Mastersorb Gold supplementation

2. Improve nutrient utilization

Maximum use of the nutrients contained in the feed can be obtained with the help of feed additives that promote digestion. Targeting the animal, selected phytomolecules are used for their digestive properties. Focusing on the feed, specific enzymes can unlock nutrients and thus improve feed efficiency.

Phytomolecules support the animal’s digestive system

Phytomolecules promote optimal digestion and absorption of nutrients by stimulating the secretion of digestive juices, such as saliva or bile, enhancing enzyme activity, and favoring good GIT motility (Platel and Srinivasan, 2004). FCR improvements thanks to the use of a phy­tomolecules-based product (Activo) are shown in figure 2.

Enzymes release more nutrients from feed

Enzymes can degrade arabinoxylans, for example. Arabinoxylans are the most common NSP fraction in all cereals – and are undigestible for monogastric animals. Enzymes can make these substances available for animals, allowing for complete nutrient utilization.  Additionally, nutrients trapped due to the cage effect are released, altogether increasing the energy content of the diet and improving FCR.

3. Be proactive about preserving feed quality

The quality of feed can deteriorate, for instance, when nutrients oxidize, or mold infestation occurs. Oxidation by-products promote oxidative stress in the intestine and may lead to tissue damage. Molds, in turn, take advantage of the nutrients contained in the feed and produce mycotoxins. Both cases illustrate the importance of preventing feed quality issues. Feed additives such as antioxidants and mold inhibitors mitigate these risks.

Antioxidants prevent feed oxidation

Antioxidants scavenge free radicals and protect the feed from spoilage. In animals, they mitigate the adverse effects of oxidative stress. Antioxidants in pig nutrition can stabilize DDGS and other fatty ingredients in the feed, maintaining nutrient integrity and availability. Figure 4 shows the FCR improvement that a producer in the US obtained when using the antioxidant product Santoquin in pork finisher diets containing 30% DDGS.

Figure 4: FCR improvement in pigs receiving Santoquin (trial with a Midwest pork producer)

In DDGS-free diets, which are more common in poultry production, antioxidants also help optimize FCR, as shown by the results of a comprehensive broiler field study in 2015 (figure 5).

Figure 5: FCR in broilers receiving Santoquin, compared to a non-supplemented control group

Inhibiting molds and keeping feed moisture

To round off the topic of feed quality preservation, one should consider mold inhibitors, which also play an essential role. Used at the feed mill, these products blend two types of ingredients with their different modes of action: surfactants and organic acids. Surfactants bind active water so that the moisture of the feed persists, but fungi cannot survive. Organic acids, on the other hand, have anti-fungal properties, directly acting against molds. Both actions together prevent the reduction of energy in the feed, keeping feed efficiency at optimal levels.

Conclusion

The improvement of feed efficiency ranks as one of the most, if not the most, critical measures to cope with rising feed costs. By achieving optimal nutrient utilization, producers can make the most out of the available raw materials.

The feed industry offers diverse solutions to support animal producers in optimizing feed efficiency. Improving gut health, mitigating the negative impact of harmful substances, and maintaining feed quality are crucial steps to achieving the best possible FCR and, hence, cost-effective animal production.

References

Adam, F., and L. Bütfering. “Wann Müssen Meine Schweine an Den Haken?” top agrar. top agrar online, October 1, 2009. https://www.topagrar.com/schwein/aus-dem-heft/wann-muessen-meineschweine-an-den-haken-9685161.html.

Almeida, Leopoldo Malcorra, Vitor Augusto Zavelinski, Katiucia Cristine Sonálio, Kariny Fonseca da Silva, Keysuke Muramatsu, and Alex Maiorka. “Effect of Feed Particle Size in Pelleted Diets on Growth Performance and Digestibility of Weaning Piglets.” Livestock Science 244 (2021). https://doi.org/10.1016/j.livsci.2020.104364.

Chewning, C.G., C.R. Stark, and J. Brake. “Effects of Particle Size and Feed Form on Broiler Performance.” Journal of Applied Poultry Research 21, no. 4 (2012): 830–37. https://doi.org/10.3382/japr.2012-00553.

Gaines, A. M., B. A. Peerson, and O. F. Mendoza. “Herd Management Factors That Influence Whole Feed Efficiency.” Essay. In Feed Efficiency in Swine, edited by J. Patience, 15–39. Wageningen Academic, 2012.

Kolawole, Oluwatobi, Abigail Graham, Caroline Donaldson, Bronagh Owens, Wilfred A. Abia, Julie Meneely, Michael J. Alcorn, Lisa Connolly, and Christopher T. Elliott. “Low Doses of Mycotoxin Mixtures below EU Regulatory Limits Can Negatively Affect the Performance of Broiler Chickens: A Longitudinal Study.” Toxins 12, no. 7 (2020): 433. https://doi.org/10.3390/toxins12070433.

Patience, J. F. “The Influence of Dietary Energy on Feed Efficiency in Grow-Finish Swine.” Essay. In In Feed Efficiency in Swine, edited by J. Patience, 15–39. Wageningen Academic, 2012.

Patience, John F., Mariana C. Rossoni-Serão, and Néstor A. Gutiérrez. “A Review of Feed Efficiency in Swine: Biology and Application.” Journal of Animal Science and Biotechnology 6, no. 1 (2015). https://doi.org/10.1186/s40104-015-0031-2.

Platel, K., and K. Srinivasan. “Digestive Stimulant Action of Spices: A Myth or Reality?” Indian J Med Res, pp 167-179 119 (May 2004): 167–79. http://www.ncbi.nlm.nih.gov/pubmed/15218978

Richert, B. T., and J. M. DeRouchey. “Swine Feed Processing and Manufacturing.” Pork Information Gateway, September 14, 2015. https://porkgateway.org/resource/swine-feed-processing-and-manufacturing/.

Saldaña, B., P. Guzmán, L. Cámara, J. García, and G.G. Mateos. “Feed Form and Energy Concentration of the Diet Affect Growth Performance and Digestive Tract Traits of Brown-Egg Laying Pullets from Hatching to 17 Weeks of Age.” Poultry Science 94, no. 8 (2015): 1879–93. https://doi.org/10.3382/ps/pev145.

