Hatchery management in ABR production

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By T.J. Gaydos

Producing high-quality chicks is critical to the success of any broiler program, but it is even more important in an antibiotic-free (ABF) program. The hatchery is the perfect environment for the incubation of eggs and, consequently, bacteria and mold. This makes hatchery sanitation a very high priority in ABF production systems because of the inability to use antibiotics in the hatchery or later in production.

Chick quality can be divided into two categories:

  • microbiologic
  • chick vitality

The reality is many of the processes that impact these two categories are often intertwined but can be generally separated into

  • sanitation practices
  • setting/hatching practices

It is not helpful to set specific objective benchmarks for an individual hatchery without understanding its specific challenges. The hatchery manager must realize that the end product is a healthy, robust chick; therefore, benchmarks and numerical goals for the individual hatchery, breed, and flock age need to be established.

There are a host of measurements that can be performed and data that can be collected; however, it only makes sense to collect only information that will be used to make decisions. It is easy to over-collect and under-utilize data.

Hatchery sanitation

Bacterial contamination

Hatchery sanitation starts at the breeder farm. Eggs are a significant source of contamination in the hatchery; consequently, floor eggs should not be brought to the hatchery. If they must be hatched for egg flow needs, it is essential to at least segregate them from the regular egg flow throughout the process. It is imperative to send a clean egg pack to the hatchery (transport and store the eggs at proper temperatures and humidity). Once the eggs are at the hatchery, the focus is on proper storage, incubation, and hatching. 

Monitoring sanitation

The risk of multiplying bacteria in the hatchery is high. Hatchery equipment can be difficult to clean, there are sufficient nutrients to support microbial growth, and the environment is perfect for incubation. Developing a program to monitor the cleanliness of the hatchery is a critical step in managing sanitation. The whole hatchery must be regularly cleaned and disinfected, and the most effort should be spent on chick contact surfaces.

Egg flats must be clean and dry before returning to the breeder farm. Hatcher baskets must be clean and dry before eggs are transferred. The tray wash machine should use a detergent and disinfectant to remove and sanitize the trays (the water temperature should be 140oF). A disinfectant with residual efficacy should be used after the tray wash. Too low of a temperature will encourage bacterial growth, and too high a temperature can damage the baskets.

When using an in ovo vaccination system, it is essential to clean and disinfect the machine after every use and prepare it for the next transfer. Chick belts, counters, chick baskets, hatchers, and setters are all areas that can harbor pathogens. Wet areas are also at risk for harboring disease: wet bulb thermometers, humidification equipment, and tray washers. All these areas should be regularly checked for cleanliness by traditional microbiology or rapid ATP testing.

It is important to monitor the hatchery air quality on a regular basis to ensure the level of bacteria and fungi is not too high. This is most effectively accomplished by placing air plates in key locations for air movement such as clean hatchers and setters and their respective halls, and plenums. The areas where vaccines are stored, mixed, and prepared should be surgical suite clean. 

Hatching practices

Chick vitality

A high-quality, active chick is one of the keys to program success. The actual profile used to hatch that bird is a mixture of breeder flock profile, hatchery equipment, climate, and experience. When evaluating a hatchery and a hatching program, it is best to start at the endpoint and work backward.

Managing chick comfort in the holding room is vital to set the chicks up for success on the farm. The chicks will tell you if they are too hot or too cold and if they have too much or too little airflow. This is determined by experience and monitoring behavior.

Tracking chick rectal temperatures is a useful way to check comfort. Remember that a small animal can change their body temperature from ideal to hyper- or hypothermic extremely quickly. On average, 103.5oF is a good benchmark for chick internal temperature. Moving backward through the process, evaluate the vaccine spray cabinet to ensure chicks are getting the proper vaccines at the proper rate.

The next critical opportunity to monitor chick vitality is when chicks are being separated from hatch debris. The volume of chicks passing through the site allows for rapid evaluation of the flock. In this area, it is important to check for open navels, strings, red hocks, green chicks, dirty chicks, and general appearance and behavior.

Hatch debris

The egg should be pipped and broken almost exactly in half. The debris should have minimal meconium, yolk stains, and should not smell bad. Excess meconium is an indication that the hatch window is prolonged, and the chicks spent too much time in the machine before pull.

When eggshells are crushed in one’s hand they should break, but the membrane should remain intact. If the membrane also breaks, it is a sign that the chicks were potentially overheated, incubated too long, or humidity was too low. 

Chick yield

One of the most useful measures of the setting process is chick yield, which is the weight of the chick at hatch compared to the weight of the egg set. Chicks with a low yield were set with a high temperature or low humidity or were hatched for a long time before being removed from the hatcher. Chicks with a high chick yield are a result of the opposite: low temperature and high humidity incubation or did not spend enough time in the hatcher post-hatch. The ideal chick yield depends on the breed of chicken and the individual hatchery, but 67-68 % yield is a good benchmark.

Breakout

Analyzing hatch debris is a crucial tool for understanding setting and hatching efficiencies. Embryo mortality is variable but tends to follow a consistent pattern. The majority of embryo mortality is early (1-7 days), with little mortality in the middle (8-14 days), and the second increase in embryo mortality occurring from 15-18 days. Results should be recorded, and a standard developed for the hatchery. Deviations from this standard should be investigated.

When aiming to improve the data collection process, focus on building a program that prioritizes the most useful information. Breakouts and chick yields are two of the most meaningful tests to modify the hatching process. Sanitation checks and monitoring of disinfectant levels at critical sanitation steps are valuable to improve hatchery quality. When all the pieces come together, high quality egg pack, sanitation, and excellent hatchery management, the result is a high-quality chick ready to succeed on the farm.




Broiler breeder management in ABF production: 3 essential steps

CHICKEN Kueken Gruppe Mix WEB

By T.J. Gaydos

Broiler breeders are the basis for the egg supply of an integrated company. All the management details of raising broiler breeders are important and require attention. Raising breeders and managing for persistency of lay, peak, fertility, and egg handling are important for all production systems. These details become more important when managing their progeny without the use of antibiotics.

