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.

VISBEK, 28 September – EW Nutrition announces the launch of a novel gut health solution for poultry. Pretect D, a proprietary blend of phytomolecules, helps maintain bird performance and farm profitability.

Trials indicate that Pretect D offers natural support even during Eimeria-related challenges, making it an effective addition to programs focused on gut health issues.

“EW Nutrition is a front runner when it comes to innovations driving lower use of antibiotics and harmful chemicals in the animal production industry,” says Michael Gerrits, Managing Director. “The introduction of Pretect D signifies our commitment to helping customers make livestock production more sustainable through best-in-class natural solutions.”

Research with Pretect D conducted around the globe, in research institutes and under commercial conditions, evidenced improved body weight and lower feed conversion rate. EW Nutrition is also following up on initial results indicating significant oocyst count reduction.

“Poultry producers are affected by reduced animal performance and high costs for preventive and therapeutic control,” says Madalina Diaconu, Product Manager for Pretect D. “What our product brings to the market is an ability to support the natural defenses of birds. We’re also investigating our product’s ability to impair the growth cycle of the Eimeria population.” Pretect D is developed to be used in combination with vaccines, ionophores and chemicals, as part of the shuttle or rotation program.

About EW Nutrition

For the global animal production and feed industries, EW Nutrition offers innovative, comprehensive solutions for gut health, feed quality, pigmentation, digestibility, on-farm performance and more.

Headquartered in Germany, with R&D and manufacturing facilities around the world, EW Nutrition owns the entire value chain, from development and scale-up to production, distribution, and support in 90+ markets.

Coccidiosis is one of the most devastating enteric challenge in the poultry industry costing over over 14 billion US$ per year (Blake et al., 2020). In the early days of  intensive poultry production, outbreaks of Eimeria tenella, were most destructive. Eimeria tenella is a coccidia species that causes severe haemorrhages and hypovolemic shock, leading to a fatal outcome for the affected bird. 

Poultry producers need to control the performance and welfare issues caused by subclinical coccidiosis

Understanding and managing coccidiosis in poultry

However, today, subclinical coccidiosis accounts for even more of production losses due to intestinal cells injuries: lower body weights, higher feed conversion rates, lack of flock uniformity, failures on skin pigmentation and, at the end mortality. Variation in the supply and quality of animal feed exacerbates the issue and compromises farm profitability even more. To tackle this challenge, we need to understand the basics of coccidiosis control in poultry and what options producers have to manage coccidiosis risks.

From Eimeria infection to disease

Coccidiosis is a disease caused by protozoan parasites, mainly of the genus Eimeria, that are located in the small and large intestines. Being very resistant and highly contagious, these protozoa are easily transmitted by various routes (via feed, litter, water, soil, material, insects, and wild animals).

Coccidia are present in all livestock species. However, the infection is particularly severe in poultry. The health consequences can be significant: loss of appetite, reduction in feed intake, increased FCR, enteritis, hemorrhagic diarrhea, and mortality. The most common species of Eimeria in broilers are: E. acervulina, E. mitis, E. maxima, E. brunetti, E. necatrix, E. praecox, and E. tenella. They are widely found in broiler productions across the globe (McDougall & Reid, 1991).

Figure 1: Sporulated oocyst of Eimeria maxima and E. Acervulina (40 x)

The pathogenesis of infection varies from mild to severe and is largely dependent on the magnitude of infection. Coccidiosis outbreaks are related to multiple factors that, together, promote a severe infestation in the farm.

Within poultry, the highest economic impact is in broilers, where the most common species of Eimeria are E. acervulina, E. maxima, E. tenella and E. necatrix, which all show high virulence. However, pathogenicity is influenced by host genetics, nutritional factors, concurrent diseases, age of the host and the particular species of the Eimeria (Conway & McKenzie, 2007).