Vukmirović, Đuro, Radmilo Čolović, Slađana Rakita, Tea Brlek, Olivera Đuragić, and David Solà-Oriol. “Importance of Feed Structure (Particle Size) and Feed Form (Mash vs. Pellets) in Pig Nutrition – A Review.” Animal Feed Science and Technology 233 (2017): 133–44. https://doi.org/10.1016/j.anifeedsci.2017.06.016.

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

In the last few months, the prices for feed grains and oilseeds such as soybeans have been climbing to multi-year heights. In part, this can be explained by high corn purchases by China and increasing export duties in Russia. The most significant cause, however, are weather events in producing countries: Just in the last year, droughts in the USA, Canada, and France raised the price of wheat by 40 %, the worst La Niña climate event in 91 years and the drought in China’s biggest corn-growing area made corn about 100 % more expensive, and soybeans carry a 40 % higher price tag because of dry conditions in Argentina.

These events are a stark reminder that for global agriculture climate change impacts are already a reality. High feed costs are an enormous challenge for the whole agricultural sector and sustainable strategies need to be adopted to enable a more efficient use of resources, both in the short and long term. This article explores possibilities to cope with the current situation. Through understanding the positions of farmers, integrators and feed millers and using targeted feed additive solutions, we can achieve a responsible use of resources that makes animal production more resilient to feed price increases.

Feed cost issues? Always start with this

The first question producers need to ask themselves is always if there is any step in the production process that could be done more effectively. Similar to biosecurity programs, the basic steps seem self-evident, but to consistently implement them in the complex on-farm reality requires regular checks.

Feeding as “exactly” as possible

In case of high prices, the feed raw materials should be used as responsibly as possible:

• Protein and energy content (but also other components, such as minerals and vitamins) must meet the requirements of the animals – age and production phase are decisive for the calculations.
• Given variations in raw material quality, it is important to exactly determine nutrient contents to avoid over- and under-supply. For this purpose, technologies like the near-infrared spectroscopy (NIR) can be used.

Using locally available sources

In the initial stages of price hikes, it is often possible to resort to locally available sources, e.g., using sunflower or flaxseed meal to replace soybeans. Unfortunately, with increasing demand, these feed materials will usually become more expensive as well, and might not be suitable alternatives anymore. In general, however, it is worth using a maximum of local ingredients: they are often cheaper and less susceptible to transport and trade difficulties.

Feed additive solutions: use what is available in the best possible way

Once these first measures are exhausted, it is time to draw on industry solutions to derive maximum value out of the available feed ingredients. Let us consider four approaches that improve feed conversion and feed quality, adjust feed composition, and optimize feed production processes.

1.   A critical goal: improving the feed conversion rate

The most direct way to better utilize feed is to improve the animals’ feed conversion rate, with the help of the right supplements. Different product groups contribute to this aim in different ways.

1.1 Phytomolecules fight on different fronts

Phytomolecules are well-known for their antimicrobial effects against pathogenic bacteria (Zhai et al., 2018). Phy­tomolecules shift the balance of the microbiome towards the beneficial side (eubiosis instead of dysbiosis) and promote gut health. A healthy gut is able to digest the feed and absorb the nutrients in an efficient way.

Another value of phy­tomolecules is their digestive effect. They stimulate the secretion of saliva, gastric juice and digestive enzymes, and favor an adequate gastrointestinal motility, which leads to improved nutrient utilization (Jones, 2001; Mendel et al., 2017).

In trials testing the phytogenic Activo product range, supplemented animals showed the following FCR improvements compared to non-supplemented control groups (Figure 1):

Figure 1: FCR improvements for animals receiving Activo

1. 2 Enzymes improve nutrient availability

Even a corn-soybean meal diet is not fully digestible for monogastric animals. However, when feed prices increases, producers likely need to include more alternative ingredients in the diet that are much less digestible. Typically, these ingredients are rich in antinutritional factors such as non-starch polysaccharides (NSPs), which can cause detrimental effects on gut health.

Another disadvantage of NSPs is their “cage effect”. The water-insoluble NSPs cellulose and hemicellulose trap nutrients such as proteins and digestible carbohydrates. Consequently, digestive enzymes cannot reach them and they are not available to the organism.

Here is the point of attack for enzymes that enable a complete nutrient utilization: Making these substances available for the animals increases the energy content of the diet and, in the end, improves FCR. An example for laying hens receiving wheat-based diets can be found in Figure 2: Axxess XY, a xylanase, significantly improved feed utilization by the hens.

Figure 2: FCR in layers receiving Axxess XY, compared to control group (kg feed / kg egg mass)

1.3 Antioxidants maintain energy content of the diet

Corn Distiller’s Dried Grains with Solubles (DDGS), a by-product of corn distillation processes, are used as an alternative to corn. In DDGS, the starch content is removed, but fat is concentrated, reaching about three times the fat level of corn. This is the reason why the energy content in DDGS and corn is similar. This makes DDGS an attractive ingredient for monogastric diets; however, fat,  especially at hot temperatures in the summer, can be oxidized. The resulting rancidity and the accompanying destruction of vitamins, pigments, and amino acid leads to a decrease in the diet’s bioavailability and energy content and to poor feed conversion.

The use of antioxidants can stabilize DDGS and other fatty ingredients in the feed, maintaining nutrient integrity and availability. Figure 3 shows the performance benefits of using antioxidant product Santoquin in pork finisher diets in the USA containing 30% of DDGS.

Figure 3: Performance results for pigs receiving Santoquin (trial with Midwest pork producer)

In  poultry production, the use of DDGS is not as common as in swine. Antioxidants, however, can still help to protect the nutrients, maintain the energy content and improving FCR. The results from an extensive 2015 field study for broilers fed a diet without DDGS (shown in Figure 4) showed a net ROI of 6.7 to 1.

Figure 4: FCR in broilers receiving Santoquin, compared to non-supplemented control group

1.4 Organic acids improve intestinal processes

Organic acids, or acidifiers, can improve the gut microbiome, feed utilization, and gut health in production animals. The gut microbiome balance is aided by lowering the population of pathogenic bacteria susceptible to low pH, such as E. coli, Salmonella, and Clostridium.