Management in an ABF system requires extra attention – especially egg handling and sanitation. With the inability to use antibiotics in the progeny, it is critical to not bring additional pathogens into the hatchery on or in dirty eggs. A clean, well-managed egg pack will improve performance and animal welfare and significantly reduce seven-day mortality and the risk of foodborne illness.

1.      Cleanliness in the broiler breeder house and egg room

Managing egg cleanliness starts in the broiler breeder house before the first egg is laid. The house needs to be cleaned between flocks; at a minimum, water lines and nest pads should be cleaned and sanitized. The egg handling equipment and egg room should also be cleaned and disinfected. Special attention should be paid to egg contact surfaces and places where water accumulates, such as refrigeration and humidification equipment. If the previous flock had any disease issues, the houses should be thoroughly cleaned and disinfected. Between flocks, pest control is critical to reduce disease pressure: flies, rodents, and darkling beetles should be the focus as they are well-documented transmitters of disease. When adding shavings back to the house, it is important to not overfill the house to ensure there is a step between the scratch and the nest and thus help reduce the amount of litter and feces tracked into the nests.

 

2.      Training the birds

Once new breeders are moved to the house, it is important to train the birds on their location and not let hens learn to sleep in the nests. As hens begin to lay, training them not to lay floor eggs is an essential part of a clean egg pack.

Ensuring there are no dark spots, that any floor eggs are picked up quickly, and the scratch is walked on a regular basis are all important parts of the training to lay in nests. The temptation to set floor eggs is high, especially visibly clean eggs; the best way to eliminate this temptation is to reduce the amount of floor eggs. Visibly clean floor or slat eggs typically contain several logs more bacteria than clean nest eggs. Intestinal health is important to decrease the likelihood of soiled eggs.

High quality feed ingredients should always be used in breeder diets and the electrolyte balance carefully monitored to reduce the risk of flushing.

3.      Handling the eggs

The egg is well evolved to prevent contamination of the chick. There are multiple layers of protection: cuticle, shell, outer and inner shell membranes, and albumen. The cuticle and shell must be protected to reduce contamination. When removing minimal visible contamination, it is important to damage as little of the cuticle as possible.

3.1 Removing dirt

Dry contamination should be scraped off with a fingernail or soft plastic scraper. Wet contamination should be removed with a clean paper towel or disinfectant wipe. When removing wet contamination every effort should be made to prevent cross contamination of a larger area of the egg. Eggs should not be buffed clean since this may push dust and bacteria into the pores of the egg, limiting gas exchange and increasing contamination risk.

Any significantly soiled egg should be discarded. It is not advised to wash eggs or wet eggs for disinfection.

Gentle handling of eggs is important to reduce the risk of micro-cracks in the shell, further increasing the risk of bacterial contamination and dehydration.

3.2 Egg temperature and humidity

When packing eggs, fill the buggies from the bottom to the top. This decreases the risk of heating already cooled eggs, potentially reducing embryo viability. If egg packing equipment is used, it is important to clean the machine regularly. Special focus should be paid on the suction cups and rollers since they are in direct contact with the eggs and are very hard to clean.

As eggs cool, a slight vacuum is produced that may draw any liquid on the surface into the egg. Every effort should be made to ensure that eggs do not get wet. If they become wet, it is imperative to allow them to dry before putting them in the cooler. Egg trays and racks should be thoroughly cleaned and disinfected at the hatchery before returning them to the farm. Dirty or wet trays should not be used, they should either be thoroughly cleaned and disinfected on the farm or returned to the hatchery for cleaning.

Managing cooler temperatures is vital for hatchability. Additionally, it is important that eggs are continuously getting cooler to reduce the risk of sweating eggs. The hatchery egg cooler should be 15ºC or 59ºF, the farm egg cooler 2ºC warmer or 17ºC, and the egg transport truck in the middle (~16ºC). The humidity during storage should be 70-80% RH. Humidification devices are a high risk for microbial contamination; therefore, ensure that they are cleaned and disinfected frequently, and any mist is not directed towards the egg pack.

Conclusion

Appropriate management of the egg supply is key for any poultry company. The need for increased cleaning and disinfection is amplified in an ABF system. Clean and properly handled eggs are a fundamental step to producing high quality chicks.




How animal nutrition can contribute to sustainability

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By Dr. Inge Heinzl, Editor, EW Nutrition

 

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.

SWINE PIGS PIGLETS SUSTAINABLE AMR
Animal nutrition solutions can support producers’ sustainability contributions, from animal welfare to antibiotic reduction

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 POULTRY FEEDFeed 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/.




ABF poultry production: How to keep coccidiosis in check

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By T.J. Gaydos

Coccidiosis control consists of programs, including ionophores, chemical coccidiostats, vaccines, and gut health-promoting natural products. Sometimes, these are combined (Noack, Chapman, and Selzer, 2019). Antibiotic-free (ABF) production requires new approaches – this article will look at how different solutions can be successfully implemented.

Meticulous coccidiosis management in ABF productions is crucial to safeguard animal welfare and performance.

What makes up a successful coccidiosis control program for ABF systems?

When managing a poultry program without antibiotics in the U.S., where ionophores are classified as antibiotics, the only available tools for coccidiosis control are vaccines, chemical coccidiostats, and natural products supporting gut health during challenging times.

  • The use of a chemical-only program is possible and often successful. Still, the choice of chemicals is limited, and the risk of building resistance must always be considered and managed through the appropriate rotation of active ingredients.
  • A second option is a coccidiosis vaccine with or without chemical coccidiostats. This is an excellent long-term option but the most difficult to manage.
  • A third effective option is a coccidiosis vaccine combined with the use of phytomolecule-based solutions contributing to the coccidiosis control program and delivering improved gut health.

What do most ABF newcomers do?

When making the transition from conventional to ABF production, broiler producers usually try:

  1. A chemical coccidiostat program,
  2. A bio-shuttle program: a coccidiosis vaccine, followed by a chemical coccidiostat, or
  3. Phytomolecule-based feed additives; typically, in combination with a coccidiosis vaccine or chemical program.