Figure 2: Interaction of factors that promote coccidia outbreaks

The Eimeria infection starts with the ingestion of protozoa that are at a sporulated stage. Once inside the gut, the protozoa liberate the sporozoites. This infective form can get into enterocytes and then begin a massive reproduction, killing thousands of intestinal cells. (Olabode et al., 2020; Shivaramaiah et al., 2014)

Figure 3: Eimeria spp. life cycle

The reproduction potential depends on the coccidia species. E. acervulina, E. mitis and E. praecox have the highest reproduction rate. This characteristic is closely related to their short life cycle.

In broilers, coccidiosis usually occurs after 21 days of age. The infection spreads gradually from day 1 already, depending on species of Eimeria and their virulence. A typical progression of coccidiosis in broilers is shown in Figure 4.Figure 4: Typical development of a coccidia infection in relation to broiler feed phases

Coccidiosis control in poultry: Strategy guidelines

The intrinsic characteristics of coccidiosis makes this parasite unique and many times frustrating to control. Resistance to available coccidiostats makes this task even harder.  Good farm management, litter hygiene, and the use of control coccidiosis programs such as shuttle and rotation are functional measures to prevent clinical coccidiosis. Successful control strategies specifically recognize the importance of monitoring, use anticoccidial drugs wisely, and include vaccines where applicable.

Monitoring

The first step is to establish a strict monitoring program in all stages of production, including the feed mill. It is important to verify that therapeutics are included in the feed in an adequate form and quantity, and that the follow-up in the field takes place.

Field monitoring should be frequent and in line with the operation’s coccidiosis management program. Field monitoring is a complementary work that collates clinical, necropsy, and faeces findings to closely track the disease situation.

Coccidiosis control in poultry operations needs to include rigorous monitoring

Anticoccidial drugs

Since the middle of the 20^th century, chemotherapeutic agents have offered the best way to control coccidia. However, unbridled use of anti-coccidial drugs and the emergence of the new resistant field strains of coccidia have made it increasingly challenging to control coccidiosis with commonly available coccidiostat drugs.

The coccidiostats have been classified in two groups: ionophores, molecules obtained from microbiological fermentation, and chemicals, synthetic compounds. The mode of action of ionophores is to interfere with the membrane ion exchange, killing the extracellular stages (sporozoites and or merozoites) as they expend energy to maintain the osmotic balance. Chemical compounds can have an anticoccidial effect even on extracellular and intracellular stages (Sumano López & Gutiérrez Olvera, 2005).

However, resistance development is limiting their effectiveness, and certain compounds cannot be used in older birds or in hot environments. Moreover, government regulations often include anti-coccidial drugs in bans on antibiotics use. This does not mean that these drugs are not crucial to controlling this disease, but it is important to use alternative tools: they help make a coccidiosis control program not only less dependent on anticoccidial drugs but also more robust.

Vaccines

There are two commercial kinds of coccidia vaccines; the first one uses natural strains. These Eimeria are selected from field outbreaks, show a medium pathogenicity, and allow for a controlled replication of a coccidia infection. The second kind of vaccines include attenuated strains; these are precocious strains and birds usually show low or no post-vaccinal reactions.

The management of coccidia vaccines is the principal challenge for using this tool to control coccidia. Special vaccination training is required at the hatchery, which then needs a follow-up on the farm. In the field, this follow-up and the alignment of all the protocols has proven challenging for many producers.

Managing coccidiosis in poultry: Next steps

The limitations chemotherapy and vaccines have led to a surge in the quest for effective  natural solutions. Recent research into plant-derived phytochemicals shows that these compounds have properties that make them an interesting tool against coccidiosis (cf. Cobaxin-Cárdenas, 2018). Knowledge, research, and technological developments are now ready to offer solutions that can be an effective part of coccidia control programs. These natural solutions create opportunities to make poultry production more sustainable by reducing dependency on harmful drugs.