Organic acids also directly attack pathogens by entering bacterial cells and changing the internal pH. Commensal bacteria such as Lactobacilli and Bifidobacteria survive as they can tolerate lower pH conditions. As pathogens constitute nutrient competitors, eliminating them improves gut health, which, is the most important precondition for optimal nutrient utilization.

The acidifying effect of organic acids furthermore favors digestion and nutrient utilization: for example, for weaned piglets that not able to produce enough HCl in the stomach, a low stomach pH is important for the activation of the proteolytic enzyme pepsin. Besides a non-optimal use of nutrients, undigested protein arriving in the intestine leads to the proliferation of undesired pathogens, decreasing health and performance.

Organic acids, therefore, improve FCR directly, by promoting nutrient utilization through the stimulation of enzymes, and indirectly, by enhancing gut health.

2. Improving feed quality

Feed quality is not only a question of raw material quality. Feed additives play an important role in ensuring feed safety and enabling optimal utilization by the animal.

2.1 Mold inhibitors preserve the feed’s value

Molds reduce the nutrient and energy content of the feed (table 1) and have a negative impact on animals’ growth performance (table 2). Active water is the crucial point for mold growth. Compared to bacteria, which need about 0.90 – 0.97 Aw (active water), most molds require only 0.86 Aw.

Mold inhibitors contain different ingredients. Surfactants bind the free water, so that the moisture of the feed persists, but the active water important for molds is reduced. Organic acids, as already mentioned before, have antifungal properties. Together, they reduce molds and prevent the degradation of energy in the feed.

Table 1: Nutrient loss in corn infested with molds

Table 2: Comparison of 28-day-old chicks performance fed not-infested and molded corn

2.2 Mitigating the negative impact of mycotoxins

Mycotoxins contamination of grains can occur in the field, during raw material harvesting, transportation, storage, handling, and even during feed processing and storage. By mitigating the negative effects of mycotoxins – such as gut and liver inflammation, kidney degeneration or reproductive disorders – the animals’ health and performance can be maintained. In today’s contamination scenarios, it is absolutely necessary to use products that adsorb mycotoxins and contain their harmful impact on animals.

The effectivity of such products in animals is crucial. Table 3 shows an optimal experimental design and Figure 5 shows the results of its application: a total recovery of the performance pays off.

Table 3: Trial design, impact of Mastersorb Gold on broilers challenged with zearalenone and DON-contaminated feed

Figure 5: Average FCR for broilers, with or without zearalenone and DON challenge, with or without Mastersorb Gold supplementation

2.3  Surfactants for microbiological control and high pellet quality in the feed mill

Moisture is important. Too dry feed results in poor palatability and digestibility, and lower pellet quality. Also moisture loss has a direct impact on production and profitability.

The use of surfactants, makes it possible to bind the moisture to the feed, reaching a larger contact surface between water and feed particles, and improving starch gelatinization and pelleting efficiency. The improvement in starch gelatinization leads to a higher pellet quality, a lower proportion of fines and a higher content of metabolizable energy.

Moreover, moist steam has a better antimicrobial effect than dry steam, leading to lower fungal and bacterial growth and preventing the production of toxins. The pelleting temperature can also be lower, protecting the nutrients.

Figure 6 shows how the use of SURF•ACE, a synergistic blend of organic acids and surfactants, improves pellet durability, moisture content, and mold occurrence for beef and poultry pellet feed.

Figure 6: Improvements in pellet durability, moisture content and mold through using SURF•ACE

3.   Using feed alternatives in ruminants – partial replacement of protein feed by urea

Ruminal bacteria are able to synthesize amino acids and, subsequently, generate a high-quality protein out of acid amides, a group of non-proteins occurring during the synthesis and degradation of proteins. What they require to do this is enough energy, minerals, and trace elements available in the feed (Weiß et al., 2011). When the bacteria arrive in the abomasum and in the small intestine they, or rather their proteins, are degraded by enzymes together with the undegradable rumen protein into useful amino acids.

With the aid of ruminal microbes, ruminants therefore partly cover their protein requirement through non-protein nitrogen. The most well-known is urea. It is critical that the urea given to animals has a degradation rate similar to other energy sources the animal consumes. Otherwise, there will be an imbalance between the quantity of usable nitrogen and the energy required for microbial protein synthesis: The urea accumulates in the rumen, becoming toxic for the microbiota and creating metabolic disorders.

Special coating technology allows for nitrogen to be released at a rate close to that of protein degradation of the main vegetable protein sources (e.g., soybean meal). This leads to a more constant nitrogen supply for the microorganisms and results in maximal synthesis of microbial protein.

4.   Save costs in the production process

Besides high pellet quality, feed millers seek to maximize production efficiency. Factors contributing to this target are the amount of fines to be reprocessed, the utilization of steam, the pellet throughput and the energy demand. Once more, the moisture of the feed is of decisive importance. Substances can be added to the feed to achieve an optimal moisture content. These substances bind free water by generating an emulsion of dietary fat and the added water.

Besides the positive effects on pellet durability, moisture content and mold growth shown above, this leads to a better general lubrication of the machinery: The addition of feed mill processing aid SURF•ACE leads to a 10-15 % lower energy demand or a higher production output without increasing energy consumption (Figure 7), depending on the mill’s requirements. Good machinery lubrication additionally reduces wear and tear, another important dimension of production efficiency

Figure 7: Improvements in pellet output and energy efficiency through using SURF•ACE

Producers can rise to the challenge of rising feed prices

Rising feed costs pose a significant challenge to everyone in animal production. We are all compelled to look for alternatives to optimize the utilization of resources. This firstly involves a critical look at the efficiency of every step in our operations, but also includes utilizing targeted feed additives. Various measures are available for animal producers to optimize feed conversion, improve feed quality, and resort to alternative ingredients. In feed production, tools are on hand to optimize the manufacturing processes, improve feed quality, and make a positive impact on animal performance. Feed price fluctuations will continue to challenge our industry. Still, while tackling short- and medium-term difficulties, we can also strategically build resilience – and take the measures today that will contribute to our long-term ambitions for sustainable and profitable production.

References

Jones, G. “Leistungsstarke Tiere und Verbraucherschutz stehen nicht im Widerspruch – Wirkung eines phytogenen Zusatzstoffs / High-performing livestock and consumer protection are not contradictory – Impact of a phytogenic additive.” Kraftfutter/ Feed Magazine 12 (2001): 468-473.