When the operation can master managing the coccidiosis vaccine and other husbandry challenges, the optimal solution is the combination of vaccination and phytomolecule-based feed supplements.

Why a combination?

A coccidiosis control program based on vaccination begins in the hatchery and continues through live production. Its success relies on many moving parts working in sync to produce the desired result of early uniform immunity to coccidiosis. Phytomolecule-based products additionally can support the animals in terms of gut health, oxidative balance, and immunity.

Vaccination success depends on attention to detail

If one decides to use vaccination for coccidiosis control, the following points must be considered to achieve high effectiveness.

Vaccine storage – the right temperature is crucial

Proper storage is essential for all vaccines. In general, coccidiosis vaccines should be stored between 2° to 7°C (35° to 45°F), but optimally, one asks the vaccine manufacturer for product-specific directions. Coccidiosis vaccines must not freeze. Freezing will severely damage or kill the oocysts, thus significantly reducing efficacy. It is also important to ensure that there are no cold spots in the refrigerator. Hence, vaccines should be stored in the middle of a shelf with air space around or in a foam-insulated place inside the fridge.

For monitoring the temperature, an analog high/low thermometer should be placed by the vaccine. The temperature should be recorded, and the thermometer reset daily. To minimize the risk of administering a frozen vaccine, it is recommended to put freeze indicators outside the boxes. If, despite all these measures, vaccines are suspected to have frozen, segregate the suspect product and contact the supplier for assistance.

Vaccine administration – mind an even distribution for all steps

The goal of vaccination is to build early and uniform immunity in all chickens, which is achieved by exposure to repeated cycles of coccidia replication in the intestine.

1.      Even distribution of the oocysts in the vaccine

It is essential to ensure that all oocysts flow from the bottle into the distribution jug when mixing the vaccine. The oocysts should be well-mixed and then must be constantly agitated to remain suspended in solution. The most common way to suspend oocysts is to use a small air pump to bubble the vaccine, creating turbulence.

2.      Even spraying of the vaccine onto the chicks

The next important step is to ensure that the chicks are evenly covered with the vaccine. When in doubt, run a chick box through the spray cabinet, collect the nozzles’ output, and measure the volume sprayed. To check the spray pattern, set a piece of clear hard plastic on top of the pegs in the chick basket and run the box through the spray cabinet. Evaluate the spray pattern on the plastic sheet and adjust as needed to ensure an even spraying. The spray pattern should be checked every time a new batch of vaccines is mixed.

Even spraying of coccidiosis vaccine can be easily tested using a clear plastic sheet.

3.      A similar amount of vaccine intake for all chicks

Coccidiosis vaccines must be preened and consumed to be effective. Adding a dye to the spray compatible with the vaccine will help stimulate the birds to preen. A well-lit and temperature-controlled processing and holding area will promote preening behavior. Tongues should be checked regularly to ensure that chicks consume the vaccine. At a minimum, check ten birds per basket and ten baskets per lot. More than 98% of birds should have evidence of vaccine consumption within 10-15 minutes post-vaccination.

Chick vitality is a critical success factor in an ABF program. Healthy chicks perform better in the field. In the context of a coccidiosis vaccine, they are more apt to preen, more likely to consume food and water quickly, and less likely to excessively pick at the litter.

A dye helps to evaluate if the coccidiosis vaccine was evenly sprayed across all chicks.

Uniform immunity through effective farm management

A successful coccidiosis vaccination program achieves uniform immunity against coccidia, which slowly develops from the hatchery. For this purpose, birds must be evenly spread throughout all stages of growth to seed the litter evenly with oocysts and to have even coccidiosis pressure in all parts of the house.

Time management allows even immunization

Birds should be turned out from half to full house between 9 and 11 days. This schedule allows the birds to excrete the first round of oocysts and for the oocysts to sporulate and be consumed by the birds.

The birds need to be moved to full house before they secrete the second round of oocysts. This will allow the oocysts to be spread uniformly in the house. Coccidia reproduce exponentially and the second round of oocyst production is significantly more numerous than the first.

It is possible to brood birds in the full house while on coccidiosis vaccine. Still, it is complicated to manage the coccidiosis cycling because bird density is generally too low to ensure that birds effectively cycle the vaccine strain oocysts.

Litter consistency is decisive

Litter management is essential to control the cycling of coccidiosis because one stage of the life cycle of coccidia occurs in the litter. Litter moisture of 25% is ideal. When litter is squeezed in a fist, it should briefly form and immediately break apart. If it stays formed, it is too wet. If the litter is free-flowing and dusty, it is too dry for adequate sporulation.

Non-antibiotic supplements support coccidiosis management

Managing coccidiosis cycling requires attention to detail and is probably the most challenging part of adequately managing an ABF program. All farms are not equal and need to be supervised according to their specific needs. The use of non-antibiotic feed and water additives can help control coccidiosis and other enteric diseases.

Some non-antibiotic supplements have anticoccidial (e.g. amprolium, saponins, tannins) or antibacterial (e.g., plant extracts) activity. When used correctly, these may improve the performance of birds in a vaccination or chemical-based coccidiosis control program. Other non-antibiotic alternatives such as probiotics, prebiotics, organic acids, and yeast cell wall extracts have been shown to improve gastrointestinal health. The combination of excellent animal husbandry and the correct feed/water additive program is the key to success.

References

Noack, Sandra, H. David Chapman, and Paul M. Selzer. “Anticoccidial Drugs of the Livestock Industry.” Parasitology Research 118, no. 7 (2019): 2009–26. https://doi.org/10.1007/s00436-019-06343-5.




Want to reduce antibiotic use? Biosecurity and sanitation are crucial

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By T.J. Gaydos

Biosecurity may not sound like an exciting topic at first, but it is a critical component of responsible poultry production. It is not enough to devise a strong biosecurity program; that program must also be followed by all people that interact within the system. It only takes one dirty boot or tire to ruin months of hard work.