References

Bafundo, K.W., L. Gomez, B. Lumpkins, G.F. Mathis, J.L. McNaughton, and I. Duerr. “Concurrent Use of Saponins and Live Coccidiosis Vaccines: The Influence of a Quillaja and Yucca Combination on Anticoccidial Effects and Performance Results of Coccidia-Vaccinated Broilers.” Poultry Science 100, no. 3 (2021): 100905. https://doi.org/10.1016/j.psj.2020.12.010.

Blake, Damer P., Jolene Knox, Ben Dehaeck, Ben Huntington, Thilak Rathinam, Venu Ravipati, Simeon Ayoade, et al. “Re-Calculating the Cost of Coccidiosis in Chickens.” Veterinary Research 51, no. 1 (September 14, 2020). https://doi.org/10.1186/s13567-020-00837-2.

Cobaxin-Cárdenas, Mayra E. “Natural Compounds as an Alternative to Control Farm Diseases: Avian Coccidiosis.” Farm Animals Diseases, Recent Omic Trends and New Strategies of Treatment, March 21, 2018. https://doi.org/10.5772/intechopen.72638.

Conway, Donal P., and M. Elizabeth McKenzie. Poultry Coccidiosis: Diagnostic and Testing Procedures. Ames, IA, IA: Blackwell Publishing, 2007.

McDougall, L. R., and W. M. Reid. “Coccidiosis.” Chapter. In Diseases of Poultry, edited by B. W. Calnek, H. W. Yoder, W. M. Reid, C. W. Beard, and H. J. Barnes. Ames, IA: Iowa State University Press, 1991.

Olabode, Victoria Bose, Dashe Yakubu Gunya, Umaru Mada Alsea, Tobias Peter Pwajok Choji, and Israel Joshua Barde. 2020. “Histopathological Lesions of Coccidiosis Natural Infestation in Chickens”. Asian Journal of Research in Animal and Veterinary Sciences 5 (2), 41-45. https://www.journalajravs.com/index.php/AJRAVS/article/view/30090.

Shivaramaiah, Chaitanya, John R. Barta, Xochitl Hernandez-Velasco, Guillermo Téllez, and Billy M. Hargis. “Coccidiosis: Recent Advancements in the Immunobiology of Eimeria Species, Preventive Measures, and the Importance of Vaccination as a Control Tool against These Apicomplexan Parasites.” Veterinary Medicine: Research and Reports 2014, no. 5 (April 28, 2014): 23–34. https://doi.org/10.2147/vmrr.s57839.

Sumano López, Héctor, and Gutiérrez Olvera Lilia. Farmacología Clínica En Aves Comerciales. México: UNAM, Departamento de Fisiología y Farmacología, 2005.

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 140^oF). 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, 103.5^oF 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.

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.

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.

by Predrag Persak, Regional Technical Manager North Europe, EW Nutrition

The main sustainability challenge for broiler production lies in securing enough high-quality, nutritious, safe, and readily available food at a reasonable cost. At times, feed ingredients have to be included that are not nutritionally ideal and might compromise one’s broilers’ health and wellbeing. However, counteracting this threat with prophylactic antibiotics is not acceptable: We must minimize the use of antibiotics to mitigate antimicrobial resistance. The way forward is to go beyond static and linear nutritional value-to-price thinking. A dynamic nutritional strategy focusing on the interdependencies between ingredients, gut, microbiome, and digestion, enables sustainable ABF broiler production.

Sustainable ABF broiler production requires a dynamic, gut health-oriented nutritional strategy

Sustainability vs. ABF production – is there a trade-off?

The United Nations’ 1987 Brundtland report offers a clear definition of sustainability as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” “Ability” includes the availability of resources – and in broiler production, which is one of the most efficient livestock productions, resources have always been a top priority. As a constantly evolving industry, broiler production has been quick to adopt sustainability into its management strategies. The use of the resource that is antibiotics, however, poses particular challenges.