Mendel, M., Chłopecka, M., Dziekan, N., & Karlik, W. (2017). Phytogenic feed additives as potential gut contractility modifiers—A review. Animal Feed Science and Technology, 230, 30–46. https://doi.org/10.1016/j.anifeedsci.2017.05.008.

Weiß, J.W., S. Granz, W. Pabst. Tierproduktion. Thieme Verlag (2005):155-159.

Zhai, Hengxiao, Hong Liu, Shikui Wang, Jinlong Wu, and Anna-Maria Kluenter. “Potential of Essential Oils for Poultry and Pigs.” Animal Nutrition 4, no. 2 (June 2018): 179–86. https://doi.org/10.1016/j.aninu.2018.01.005.

Vitamin E prices have spiked amid production issues and lack of availability. How can you mitigate the increased cost of vitamin E inclusion?

Vitamin E prices often see severe fluctuations caused by raw materials shortages, production or distribution issues, or regulations on some key production ingredients (such as m-cresol anti-dumping rules in China leading to a global price spike some months ago).

SANTOQUIN acts as a preservative for Vitamin E, allowing more of this vitamin to enter the tissue where it exerts its antioxidant effect. In addition, in the presence of selenium, another important cellular antioxidant mineral, SANTOQUIN can help protect or spare the Vitamin E needed for proper cell function.

The Food and Agriculture Organization of the United Nations, FAO, clearly confirms this mode of action: “Dietary deficiencies of vitamins A and E seem to be ameliorated in certain circumstances and ethoxyquin promotes higher levels of vitamin A storage in the liver. Repletion/deletion experiments show that in both monogastric and ruminant animals, a diet containing an anti-oxidant protects fat soluble vitamins throughout ingestion and metabolism. The important benefit of antioxidants most probably lies in their conservation of essential nutrients and their improved utilization by the animal. Altogether too often, it is the practice to use levels of vitamin E far above the animals’ nutrient requirement and the result is economically unfavorable. It has been shown in diets designed for chicken and turkey breeders that ethoxyquin has a vitamin E sparing effect.”

Why moisture management requires both surfactants and organic acids

Moisture management starts with monitoring certain indicators. The moisture content measures the total amount of water contained in a substance, usually expressed as a percentage of the total weight. Feed manufacturers track the moisture contents of raw materials, mash feed, and pellets during all processing stages  to optimize quality, yields, and profitability.

For the purpose of preventing mold growth, however, another indicator is even more critical: water activity (a_w) is technically defined as the ratio of partial vapor pressure of water in a substance to the partial vapor pressure of pure water under the same temperature and pressure conditions. What this captures is the energy state of water in a substance, i.e. its potential for (bio)chemical activity, including the growth of bacteria, yeasts, and molds. Simply put, microorganisms will usually not grow below a certain water activity level, and the higher the water activity, the higher the chance of microbial growth (Roos, 2003).

Minimum water activity (a_w) for growth and toxin production of toxigenic fungi affecting grains

Adapted from Magan, Aldred, and Sanchis (2004)

Can we condition feed with pure water?

Why does this matter? The intense friction during grinding and mixing results in heat; subsequently, moisture from the mash feed is lost in the form of vapor. These losses need to be mitigated, when the feed is too dry, the milling equipment cannot function optimally and the pellet quality deteriorates. However, simply adding water does not work well: Pure water does not readily bind to the feed; it effectively “sits on top” of the feed surface, increases the feed’s water activity and thus becomes a perfect substrate for microbial growth. Plus, pure water steam largely evaporates again when the feed is cooled.

Surfactants

Hence, at the conditioning phase, it is critical to add surfactants to the hydrating solution. Surfactants change the way water behaves: by reducing the surface tension of water, they enable the feed particles to absorb the water and ensure that it is evenly distributed throughout the feed. There are numerous beneficial effects as improved moisture retention

• facilitates the starch gelatinization during conditioning (important for pellet digestibility and durability),
• minimizes feed shrinkage at the cooling stage,
• reduces friction and hence the energy required for the pellet die (improving milling efficiency), and
• curbs microbial growth by reducing water activity.

While surfactants contribute to mold control, feed manufacturers also require the help of organic acids to optimize the moisture content in feed while reliably preventing mold (re)contamination hazards along the distribution chain.

Organic acids

Let us consider how the most effective one, propionic acid, works: In its non-dissociated state, propionic acid has all its hydrogen ions attached to the molecule. Once it enters a mold cell, the propionic acid dissociates, meaning the hydrogen ions separate from the molecule. They reduce the intracellular pH in the mold cell and inhibit its metabolic pathways, ultimately leading to cell death (Smith et al., 1983).

Common feed ingredients such as soybean meal, maize, wheat, barley, and dehulled oats are often stored for several months. Given variable and likely challenging temperature, oxygen, and moisture conditions, their water activity levels can easily escalate (Mannaa and  Kim, 2017) – rendering the long-lasting anti-fungal activity of targeted organic acid preconditioning even more important.

SURF•ACE: Improve mill performance and pellet quality

A synergistic blend of organic acids and surfactants can achieve the objective of adding moisture without risking either the subsequent loss of moisture during cooling or the development of mold. This is the working principle behind SURF•ACE^TM feed mill processing aid, carefully formulated to best achieve the dual objective of higher feed quality and higher production efficiency. This objective is achieved in concordance with optimal resource use and lower energy requirements, thus also contributing to the feed industry’s environmental commitments.

Improved press yield

The effect of adding SURF•ACE to diets with increasing levels of fat were evaluated at more than 40 feed mills, with production capacities ranging from 5 to 20 tons per hour, under identical electricity consumption conditions. The results show that the addition of SURF•ACE to the preconditioning solution increases press throughout (t/h), relative to pure water preconditioning, by between 9 and 23 %, depending on how much preconditioning solution is applied and the level of fat in the diet:

Addition of SURF•ACE increases press throughput

*Including large volumes of hydrating solution in high-fat diets might adversely affect the durability values of the feed

What is the role of fat in this scenario? Dietary fat acts as a lubricant between the feed and the pellet die, reducing the pressure within the die. The higher the percentage of fat included in the mixer, the lower the energy required to process the mash (Pope, Brake, und Fahrenholz, 2018). The surfactants contained in SURF•ACE have an emulsifying effect; they help bind water to the fat element of the feed. The emulsion of water and fat “behaves” like fat, improving the lubrication of press and generating a higher throughput for the same electricity consumption.