Achieving good results with a flock largely depends on protecting the birds from biosecurity risks

Antibiotic reduction in poultry requires biosecurity

In a poultry operation, feed, people, and equipment constantly need to go in and out of farms and mills. Thus, no biosecurity program can be perfect. The intensity of the program needs to balance the realities of farming and the current disease pressure. The best program takes all of those into account, additionally considers local weather, availability of supplies, and company/farm staff. It is simple enough to be done even when no one is watching and should be easily scalable in case of increased disease pressure.

The rigorousness of a program must be in due proportion to the local circumstances. Having a biosecurity program that is too strict for the perceived disease pressure may result in people taking the path of least resistance. They probably will not follow instructions, especially if there is not enough monitoring and training to reinforce the value of biosecurity. On the other hand, a program with too lax guidelines will not have the desired effect.

The discrepancy between care requirements and separation

Unfortunately, the most valuable animals in an operation are often the most frequently visited by the most people. Pullets need closely monitored feedings, vaccines, and deworming. Breeders need eggs collected and shipped. Hatcheries require a labor force and maintenance. The feed mill and hatchery are central and overlapping points for all areas of the operation. The human and vehicle traffic at these locations must be closely monitored to reduce the risk of rapid disease transmission.

Feed mills are critical sites for biosecurity measures in poultry production

A physical barrier or sign indicating a biosecurity area on a farm or building entrance can help remind people of the program. Of course, these signs will not stop a disease from entering, nor a person determined to enter a site, but they will cause well-trained people to pause and reflect if they are making a sound decision.

Hygiene is a critical factor

It is well documented that hands and feet are significant transmitters of human and animal pathogens. Several studies have shown that hand washing can reduce absenteeism in school-aged children by 29-57%, thanks to a decrease in gastrointestinal diseases (Wang et al., 2017). Hand washing also reduces the incidence of respiratory illness in human populations by up to 21% (Aiello et al., 2008). Mycoplasmas can survive for one day in a person’s nose, for up to three days in hair, and up to 3-5 days on cotton or feathers (Christensen et al., 1994). Influenza viruses endure 1-2 days on hard surfaces (Bean et al., 1982) and more than a month in pond water (Domanska-Blicharz et al., 2010).

When building a biosecurity program, it is essential to consider the relevant pathogens of concern and the practical ways to reduce their risk of transmission.

How to establish an effective biosecurity program

Generally, biosecurity comprises two important parts:

  • Physical biosecurity, being the combination of all the physical barriers such as boot washes, signs, and disinfection
  • Operational biosecurity, covering the processes that protect an operation. This includes downtime, visiting birds in age order, time out for birds from people visiting sick flocks, and respect for physical biosecurity measures. Operational biosecurity starts with training, not only regarding the tasks required to be secure, but also the importance of disease prevention.

Establish several zones

When designing a program, consider four zones of increasing cleanliness: off-farm, on-farm, transition zone, and the animal housing area (Figure 1). Each zone should have a control point to reduce the pathogen load coming in, with exact measures depending on current disease status and bird value. These measures include vehicle sanitation and movement restrictions, footwear cleaning and disinfection, and use of personal protective equipment (PPE).

Figure 1: the four “cleanliness zones” in a farm

Increasing cleanliness from off-farm (red) to on-farm (orange) separated by a physical barrier. The entrance to the facility (transition zone; yellow) and the animal housing area (green).

Cleaning and disinfection are two of the core measures

As hands and feet are the main transmitters of pathogens, washing and sanitizing them is a priority. The outside of the house must be left outside, meaning that hands should be washed frequently and shoes sanitized between sites. Shoe covers should be put on when entering the house.

Cleanliness of the cell phone is often overlooked as a source of disease transmission (Olsen et al., 2020). It is a powerful tool: camera, notebook, light… and notoriously hard to clean. Cleaning and disinfection also apply to all shared tools and equipment that enter farms.

Prevent undesired “cohabitants”

Another critical point in biosecurity is the control of undesired pests and farm animals. Baits must be rotated, available where rodents are frequent, appropriately spaced, and secured from non-target animals. Habitats for pests need to be removed, the perimeter of the buildings must be clear of vegetation and debris, feed and grain spills picked up, and equipment stored away from the facilities. Pets and other farm animals should be kept away from the perimeter of the house and should under no circumstance be allowed to enter the facilities.

Tailored biosecurity programs keep your flock healthy

It is impossible to design a blanket biosecurity program for every operation. Understanding microbiology and disease transmission along with the risk points in a production system will allow a comprehensive plan to be developed. It is important to consider biosecurity as an investment in health and not an optional expense. No program is perfect, but small changes can significantly reduce the risk of pathogens entering the system and leading to major economic and animal welfare issues.

References

Aiello, Allison E., Rebecca M. Coulborn, Vanessa Perez, and Elaine L. Larson. “Effect of Hand Hygiene on Infectious Disease Risk in the Community Setting: A Meta-Analysis.” American Journal of Public Health 98, no. 8 (2008): 1372–81. https://doi.org/10.2105/ajph.2007.124610

Bean, B., B. M. Moore, B. Sterner, L. R. Peterson, D. N. Gerding, and H. H. Balfour. “Survival of Influenza Viruses on Environmental Surfaces.” Journal of Infectious Diseases 146, no. 1 (1982): 47–51. https://doi.org/10.1093/infdis/146.1.47.

Christensen, N. H., Christine A. Yavari, A. J. McBain, and Janet M. Bradbury. “Investigations into the Survival of MYCOPLASMA GALLISEPTICUM, Mycoplasma Synoviae And Mycoplasma Iowae on Materials Found in the Poultry House Environment.” Avian Pathology 23, no. 1 (1994): 127–43. https://doi.org/10.1080/03079459408418980.

Domanska-Blicharz, Katarzyna, Zenon Minta, Krzysztof Smietanka, Sylvie Marché, and Thierry van den Berg. “H5n1 High Pathogenicity Avian Influenza Virus Survival in Different Types of Water.” Avian Diseases 54, no. s1 (2010): 734–37. https://doi.org/10.1637/8786-040109-resnote.1.