Humans and animals depend on antibiotics to fight microbial infections. It is essential to maintain their efficacy so that future generations can lead healthy lives. Antibiotic efficacy is under threat from the development of antimicrobial resistance, which emerges from overuse and misuse in both human and veterinary medicine. Across the globe, broilers are still raised with the assistance of antibiotics. Either for disease therapy, to prevent disease occurrence, and still, in some parts of the world, to enhance performance. Driven by regulatory and consumer demands, broiler production with minimal or no use of antibiotics is rapidly gaining importance.

The challenges of antibiotic-free broiler production

ABF systems encounter numerous challenges since production requirements change drastically. Stock density must be lower; it takes longer to reach the desired weight; and more feed is needed to produce the same amount, with a higher risk of morbidity and mortality (Cervantes, 2015). The latter can result in more birds needing treatment with medically important antimicrobial drugs. All those challenges need to be overcome by adopting suitable strategies related to nutrition, genetics, management, biosecurity, welfare, and food safety.

As animal nutritionists, our focus lies on nutrition, feed, feed materials, additives, feed processing, feeding, and their (positive or negative) influence on the sustainability of ABF broiler production. However, we cannot look at these dimensions of production as a separate process. They are linked in the whole food chain and are affected by changes that happen in other related parts. An obvious example is feed production, which has an enormous impact on the overall sustainability of ABF broiler production:

• Due to raw material shortages, diets are becoming ever more complex, containing more single feed ingredients. For some of them, we need a better understanding of their impact on ABF broiler production (e.g., sunflower, rapeseed, beans, lupins).
• The nutritional composition of raw materials changes due to limitations in fertilizer use, and variability within the same raw material group is expected to increase.
• New food waste-reducing feed materials can enhance feed security but also require nutritional profiling to integrate them into diets.
• Local feed material production in humid and warm environments can introduce various pathogens into the feed/food chain.
• Increases in known and the emergence of new antinutrients and feed components that impair animal health, performance, and feed efficiency.
• Sustainability-driven pesticide reduction raises concerns about mycotoxins contaminating feed ingredients.
• Nutrient reduction to support gut health and, primarily, lower the excretion of nitrogen and phosphorous, negatively affects growth, nutritional standards, and the ability to freely select feed materials to include in broiler diets.
• The value (of which price is also part) of raw materials will be compromised, due to availability and nutritional variability.

Mycotoxin contaminated-feed can damage production animals’ performance, health, and welfare

When striving for a sustainable ABF broiler production approach, the possibility for errors becomes higher, while the error margin becomes smaller. The solution lies in helping the animals to mitigate the impact of stressors by focusing on the interaction of ingredients, gut, microbiome, and digestion. It is a holistic approach centered on gut health. Keeping the intestines BEAUTIful will help you produce in challenging conditions without the use of antimicrobials.

Keep the broiler gut BEAUTIful and resilient to stress

The BEAUTIful formula captures the six areas producers need to target for supporting broiler gut health:

Barrier

If it’s working correctly, the effective gatekeeper knows what gets in and what stays out. When the barrier function is compromised due to stress, pathogens can cause infections, disrupt health, and negatively impact broiler immunity. Necrotic enteritis, femoral head necrosis, and bacterial chondronecrosis with osteomyelitis (BCO) are common diseases that affect today’s broiler production (Wideman, 2015). As the source of nutrients, feed serves as a modulator of various physiological functions in the intestinal tract, including intestinal barrier function.

Enzymatic digestion

The gut is where endogenous and exogenous enzymes perform their hydrolysis functions to break down complex nutrients into the parts that can be used either by the intestinal tissue itself or for the whole animal. One part of hybrid enzymatic digestion is the fermentation by commensal microbes, in which complex materials form end-products of high biological values (such as short-chain fatty acids, SCFA).

Absorption

Maintaining the gut’s resorptive capacity is essential to secure the total intake of digested nutrients. Otherwise, pathogenic bacteria might use the excess nutrients to grow, form toxins, and affect the birds’ health and productivity.