Higher pellet quality

Importantly, adding SURF•ACE does not negatively affect pellet durability, a common issue in high-fat diets (Moritz et al., 2003). On the contrary, it enhances pellet durability as more crystal starch becomes gelatinized. This translates into improved results for Holmen pellet durability testing:

Addition of SURF•ACE improves pellet durability

Pellets need to withstand significant pneumatic handling, for example, during bagging and transport, and in the feed lines. The Holmen durability tester simulates this handling, and calculates the percentage of fine generated, expressed as a pellet durability index (PDI). Across six different poultry compound feed types, SURF•ACE improves pellet quality and thus the PDI. Fewer fines equate to less reprocessing for feed manufacturers and higher palatability for animals.

The next level in compound feed production

Achieving optimal moisture levels in compound feed is a complex balancing act involving technical constraints, raw material variability, microbial challenges, and the price pressures of competitive feed markets. Feed mills generally operate within a particular comfort zone, a throughput and quality level at which they minimize production problems. Thanks to its dual surfactant and preservative effects, SURF•ACE feed mill processing aid expands the comfort zone in two dimensions: From an economic point of view, the improved lubrication gives mills the choice of either pushing their performance levels closer to their equipment’s potential capacity or achieving the same results at lower electricity use. From a feed quality angle, effective mold prevention and improved pellet quality allow for safer, more palatable feed – and from there we come full circle, to safe, nutritious food for all of us.

References

Magan, Naresh, David Aldred, and Vicente Sanchis. “The Role of Spoilage Fungi in Seed Deterioration.” Essay. In Fungal Biotechnology in Agricultural, Food, and Environmental Applications, edited by Dilip K. Arora, 311–23. New York: Marcel Dekker, 2004.

Mannaa, Mohamed, and Ki Deok Kim. “Influence of Temperature and Water Activity on Deleterious Fungi and Mycotoxin Production during Grain Storage.” Mycobiology 45, no. 4 (2017): 240–54. https://doi.org/10.5941/myco.2017.45.4.240.

Moritz, J. S., K. J. Wilson, K. R. Cramer, R. S. Beyer, L. J. McKinney, W. B. Cavalcanti, and X. Mo. “Effect of Formulation Density, Moisture, and Surfactant on Feed Manufacturing, Pellet Quality, and Broiler Performance.” Journal of Applied Poultry Research 11, no. 2 (2002): 155–63. https://doi.org/10.1093/japr/11.2.155.

Moritz, J. S., K. R. Cramer, K. J. Wilson, and R. S. Beyer. “Feed Manufacture and Feeding of Rations with Graded Levels of Added Moisture Formulated to Different Energy Densities.” Journal of Applied Poultry Research 12, no. 3 (October 1, 2003): 371–81. https://doi.org/10.1093/japr/12.3.371.

Pope, J. T., J. Brake, and A. C. Fahrenholz. “Post-Pellet Liquid Application Fat Disproportionately Coats Fines and Affects Mixed-Sex Broiler Live Performance from 16 to 42 d of Age.” Journal of Applied Poultry Research 27, no. 1 (March 1, 2018): 124–31. https://doi.org/10.3382/japr/pfx054.

Roos, Y. H. “WATER ACTIVITY | Effect on Food Stability.” Essay. In Encyclopedia of Food Sciences and Nutrition Second Edition, edited by Luiz Trugo and Paul M. Finglas, 6094–6101. Cambridge, MA: Academic Press, 2003.

Smith, Philip A., Talmadge S. Nelson, Linda K. Kirby, Zelpha B. Johnson, and Joseph N. Beasley. “Influence of Temperature, Moisture, and Propionic Acid on Mold Growth and Toxin Production on Corn.” Poultry Science 62, no. 3 (1983): 419–23. https://doi.org/10.3382/ps.0620419.

How to achieve feed hygiene

Feed hygiene requires the control of microorganisms throughout the feed production chain. However, producers or retailers can rarely certify or verify feedstuffs’ safety due to the wide range of potential microbial contamination agents and hazards encountered in different feed environments (den Hartog, 2003). The relationship between feed and microorganisms varies, depending on the conditions: feed can transport pathogenic microorganisms and thus directly transmit disease; likewise, microorganisms can also be responsible for feed spoilage and thereby indirectly cause issues (Baer, Miller, and Dilger, 2013).

Since its foundation, the World Organization for Animal Health (OIE) has established standards, guidelines, and recommendations for toxin risk management, including for microorganisms that are transmissible via feed. Recurring outbreaks of Salmonella, Escherichia coli, and other familiar Enterobacteriaceae are a key concern for animal health professionals and the feed industry (Elsayed et al., 2021). However, as factors ranging from climate change to genetic mutations come into play, feed producers are working with moving targets; some of the most significant issues they might face tomorrow are unknown today. There are no easy solutions to these multifactorial problems – but in any case, corrective measures need to include quality control and quality assurance for assessing and managing the pathogenic and microbial risk situation.

To improve animal productivity sustainably, producers regularly experiment with modifying production techniques, innovating feed formulations, but also exploring new ingredients. The inclusion of new ingredients such as animal proteins, oils, and fermented products, among others, heightens the need for strict feed quality monitoring (Truelock et al., 2020). New ingredients come with causative agents of feedborne illnesses, some of which might be unknown (Goodarzi Boroojeni et al., 2016). Therefore, feed and animal producers need to consider how feed changes impact feed safety and include these hazards in their planning and risk assessments.

Better feed hygiene is crucial

For any animal production, feed processing constitutes the most crucial part of feed hygiene management, as it covers all treatments of the feed before ingestion. It is referred to as “hydrothermal processing” due to the use of heat that is required to kill most of the pathogens in raw materials, feedstuffs, and compound feed (Jones, 2011). However, whether or not hydrothermal processing will effectively eliminate a given pathogen depends on its heat resistance. Moreover, factors such as the type of feed components involved and water activity levels also need to be considered to reduce microbial pressure (Doyle and Mazzotta, 2000).