Olsen, Matthew, Mariana Campos, Anna Lohning, Peter Jones, John Legget, Alexandra Bannach-Brown, Simon McKirdy, Rashed Alghafri, and Lotti Tajouri. “Mobile Phones Represent a Pathway for Microbial Transmission: A Scoping Review.” Travel Medicine and Infectious Disease 35 (2020): 101704. https://doi.org/10.1016/j.tmaid.2020.101704.

Wang, Zhangqi, Maria Lapinski, Elizabeth Quilliam, Lee-Ann Jaykus, and Angela Fraser. “The Effect of Hand-Hygiene Interventions on Infectious Disease-Associated Absenteeism in Elementary Schools: A Systematic Literature Review.” American Journal of Infection Control, 2017. https://doi.org/10.1016/j.ajic.2017.01.018.




Antibiotics: Keep this effective weapon sharp

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By Technical Team, EW Nutrition

Antibiotics are a precious resource whose long-term efficacy must be protected – for human and animal health. This is a difficult challenge for healthcare providers (veterinarians and medical doctors), as well as farmers and integrators. In this series of articles, we will explore the general and specific measures and solutions through which animal production can contribute to the overall reduction of antibiotic use.

Responsible animal production contributes to maintaining antibiotic efficacy

Shortly after the discovery of penicillin in 1929, Alexander Fleming already pointed out the possibility of resistance during an interview with the New York Times. The first case of penicillin resistance was reported only one year after clinical trials began; within 20 years, 80% of Staphylococcus aureus isolates were resistant to penicillin (Lobanovska and Pilla, 2017).

Over the years, clients and patients have gotten used to receiving a pill to quickly fix their ailments. Often, antibiotics have been prescribed for illnesses they were not effective against, including viral challenges. This has unnecessarily accelerated the rate of resistance development. To reverse this trend, education is key. At the same time, the judicious use of antibiotics, meaning the correct antibiotic for the challenge plus proper administration and duration of use, is paramount for all medical professionals to help preserve the efficacy of these critical substances.

Antibiotic use in animal production must be reduced

For many years, animal producers have used antibiotics as growth promoters. The E.U. banned this type of use in 2006, and the United States followed in 2017. Evaluations have shown a decrease in antibiotic use in the U.S.: In 2014, according to the FDA, 17,000 tons of antibiotics were sold in the United States for livestock, representing 80 percent of all U.S. antibiotics sales. In 2019, a total of about 11,000 tons of antibiotics were sold for use in food-producing animals (FDA, 2020).

As the number of isolated multi-drug resistant bacteria increases and the discovery and approval of new antibiotics slows, it is imperative that the use of antibiotics in animal production, especially those that are critically important for humans, is reduced to a minimum. Hence, antibiotics should only be used to treat, control, or prevent diseases in case of imminent risk, but not for growth-promoting purposes.

Scanning electron micrograph of methicillin-resistant Staphylococcus aureus bacteria (yellow) and a dead human white blood cell (red). Credit: National Institute of Allergy and Infectious Diseases/NIH

Customers’ requests for antibiotic-free chicken push antibiotic reduction

Many birds are already raised without antibiotics in the US and elsewhere because of the demands of the market. Since 2016, chicken antibiotic sales decreased by 62% (Dall, 2020). Frequently, the goal of these antibiotic-free (ABF) production programs is to differentiate products in a highly competitive commodity market. The reduction of antibiotic use has been a secondary, generally unintended consequence.

Nevertheless, to meet customer demands for ABF products, antibiotics that are not important to human health but for production (e.g., ionophores) have also been eliminated. In many cases, this has negatively affected growth performance and bird health. As the requirements for production efficiency and welfare standards increase, transitioning from “conventional” to ABF production poses a challenge for everyone involved.

Antibiotic reduction through improved management

One must never trade animal welfare for reduced antibiotics use, but the need for them can be decreased through improved management practices. Flock health starts with genetics companies selecting birds that are resilient to disease and management challenges and continues all the way to the processing plant. All of the inputs and practices must be optimized in modern poultry production to maintain a high level of performance and animal welfare while reducing reliance on antibiotics.

Antibiotic-free requires diligent management

When antibiotics are not available, attention to detail becomes more decisive. All aspects of production are important, but the most critical stages are those that affect the downstream process. The pullets, breeders, and hatchery require the most meticulous care. Additionally, all production factors must meet the highest quality standards: feed, light, air quality, water quality, litter quality, biosecurity, vaccination, sanitation, nutrition and feeding.

Antibiotic reduction requires meticulous attention to detail to safeguard animal welfare.

Non-antibiotic feed additives support ABF programs

ABF production is all about sustainability. For agricultural operations to survive and thrive in the future, one has to move away from the old paradigm of “saving the way to success”. This is not impossible in ABF production, but misses out on the larger picture of long-term profitability, investment in innovation, and system change.

Non-antibiotic feed and water additives are essential resources to support sustainable management. To mention a few, probiotics, prebiotics, toxin binders, organic acids, and phy­tomolecules are all options for reducing the need for antibiotics based on different modes of action. Phytomolecules, for example, often have antimicrobial properties, some toxin binders can bind bacterial toxins, and pre- and probiotics support the gut flora. There are many kinds of solutions on the market; the key is to find the right ones for your issues.

Antibiotic stewardship: together for a healthier future

There is already a large body of literature demonstrating the benefits of alternative or complementary solutions. More importantly, there are already many people that successfully raise birds and other animals without antibiotics. Whenever possible, leverage your professional network and talk to trusted people with unique experiences. Working together, we can build a healthier future for people and animals.

 

The Antibiotic Reduction series

The series that debuts here consists of a set of articles offering professionals a practical overview of poultry production with reduced antibiotic use. The independent expert in charge, starting with the next article in the series, is Dr. TJ Gaydos, who holds a Master’s degree in Avian Medicine and is a diplomate of the American College of Poultry Veterinarians.