United microbiome

The intestine of a broiler chicken is colonized by more than 800 species of bacteria and other inhabitants, such as viruses and simple organisms that are still unknown. By competitive exclusion and secretion of bacteriocins (volatile fatty acids, organic acids, and natural antimicrobial compounds), commensal bacteria keep the host safe from an overgrowth of dangerous bacteria (e.g., Salmonella, Campylobacter, and Clostridium perfringens). The fine-tuned diversity in the intestinal flora and balance in all interactions between it, the host, and the ingesta are needed for birds to stay healthy and perform well.

Transport

Birds’ digestive tract volumes are smaller than those of mammals with similar body weight. This means that they achieve more efficient nutrient digestion in a shorter retention time, averaging between 5 and 6 hours. Passing the small intestine usually takes around 3 hours, of which 1 hour is spent in the duodenum and jejunum. Transport times are affected by the feeding system and the extent to which material enters the caeca. Reflux of material from the distal to the proximal small intestine is an important feature that helps digestion and maintenance of a healthy gut.

Immunity

The intestinal microbiota is critically important for the development and stimulation of the immune system. The intestine is the key immunological organ, comprised of myeloid and lymphoid cells, and a site for producing many immune cell types needed to initiate and mediate immunity. Together with the microbiome, dendritic cells induce antigen-specific responses and form immunoglobulin A, which works in the intestinal lumen.

Natural gut health solution for sustainable ABF broiler production

In practice, supporting broiler gut health requires a holistic approach that includes natural feed additive solutions. Phytomolecules are compounds that certain plants develop as defenses mechanisms. Phytomolecules-based solutions should feature prominently in sustainable ABF broiler production approaches due to their advantageous properties:

Enhance digestion, manage variability

Sustainability necessitates efficient resource utilization. Digestion support needs to be a priority to use the available feed in its entirety. This is particularly important if antibiotics use needs to be minimized: a maximum of nutrients should be utilized by the animal; otherwise, they feed potentially harmful bacteria, necessitating antibiotic treatments. Enhancing digestibility is the focus when we are dealing with variable feed materials or feed changes that represent stress to the animal. Selected phytomolecules have proven efficient at improving performance due to enhanced digestion (Zhai et al. 2018).

Work on microbiome and pathogens

The antimicrobial activity of certain phytomolecules can prevent the overgrowth of pathogens in the gastrointestinal tract, thereby reducing dysbacteriosis (Liu et al., 2018) and specific diseases such as necrotic enteritis. Studies on broilers show that they also reduce the adhesion of pathogens to the wall of the intestine. Certain phytomolecules even possess antimicrobial characteristics against antibiotic-resistant pathogens.

Keep gut integrity

Phytomolecules help maintain tight junction integrity, thus preventing leaky gut (Li et al., 2009). As a result, the potential flow of bacteria and their toxins from the gut lumen into the bloodstream is mitigated. Their properties thus make phytomolecules a promising alternative to the non-therapeutic use of antibiotics. 

Trial results: Phytomolecules enhance broiler gut health

To test the efficacy of phytomolecules, we conducted a large-scale field study in Brazil, under practical conditions. The focus was on growth performance, and no growth-promoting antibiotics were used. Lasting 5 months, the trial involved more than 2 million broilers. The birds were divided into a control and a trial group, with two repetitions per group. Both groups were fed the standard feed of the farm. The trial group additionally received 100g of Activo per MT in its finisher feed for 3 weeks. The study clearly shows that Activo supplementation improves performance parameters (daily weight gain, average total gain, and improved feed efficiency), which resulted in a higher production efficiency factor (PEF):

• Activo groups had a 3 % higher average daily weight gain and reached their slaughtering age earlier
• The final weight of Activo groups was about 2.5 % higher than in the control group
• With a 2 points better feed conversion, the animals of the Activo group achieved a 13.67 points higher PEF

Figure 1: Broiler performance results, Activo vs. non-supplemented control group 

Conclusion

Antibiotic-free broiler production is a challenging endeavor: producers need to maintain animal welfare and keep up efficiency while making farming profitable. Over time, these challenges will affect producers even more as sustainability requirements increase across all parts of the broiler production chain. On top of that, coccidiostats, which are essential for efficient broiler production, are increasingly being questioned, which will require concerted research into feed additive solutions.