The new generation of feed milling equipment – besides elevating feed costs – can also improve feed quality (Truelock et al., 2020). These technologies tend to enhance feed stability and hygiene by modifying the physicochemical properties of the ingredients. This improves the absorption of nutrients, thereby enabling a higher feed intake efficiency with positive results for animal performance (Abdollahi, Svihus, and Ravindran, 2013). However, while increasing processing time at a given temperature can lead to a better decontamination process, it can also negatively affect some nutrients’ dynamics. This includes enzymes, proteins, minerals, vitamins, fiber and starch, and especially non-starch polysaccharides (Goodarzi Boroojeni et al., 2014).

Organic acids as a solution of feed hygiene risk management

Hence, while significant progress in feed science and feed production technology has already been made, researchers and the industry are still searching for alternative approaches to supporting feed hygiene (Goodarzi Boroojeni et al., 2016). Organic acids are a central research field as they offer promising antimicrobial properties. In combination with feed mill techniques, they already play an essential role in feed preservation (Brul et al., 2002). Despite their efficacy in inhibiting microbial growth, weak organic acids are safe to handle (especially when they are buffered) compared to inorganic acids.

In addition to their preservative effect in feed, it has been shown that organic acids can support gut health. They are not just antimicrobial agents but also acidifiers that display their impact in the stomachs of monogastric animals (Tugnoli et al., 2020).

A combined solution for microbial contamination challenges

To support the feed industry and animal production in light of feed safety challenges in AGP-free production, EW Nutrition focuses research efforts on maximizing the beneficial effect of organic acids. The ACIDOMIX range of products supports the stabilization of the gastrointestinal microflora, inhibiting pathogenic bacterial growth in feed and water. Acidomix is an efficient acidifier specially formulated to have strong antimicrobial effects applicable in feed hygiene programs. Various powder and liquid solutions offer a wide range of benefits:

• Strong antimicrobial effect, supporting the prevention of bacterial infections
• Reducing the incidence of dysbiosis
• Acidifying the feed and digestive tract
• Supporting the improvement of production performance
• Preventing feed re-contamination
• Flexible application

Feedstuffs and compound feed are at risk of contamination and re-contamination throughout the feed production chain: processing, transportation, delivery, storage, and on-farm. Thus, a holistic and integrated approach that includes optimized feed mill processing and customized organic acids is required to improve the feed’s hygiene status. The positive effects are clear: feed producers benefit economically, animal producers reap the effects of improved animal health and performance, and people get to enjoy producing and consuming safe and nutritious food.

References

Abdollahi, M R, B Svihus, and V Ravindran. 2013. “Pelleting of Broiler Diets: An Overview with Emphasis on Pellet Quality and Nutritional Value.” Animal Feed Science and Technology 179 (1–4): 1–23. https://doi.org/10.1016/j.anifeedsci.2012.10.011.

Baer, Arica A, Michael J Miller, and Anna C Dilger. 2013. “Pathogens of Interest to the Pork Industry: A Review of Research on Interventions to Assure Food Safety.” Comprehensive Reviews in Food Science and Food Safety 12 (2): 183–217. https://doi.org/10.1111/1541-4337.12001.

Brul, Stanley, Peter Coote, Suus Oomes, Femke Mensonides, Klaas Hellingwerf, and Frans Klis. 2002. “Physiological Actions of Preservative Agents: Prospective of Use of Modern Microbiological Techniques in Assessing Microbial Behaviour in Food Preservation.” International Journal of Food Microbiology 79 (1–2): 55–64. https://doi.org/10.1016/s0168-1605(02)00179-4.

Doyle, M Ellin, and Alejandro S Mazzotta. 2000. “Review of Studies on the Thermal Resistance of Salmonellae.” Journal of Food Protection 63 (6): 779–95. https://doi.org/10.4315/0362-028x-63.6.779.

Elsayed, Mohamed Sabry Abd Elraheam, Awad A Shehata, Ahmed Mohamed Ammar, Tamer S Allam, and Reda Tarabees. 2021. “The Beneficial Effects of a Multistrain Potential Probiotic, Formic, and Lactic Acids with Different Vaccination Regimens on Broiler Chickens Challenged with Multidrug-Resistant Escherichia Coli and Salmonella.” Saudi Journal of Biological Sciences. https://doi.org/10.1016/j.sjbs.2021.02.017.

Goodarzi Boroojeni, Farshad, Birger Svihus, Heinrich Graf von Reichenbach, and Jürgen Zentek. 2016. “The Effects of Hydrothermal Processing on Feed Hygiene, Nutrient Availability, Intestinal Microbiota and Morphology in Poultry—A Review.” Animal Feed Science and Technology 220: 187–215. https://doi.org/10.1016/j.anifeedsci.2016.07.010.

Den Hartog, Johan den. 2003. “Feed for Food: HACCP in the Animal Feed Industry.” Food Control 14 (2): 95–99. https://doi.org/10.1016/S0956-7135(02)00111-1.

Jones, Frank T. 2011. “A Review of Practical Salmonella Control Measures in Animal Feed.” Journal of Applied Poultry Research 20 (1): 102–13. https://doi.org/10.3382/japr.2010-00281.

Truelock, Courtney N, Mike D Tokach, Charles R Stark, and Chad B Paulk. 2020. “Pelleting and Starch Characteristics of Diets Containing Different Corn Varieties.” Translational Animal Science 4 (4): txaa189. https://doi.org/10.1093/tas/txaa189.

Tugnoli, Benedetta, Giulia Giovagnoni, Andrea Piva, and Ester Grilli. 2020. “From Acidifiers to Intestinal Health Enhancers: How Organic Acids Can Improve Growth Efficiency of Pigs.” Animals 10 (1): 134. https://doi.org/10.3390/ani10010134.

Goodarzi Boroojeni, F., W. Vahjen, A. Mader, F. Knorr, I. Ruhnke, I. Röhe, A. Hafeez, C. Villodre, K. Männer, and J. Zentek. “The Effects of Different Thermal Treatments and Organic Acid Levels in Feed on Microbial Composition and Activity in Gastrointestinal Tract of Broilers.” Poultry Science 93, no. 6 (June 1, 2014): 1440–52. https://doi.org/10.3382/ps.2013-03763.