Dr. Gaydos works with integrated poultry companies and allied industries, focusing on bird health and antibiotic-free production performance. He has spent his veterinary career working to improve intestinal health, animal welfare, production efficiency, and reduce zoonotic diseases. He works extensively with intestinal health, probiotics and prebiotics, and other non-antimicrobial feed additives.

Topics covered under Dr. Gaydos’s guidance include biosecurity, nutrition, pullet management, hatchery sanitation, gut health, and more. Together they provide an extensive look at the producers’ pain points and potential strategies to maintain bird health while mitigating the need for antibiotics.

References

AccessScience Editors, “U.S. Bans Antibiotics Use for Enhancing Growth in Livestock.” Access Science. McGraw-Hill Education, January 1, 1970. https://www.accessscience.com/content/u-s-bans-antibiotics-use-for-enhancing-growth-in-livestock/BR0125171.

Dall, Chris. “FDA Reports Another Rise in Antibiotic Sales for Livestock.” FDA Reports Another Rise in Antibiotic Sales for Livestock | International Biosecurity and Prevention Forum, December 16, 2020. https://www.ibpforum.org/news/fda-reports-another-rise-antibiotic-sales-livestock.

Lobanovska, Mariya, and Giulia Pilla . “Penicillin’s Discovery and Antibiotic Resistance: Lessons for the Future?” Yale Journal of Biology and Medicine. 90, no. 1 (March 29, 2017): 135–45.

U.S. Food and Drug Administration. “2020 Summary Report On Antimicrobials Sold or Distributed for Use in Food-Producing Animals” Food and Drug Administration, 2019. https://www.fda.gov/media/144427/download.




Stop feed spoilage: How organic acids can preserve feed quality

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By Technical Team, EW Nutrition

Feed spoilage is a significant issue for the feed industry, leading to loss of nutrients, feed waste, and substantial economic issues for feed and animal producers worldwide (Leyva Salas et al., 2017). Fungal growth is one of the main causes of feed spoilage; it can occur at any stage of the feed production chain, including grain pre- and post-harvest processes, during feed production or storage. Organic acids and their salts are globally used in animal nutrition for microbial preservation and supporting animal health.

Organic acids help preserve animal feed and prevent spoilage through molds, yeasts, and mycotoxinsOrganic acids help preserve animal feed and prevent spoilage through molds, yeasts, and mycotoxins

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 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.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 indicatorsFigure 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.




Antioxidant benefits in pig feed

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By Technical Team, EW Nutrition

In modern swine production, one of the key aspects for success is a balanced diet. This essentially means ensuring that the animal meets its daily nutritional requirements for maintenance, growth, and reproduction. In order to provide an appropriate diet and safe feed for the animals, the sensory and nutritional characteristics of the feed must be preserved and issues like the oxidation of the feed must be avoided.

This article aims to highlight why oxidation in  feed can become a big concern for swine producers, what the problems resulting from oxidation in pig feed are, and present practical solutions to improve feed quality and pig performance by controlling the oxidation.

Feed oxidation: What are the dangers?

In pig diets, various sources of lipids are added to increase caloric density, provide essential fatty acids, improve feed palatability, improve pellet quality, and reduce dust (Keer et al., 2015). Some of the feed ingredients are more susceptible to oxidation because of their physical and chemical characteristics, such as milled grains and ingredients of animal origin and vegetable oils with a high content of polyunsaturated fatty acids.

Oxidative rancidity is a type of lipid deterioration. In the oxidation process, the free radicals react with lipids and proteins and induce cellular and tissue damage.

Some consequences of oxidative deterioration are the destruction of fat-soluble vitamins, supplemental fats, and oils. Preserving these ingredients is crucial because fats and oils provide a high quantity of energy and essential fatty acids. At the same time, vitamins, such as those present in vitamin premixes, are indispensable for optimal animal growth and performance.

The oxidation process also results in by-products with strong unpleasant taste and odor, and even toxic metabolites. In addition, oxidized feed has less protein, amino acids, and energy content. All these factors are relevant when resources, in the current scenario of high prices of feed ingredients and inputs, might be wasted due to poor feed management.

Performance losses caused by oxidation

Lipid oxidation can incur several losses regarding the pigs’ performance. Feeding oxidized lipids significantly decreases growth rate, feed intake and efficiency, immune function, and weight gain efficiency in pigs, especially in breeding animals, since the exposure occurs over long periods.

The ingestion of products resulting from the oxidative deterioration of fatty acids leads to irritability of the intestinal mucosa, diarrhea, and, in extreme cases, can result in liver degeneration and cell death. DeRouchey et al. (2004) observed reduced growth rates in pigs that are fed rancid white grease. Ringseis et al. (2007) reported that feeding oxidized sunflower oil increased oxidative stress markers in the small intestine of pigs, while Boler et al. (2012) reported that feeding pigs oxidized corn oil reduced growth performance (Table 1). Lu et al. (2014a) reported signs of liver damage in pigs subjected to dietary oxidative stress, increasing plasma bilirubin content, and enlarged liver size.

Table 1. Effects of dietary corn oil quality and antioxidant inclusion on barrow performance (Source: Boler et al., 2012)

There are some theories as to why oxidized feed causes such effects. According to Dibner et al. (1996), vitamins and polyunsaturated fatty acids deteriorate in the absence of antioxidants, and oxidized fats and their byproducts can negatively affect cells, resulting in changes in membrane permeability, viscosity, secretory activity, and membrane-bound enzyme activity. These primary effects lead to observable systemic effects. In order to prevent these damaging consequences, antioxidants have become a widely used alternative.

The power of antioxidants

Chemical antioxidants (Table 2) are added to animal feeds to delay fat and vitamin oxidation, which keeps the diet palatable and helps prolong the feed’s shelf life, ultimately maintaining the quality of the ingredients (Jacela et al., 2010). They prevent the binding of oxygen to free radicals. Dietary antioxidants have also been used in several species of animals to replace vitamin E, which is known for its antioxidant powers. Antioxidants are highly applicable in warm climates, when high levels of fat are added to the diet, and in areas where byproducts high in unsaturated fats are commonly used.