To make sustainable ABF broiler production the norm, it is unavoidable to adopt suitable strategies related to nutrition, genetics, management, biosecurity, welfare, and food safety. Effective, scientifically and practically proven tools already exist: Thanks to their positive impact on intestinal health, phytomolecules reliably support sustainable broiler production without antibiotics.

References

Cervantes, Hector M. “Antibiotic-Free Poultry Production: Is It Sustainable?” Journal of Applied Poultry Research 24, no. 1 (2015): 91–97. https://doi.org/10.3382/japr/pfv006.

Li, Y., H.Y. Cai, G.H. Liu, X.L. Dong, W.H. Chang, S. Zhang, A.J. Zheng, and G.L. Chen. “Effects of Stress Simulated by Dexamethasone on Jejunal Glucose Transport in Broilers.” Poultry Science 88, no. 2 (2009): 330–37. https://doi.org/10.3382/ps.2008-00257.

Liu, ShuDong, MinHo Song, Won Yun, JiHwan Lee, ChangHee Lee, WooGi Kwak, NamSoo Han, HyeunBum Kim, and JinHo Cho. “Effects of Oral Administration of Different Dosages of Carvacrol Essential Oils on Intestinal Barrier Function in Broilers.” Journal of Animal Physiology and Animal Nutrition 102, no. 5 (2018): 1257–65. https://doi.org/10.1111/jpn.12944.

Wideman, Robert F. “Bacterial Chondronecrosis with Osteomyelitis and Lameness in Broilers: a Review.” Poultry Science 95, no. 2 (2016): 325–44. https://doi.org/10.3382/ps/pev320.

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 (2018): 179–86. https://doi.org/10.1016/j.aninu.2018.01.005.

by Ruturaj Patil, Product Manager Phytogenic Liquids, EW Nutrition

Commercial poultry operations have undergone enormous changes in production practices over the last 50 years. Genetic selection for high production rates, along with upgraded management techniques and dietary measures, have led to increased performance standards in all poultry operations (Kogut et al., 2017). However, it is sensible to now look into whether poultry performance may soon reach a ceiling due to genetic and/or physiological limits. So, aiming at further performance optimization, poultry researchers and producers are now focusing on gut health.

Gut health management is key to sustainably improve poultry performance

The caveat, of course, is that, due to concerns about antimicrobial resistance, antimicrobial growth promoters (AGPs) no longer offer the easy answer to gut health issues they once were. To preserve antibiotics’ efficacy for cases where they are indispensable, gut health-oriented performance enhancement needs to come from other sources. This article reviews the principles of gut health management in poultry and shows how Activo liquid, a phytomolecules-based in-water solution, strengthens poultry performance by targeting gut health.

Gut health: the cradle of poultry performance

Gastrointestinal health in poultry birds encompasses three dimensions: microflora balance, gut structural integrity, and immune system status. The gut plays a vital and diverse role as it hosts most microorganisms in the body, contains more than twenty different hormones, digests and absorbs the nutrients, and accounts for 20% of body energy expenditure (Choct, 2021). When gut health is compromised, digestion and nutrient absorption are affected, with likely detrimental effects on feed conversion, followed by economic loss and greater disease susceptibility.  Disease resistance and nutrient utilization largely depend on maintaining a beneficial gut antioxidant status, improving gut integrity, and modulating the gut microbiota (Oviedo-Rondón, 2019).