How lipopolysaccharides cause disease

LPS are rather large and structured chemical molecules with a weight of over 100,000 D. They are highly thermostable; boiling in water at 100°C for 30 minutes does not destabilize their structure. LPS consist of three chemically distinct sections: a) the innermost part, lipid A, consisting mostly of fatty acids; b) the core, which contains an oligosaccharide; and c) the outer section, a chain of polysaccharides called O-antigen (Figure 1).

Figure 1: Structure of an LPS

The toxicity of LPS is mainly caused by lipid A; however, both lipid A and O-antigen stimulate the immune system. This happens when the LPS pass the mucosa and enter the bloodstream or when they attack the leukocytes.

The intestinal mucosa is the physical immune barrier that protects the microvilli from external agents (bacteria, free LPS viruses, etc.). Despite its strength (the thickness, for example, amounts to ≈830 µm in the colon and ≈123 µm in the jejunum), vulnerable points exist (cf. Zachary 2017).

LPS can easily come into contact with the cells of the lamina propria (a layer of connective tissue underneath the epithelium) through the microfold (M) cells of the Peyer’s patches (which consist of gut-associated lymphoid tissue). The M cells are not covered by mucus and thus exposed.

Secondly, LPS can also pass through the mucosa, where they become entangled in this gelatinous structure. There, they come into contact with the lymphocytes or can reach the regional lymph nodes through the afferent lymphatic vessels.

Thirdly, LPS might affect the tight junctions, the multiprotein complexes that keep the enterocytes (cells that form the intestinal villi) cohesive. By destabilizing the protein structures and triggering enzymatic reactions that chemically degrade them, LPS can break the tight junctions, reaching the first capillaries and, consequently, the bloodstream.

The presence of endotoxins in the blood, endotoxemia, can trigger problematic immune responses in animals. An innate immune stimulation leads to an increase in the concentration of pro-inflammatory cytokines in the blood and, consequently, to an induced febrile response in the animal: heat production increases, while the available metabolic energy decreases.  As a result, performance suffers, and in the worst-case scenario, septic shock sets in. Furthermore, when LPS compromise intestinal integrity, the risk of secondary infections increases, and production performance may decline.

LPS’ modes of action

How does all of this happen? The physiological consequences of endotoxemia are quite complex. Simplified, the immune system response to LPS in the blood takes three forms:

• The stimulation of TLR4 (toll-like receptor 4) induces monocytes and macrophages to secrete critical pro-inflammatory cytokines, primarily interleukin (IL) IL-1β, IL-6, IL-8, and tumor necrotic factor (TNF) α and β. TLR4 is a structure on the cell membrane of mainly macrophages and leukocytes, which is activated by the LPS-binding protein (LBP).
• The complement cascade constitutes about 10% of plasma proteins and determines the chemotaxis and activation of leukocytes. It can form a membrane attack complex (MAC), which perforates the membranes of pathogenic cells, enabling lysis.
• The Hagemann factor, also known as coagulation factor XII: once stimulated by LPS, it initiates the formation of fibrin (through the intrinsic coagulation pathway), which might lead to thrombosis. The Hagemann factor directly stimulates the transformation of prekallikrein to kallikrein (enzymes involved in regulating blood pressure).

Figure 2: How LPS leads to endotoxemia – 3 modes of action

These three modes of action of inflammatory stimulation lead to important physiological reactions:

• Pro-inflammatory cytokines (see above) modulate the functional expression of other immune cell types during the inflammatory response;
• Metabolites of arachidonic acid (prostaglandins, leukotrienes, and lipoxins), intra- and extracellular messengers that influence the coagulation cascade;
• Synthesis in the blood of bradykinin, a peptide responsible for the typical symptoms of inflammation, such as swelling, redness, heat and pain;
• PAF (platelet-activating factor), which creates inflammatory effects through narrowing of the blood vessels and constriction of the airways, but also through the degranulation of leukocytes.

The symptoms of endotoxemia are:  hypotension, metabolic acidosis, hemoconcentration, intestinal hemorrhage, fever, activations of neutrophils and endothelial cells, and predisposition to thrombosis.

In case of a progression to septic shock, the following sequence takes place:

1) Reduction in blood pressure and increased heart rate (hemodynamic alterations)

2) Abnormalities in body temperature

3) Progressive hypoperfusion at the level of the microvascular system

4) Hypoxic damage to susceptible cells

Up to here, symptoms follow a (severe) endotoxemia pathogenesis. A septic shock furthermore entails:

5) Quantitative changes in blood levels of leukocytes and platelets

6) Disseminated intravascular coagulation (see Hageman factor)

7) Multi-organ failure

8) Death of animal

If an animal is continously challenged with endotoxins, experiences septic shock, or comes close to it, it risks developing LPS tolerance, also known as CARS (compensatory anti-inflammatory response syndrome). This syndrome essentially depresses the immune system to control its activity. The anti-inflammatory prerogative of CARS is not to interfere directly with the elimination of pathogens but to regulate the “excessive” inflammatory reaction in a hemostatic way. However, this regulation can be extremely dangerous as the syndrome involves a lack of homeostasis control, and an excessive depression of the immune system leaves the organism exposed to the actual pathogens.

Farm animal research on endotoxemia pathogenesis

Lipopolysaccharides are difficult to quantify in the intestine of a live animal. One way to evaluate a possible endotoxemia is to analyze biomarkers present in the bloodstream. The most important one is the LPS themselves, which can be detected in a blood sample taken from the animal via ELISA. Other biomarkers include pro-inflammatory interleukins, such as TNF α and β, IL-6 or IL-8, and fibrin and fibrinogen (though they are not specific to endotoxemia). It is vital to carry out a blood sample analysis to deduce a possible endotoxemia from symptoms and performance losses in the animal.

How the metabolic effects of endotoxemia depress performance

One of the biggest issues caused by endotoxemia is that animals reduce their feed intake and show a poor feed conversion rate (FCR). Why does this happen? The productive performance of farm animals (producing milk, eggs, or meat) requires energy. An animal also requires a certain baseline amount of energy for maintenance, that is, for all activities related to its survival. As a result of inflammation and all those physiological reactions mentioned above, endotoxemia leads to a feverish state. Maintenance needs to continue; hence, the energy required for producing heat will be diverted from the energy usually spent on producing milk, egg, meat, etc., and performance suffers.