Table 2. Commonly used chemical antioxidants

Lu et al. (2014b) studied the effects of dietary supplementation with a blend of antioxidants (ethoxyquin and propyl gallate) on carcass characteristics, meat quality, and fatty acid profile in finishing pigs fed a diet high in oxidants. They reported that the inclusion of antioxidants minimized the effects of the high oxidant diet. The treatments including antioxidants, whether combined with vitamin E or not, had positive results in carcass weight, back fat, loin characteristics, and extractable lipid percentage.

Fernandez-Duenas (2009) studied the use of antioxidants in feed containing fresh or oxidized corn oil and its effects on animal performance, the oxidative status of tissues, meat quality, shelf life, and the antioxidant activity of skeletal muscle of finishing pigs. They reported that barrows fed with diets with the antioxidant blend showed increased feed efficiency. Orengo et al. (2021) showed that feeds protected with antioxidants could compensate for low vitamin E supply with regard to growth performance in the starter phase. Hung et al., 2017 theorized that the impacts on growth performance are likely related to the lack of adequate antioxidant capacity of the diet and oxidative stress status.

As literature and application results show, the use of antioxidants in pig feed is crucial to minimize adverse effects from oxidized feed and allow the animals to express their full performance potential.

SANTOQUIN: preserving feed quality

From a practical standpoint, swine producers must consider some criteria for selecting a good antioxidant, which must preserve feed components, be nontoxic for humans and pigs, show effectiveness at very low concentrations, and be economically sustainable.

Considering those major characteristics, EW Nutrition offers a range of antioxidant solutions for the preservation of feed ingredients and feeds for poultry and swine through their SANTOQUIN product line. Santoquin is a feed preservative that protects supplemental fats, oils, meals, and vitamin premixes and protect feed from oxidation. Santoquin provides unsurpassed protection from oxidative rancidity, and it has proven effects against oxidation in feeds (Figure 1) ensuring the prolonged shelf life of feeds, especially during suboptimal storage conditions, such as those with high environmental temperature and elevated levels of moisture.

Figure 1. Antioxidant efficacy and competitiveness. SANTOQUIN MAX feed preservative is a proprietary antioxidant blend that effectively prolongs the shelf life of feed and feed ingredients by reducing oxidation rate.

Studies have been conducted to show the beneficial effects of Santoquin. Ethoxyquin, contained in Santoquin, has been used in the swine industry for over five decades and has been shown to improve growth performance and markers of oxidative status in pigs (Dibner et al., 1996). Ethoxyquin is also known for being the most efficacious and cost-effective antioxidant. Lu et al. (2014b) showed that the addition of an antioxidant blend (ethoxyquin and propyl gallate) protected pigs fed with a high-oxidant diet from oxidative stress more efficiently than vitamin E supplementation (Figure 2).

Figure 2. Concentrations of vitamins A and E across treatments in the plasma (A) and muscle (B). HO: high oxidant diet containing 5% oxidized soybean oil (peroxide value at approximately 180 mEq/kg of oil, 9 mEq/kg in the diet) and 10% of a PUFA source (providing approximately 55.57% of crude fat that contains docosahexaenoic acid [ DHA] at 36.75%, and 2.05% DHA in the diet); VE: the HO diet with 11 IU/kg of added vitamin E; AOX: the HO diet with an antioxidant blend (ethoxyquin and propyl gallate, 135 mg/kg); VE+AOX: the HO diet with both vitamin E and antioxidant blend; SC: a standard corn–soy control diet with nonoxidized oil and no PUFA source. The HO pigs were switched to the SC diet after day 82 as an intervention for poor health and performance. The samples came from two pigs from each pen. The VE treatment lost 1 replicate during the feeding phase and transportation period (n = 4), while in other treatments, n =5. (Source: Lu et al., 2014b)

Conclusion

The negative effects of oxidation in pig feed can result in diets with lower biological energy value. To avoid that, antioxidants help maintain intestinal health, ensure a safe food intake, preserve the ingredients and resources used in pig production. Overall, antioxidants help swine producers improve feed conversion and achieve more productive animals and lower mortality caused by toxicity. At the end of the day, the use of antioxidants is associated with better profitability.

 

References

Boler, D. D., Fernández-Dueñas, D. M., Kutzler, L. W., Zhao, J., Harrell, R. J., Campion, D. R., Mckeith, F. K., Killefer, J., & Dilger, A. C. (2012). Effects of oxidized corn oil and a synthetic antioxidant blend on performance, oxidative status of tissues, and fresh meat quality in finishing barrows. Journal of Animal Science, 90(13), 5159–5169. https://doi.org/10.2527/jas.2012-5266

DeRouchey, J. M., Hancock, J. D., Hines, R. H., Maloney, C. A., Lee, D. J., Cao, H., Dean, D. W., & Park, J. S. (2004). Effects of rancidity and free fatty acids in choice white grease on growth performance and nutrient digestibility in weanling pigs. Journal of Animal Science, 82(10), 2937–2944. https://doi.org/10.2527/2004.82102937x

Dibner, J. J., Atwell, C. A., Kitchell, M. L., Shermer, W. D., & Ivey, F. J. (1996). Feeding of oxidized fats to broilers and swine: Effects on enterocyte turnover, hepatocyte proliferation and the gut associated lymphoid tissue. Animal Feed Science and Technology, 62(1 SPEC. ISS.), 1–13. https://doi.org/10.1016/S0377-8401(96)01000-0

Fernández-dueñas, D. M. (2009). Impact of oxidized corn oil and synthetic antioxidant on swine performance, antioxidant status of tissues, pork quality, and shelf life evaluation.

Hung, Y. T., Hanson, A. R., Shurson, G. C., & Urriola, P. E. (2017). Peroxidized lipids reduce growth performance of poultry and swine: A meta-analysis. Animal Feed Science and Technology, 231, 47–58. https://doi.org/10.1016/j.anifeedsci.2017.06.013

Jacela, J. Y., DeRouchey, J. M., Tokach, M. D., Goodband, R. D., Nelssen, J. L., Renter, D. G., & Dritz, S. S. (2010). Feed additives for swine: Fact sheets–flavors and mold inhibitors, mycotoxin binders, and antioxidants. Journal of Swine Health and Production, 18(1), 27-32.

Kerr, B. J., Kellner, T. A., & Shurson, G. C. (2015). Characteristics of lipids and their feeding value in swine diets. Journal of Animal Science and Biotechnology, 6(1), 1-23. https://doi.org/10.1186/s40104-015-0028-x

Lu, T., Harper, A. F., Zhao, J., Estienne, M. J., & Dalloul, R. A. (2014). Supplementing antioxidants to pigs fed diets high in oxidants: I. Effects on growth performance, liver function, and oxidative status. Journal of animal science, 92(12), 5455-5463. https://doi.org/10.2527/jas.2013-7109

Lu, T., Harper, A. F., Dibner, J. J., Scheffler, J. M., Corl, B. A., Estienne, M. J., Zhao, J., & Dalloul, R. A. (2014b). Supplementing antioxidants to pigs fed diets high in oxidants: II. Effects on carcass characteristics, meat quality, and fatty acid profile. Journal of Animal Science, 92(12), 5464–5475. https://doi.org/10.2527/jas.2013-7112

Orengo, J., Hernández, F., Martínez-Miró, S., Sánchez, C. J., Peres Rubio, C., & Madrid, J. (2021). Effects of commercial antioxidants in feed on growth performance and oxidative stress status of weaned piglets. Animals, 11(2), 1–13. https://doi.org/10.3390/ani11020266

Ringseis, R., Piwek, N., & Eder, K. (2007). Oxidized fat induces oxidative stress but has no effect on NF-κB-mediated proinflammatory gene transcription in porcine intestinal epithelial cells. Inflammation Research, 56(3), 118–125. https://doi.org/10.1007/s00011-006-6122-y




Harvest to bring significant quality challenges for feed, says EW Nutrition [Press Release]

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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.

 

info@ew-nutrition.com

https://ew-nutrition.com/

+49 4445 9868-0




Norovirus outbreaks could be avoided with IgY technology

oysters

By Technical Team, EW Nutrition

In July, Public Health England (PHE), an executive agency of the Department of Health and Social Care in the United Kingdom, reported a rise of norovirus outbreaks in the country. Norovirus, a highly contagious virus similar to the coronavirus, is the main cause of viral food poisoning from shellfish. Symptoms include vomiting, diarrhea, cramps, as well as muscle aches and headaches.

The PHE press release shows an increase in outbreaks during the last two months, returning to pre-pandemic levels. According to the organization, the number of outbreaks has nearly tripled when compared to the same time period in the last 5 years, affecting people of all age groups and settings in England. Closed places where the virus can spread quickly, especially childcare facilities and nursing homes, are the most affected, as shown below.

Enteric virus outbreaks reported in England during the 2020/2021 season. Source:  National Norovirus and Rotavirus Bulletin, Public Health England, 2021 National Norovirus and Rotavirus Bulletin (publishing.service.gov.uk)

Norovirus: A global problem

The issue is not restricted to England. According to the CDC (Centers for Disease Control and Prevention), about one out of every five cases of acute gastroenteritis that leads to diarrhea and vomiting is caused by norovirus, responsible for over 200,000 deaths and a global economic burden of more than $60 billion. The large costs come from healthcare costs and productivity losses and can be seen in low, middle, and high-income countries as shown below.

Global economic burden of norovirus gastroenteritis. Source: https://doi.org/10.1371/journal.pone.0151219.t003

Prevention is key

Noroviruses is easily transmitted through contact with infected individuals or contaminated surfaces. There are many ways to reduce the spread of the virus (e.g., washing the hand thoroughly with soap and water) but prevention is key.

The outbreaks often occur from contaminated oysters or other shellfish which are consumed raw, making foodborne transmission accountable for a considerable number of cases. The conventional cleaning and purifying methods currently used in the industry cannot reliably reduce the number of norovirus contained in its digestive organ, therefore it is of extreme necessity to look new solutions to improve safety in shellfish production. And this is exactly what EW Nutrition does.

Combatting the norovirus: the IgY solution

With our mission to mitigate the impact of antimicrobial resistance in mind, we developed a new technology to improve food safety in shellfish production. Our solution is based on a high value source of natural egg immunoglobulins (IgY), which will prevent the virus from infecting the oyster’s digestive organ.

This method consists in adding anti-norovirus IgY to the seawater during the depuration process, which is a postharvest treatment where the shellfish are placed in tanks of clean seawater to reduce contaminant levels and allow shellfish to cleanse or purge themselves by continuation of their normal filter-feeding and digestive processes.

Natural, effective, and safe

While depuration is a highly effective and very common commercial practice for removing different pathogens, several studies show that the depuration process alone is not enough to remove completely or lower the norovirus to a safe level. On the other hand, various trial results show that shellfish treated with EW Nutrition technology is completely free from or has very low amount of live norovirus, allowing a safe consumption of raw oysters and minimizing the risk of any other outbreaks.

For more information about our solution, you can reach out to Lucas Queiroz or to your local EW Nutrition contact.

 

References

Bartsch et al. 2016. Global Economic Burden of Norovirus Gastroenteritis. https://doi.org/10.1371/journal.pone.0151219

 Lee, R.; Lovatelli, A.; Ababouch, L. Bivalve depuration: fundamental and practical aspects. FAO Fisheries Technical Paper. No. 511. Rome, FAO. 2008. 139p.

National Norovirus and Rotavirus Bulletin, Public Health England, 2021 National Norovirus and Rotavirus Bulletin (publishing.service.gov.uk)

Norovirus outbreaks increasing in England – GOV.UK (www.gov.uk)

Norovirus Worldwide | CDC