The inflammation response can result in mitochondrial injury to the intestinal cells, which alter the cellular energy metabolism. This is reflected in changes to the levels in adenosine triphosphate (ATP), the energy “currency” of living cells. A study by Li et al. (2015) observed a respective reduction of 15% and 55% in the ATP levels of the jejunum and ileum of LPS-challenged broilers, compared to the unchallenged control group. This illustrates the extent to which animals lose energy while they experience (more or less severe) endotoxemia.

Figure 3: Reduction in ATP level in Jejunum and Ileum in broilers (adapted from Li et al., 2015)

A piglet study by Huntley, Nyachoti, and Patience (2017) took this idea further (Figure 4):  3 groups of 10 Yorkshire x Landrace pigs, weighing between 11 and 25 kg, were studied in metabolic cages and in respiratory chambers. This methodology allows for simultaneous measurement of oxygen consumption, CO₂ production, energy expenditure, physical activity, and feed/water intake. The study found that LPS-challenged pigs retained 15% less of the available metabolizable energy and showed 25% less nutrient deposition. These results show concrete metabolic consequences caused by the febrile response to endotoxemia we discussed above.

Figure 4: Retained Energy as % of ME intake and nutrient deposition of pigs in metabolic cages (adapted from Huntley, Nyachoti, and Patience, 2017)

Control treatment (CON) = Pigs fed by a basal diet
Immune system stimulation treatment (ISS) = Pigs given LPS (E. coli serotype 055:B5) injection

A loss of energy retained due to a reduction in available metabolizable energy leads to losses in performance as the amount of energy available for muscle production and fat storage will be lower. Furthermore, the decrease in feed intake creates a further energy deficit concerning production needs.

A trial carried out at the University of Illinois examined the effects of repeated injections of 400 μg E. coli LPS on chick performance from 11 to 22 days after hatching. The chicks were fed casein-based diets with graded levels of arginine. LPS administration reduced weight gain (P<0.05) and feed intake, and these effects tended to be worse at higher levels of arginine supplementation (Figure 5). The researchers hypothesize that, in response to endotoxin and elevated cytokine levels, macrophages use more arginine to produce nitric oxide, diverting it from protein production for muscle development.

Figure 5: Effects of LPS on feed intake and body weight gain in chicks fed graded level of arginine (based on Webel, Johnson, and Baker, 1998)

NC = negative control

This data on poultry complements the results for swine, again showing that endotoxin-induced energy losses quantifiably depress animal performance even in milder disease cases.

The way forward: Endotoxin mitigation

Animals suffering from endotoxemia are subject to severe metabolic dysfunctions. If they do not perish from septic shock, they are still likely to show performance losses. Moreover, they at great risk of immunosuppression caused by the immune system “overdrive.” Effective endotoxin mitigating agents can help to prevent these scenarios.

EW Nutrition’s Mastersorb Gold is not only a leading anti-mycotoxin agent; thanks to its specific components, it effectively binds bacterial toxins. An in vitro study conducted at the Hogeschool Utrecht laboratory (part of Utrecht University) evaluated the binding capacity of Mastersorb Gold on LPS compared to three different competitor products. All products were tested at two different inclusion rates. At an inclusion rate of 0.25%, only Mastersorb Gold reduced the toxin load on the solution by 37%. At 1% inclusion, Mastersorb Gold bound 75% of the toxin, while only one competitor product demonstrated any binding (10%).

Lipopolysaccharides are a constant challenge for animal production. The quantity of Gram-negative bacteria in an animal intestine is considerable; therefore, the danger of immune system over-stimulation through endotoxins cannot be taken lightly. Producers need to prioritize the maintenance of intestinal eubiosis in production animals proactively; for instance, through targeted gut health-enhancing additives based on phytomolecules and, possibly, organic acids.

Most importantly, the detrimental impact of LPS can be mitigated by using a high-performance agent such as Mastersorb Gold. To limit losses from an energy point of view yields positive results in terms of production levels and the prevention of secondary infections, preserving animal health and farms’ economic viability.

By Claudio Campanelli, EW Nutrition

References

Adib-Conquy, Minou, and Jean-Marc Cavaillon. “Compensatory Anti-Inflammatory Response Syndrome.” Thrombosis and Haemostasis 101, no. 01 (2009): 36–47. https://doi.org/10.1160/th08-07-0421.

Huntley, Nichole F., C. Martin Nyachoti, and John F. Patience. “Immune System Stimulation Increases Nursery Pig Maintenance Energy Requirements.” Iowa State University Animal Industry Report 14, no. 1 (2017). https://doi.org/10.31274/ans_air-180814-344.

Li, Jiaolong, Yongqing Hou, Dan Yi, Jun Zhang, Lei Wang, Hongyi Qiu, Binying Ding, and Joshua Gong. “Effects of Tributyrin on Intestinal Energy Status, Antioxidative Capacity and Immune Response to Lipopolysaccharide Challenge in Broilers.” Asian-Australasian Journal of Animal Sciences 28, no. 12 (2015): 1784–93. https://doi.org/10.5713/ajas.15.0286.

Mani, Venkatesh, James H Hollis, and Nicholas K Gabler. “Dietary Oil Composition Differentially Modulates Intestinal Endotoxin Transport and Postprandial Endotoxemia.” Nutrition & Metabolism 10, no. 1 (2013): 6. https://doi.org/10.1186/1743-7075-10-6.

Webel, D.M., R.W. Johnson, and D.H. Baker. “Lipopolysaccharide-Induced Reductions in Body Weight Gain and Feed Intake Do Not Reduce the Efficiency of Arginine Utilization for Whole-Body Protein Accretion in the Chick.” Poultry Science 77, no. 12 (1998): 1893–98. https://doi.org/10.1093/ps/77.12.1893.

Zachary, James F. “Chapter 4 – Mechanisms of Microbial Infections.” Essay. In Pathologic Basis of Veterinary Disease, 132–241. St Louis, MO: Mosby, 2017. https://doi.org/10.1016/B978-0-323-35775-3.00004-7.