In birds, the gut is separated into five distinct regions (Figure 1): crop, proventriculus, gizzard, small intestine (duodenum, jejunum, and ileum), and large intestine (ceca, cloaca, and vent). Each of these regions has a specific role in the secretion of digestive juices and enzymes, the grinding of feed particles and then the digestion and absorption of nutrients (Bailey 2019).

Figure 1: Schematic overview of poultry gastrointestinal tract

Factors affecting gut health

Gut health is influenced by the balance between the physiological health status of host, the gut microbiota, and a range of specific factors, all of which producers need to consider. From a management perspective, key factors encompass deprived gut health, biosecurity, and production stress, which is elevated during certain critical stages (see table 1). Environmental factors include humidity, temperature, and ventilation. Dietary factors, such as feed and water quality, feed composition, and mycotoxin contamination, also impact the development and ongoing state of poultry birds’ intestinal microbiota.

Table 1: Critical stages for gut health issues in poultry birds

The future is here: antibiotic reduction through improved gut health

There is a strong trend towards antibiotic-free (ABF) poultry production, fueled by AGP bans in certain regions (such as the European Union) and increasing consumer interest in avoiding products containing traces of AGPs. ABF systems can be profitable as long as the prices for the final ABF products can cover the investment costs necessary to produce these products. Larger-scale, sustainable ABF production will depend on developing a more profound understanding of intestinal health alongside the development of practical applications that foster gut health throughout each step of the production system.

Feed additive solutions to support birds during challenging situations

Feed additive manufacturers are looking into accessible alternatives to mitigate the need for antibiotics in ABF systems, requiring enormous research and development efforts. At EW Nutrition, our approach is to offer a holistic antibiotic reduction program for gut health management in poultry. The program comprises feed- and water-based solutions to support gut health during high-challenge periods. Activo liquid, an in-water solution containing standardized amounts of selected phytomolecules, is a key component of our program. Based on its three-fold mode of action, Activo liquid provides gut health support that improves livability and feed efficiency:

• Antimicrobial activity hinders the growth of potential pathogens
• Better gut integrity and positive microbiota optimize feed efficiency and gut health
• Antioxidant activity at the gut level prevent free radical formation and oxidative stress

As a water-based solution, Activo liquid provides a quick and flexible option for gut health control on poultry farms. The benefits of Activo liquid supplementation have been demonstrated through several scientific and field studies globally.

Activo liquid reduces mortality and improves feed conversion in broilers

Numerous field studies for antibiotic-free broilers across different countries and breeds show: on average, the inclusion of Activo liquid reduces mortality by 0.6% and improves FCR by 5%, compared to non-supplemented control groups (Figure 2).

Figure 2: Changes in livability and feed conversion rate in Activo liquid-supplemented broilers

Activo Liquid supports broiler breeders from start of lay to pre-peak production

Broiler breeders are prone to gut-related issues from the start of lay to pre-peak production (age 24 to 32 weeks). This period is characterized by sudden changes in feed consumption and high production stress. Field studies from Thailand show that Activo liquid supplementation in this phase leads to improved livability and higher laying rates.

A of 34,000 female broiler breeders during the first 9 weeks of production found that for the group receiving Activo Liquid  (200 ml / 1000 L, 5 days per week, 6 hours per day):

• The average laying rate/HH increased by 7.2 % during the trial period,
• Nearly 3  more  hatching  eggs  per  hen  housed  and  about  5  more  hatching  eggs  than  the  genetic standard were produced, and
• Mortality decreased by 0.2 % points compared to the control.

Another study, again evaluating the first 9 weeks of production using 20,000 birds, also found that broiler breeders supplemented with  Activo  Liquid show reduced mortality, a higher laying rate, and more hatching eggs per hen housed (Figure 3).

Figure 3: Performance results from Cobb broiler breeders, Activo liquid supplementation vs. control

Activo program improves layer productivity

Commercial layers often becomes challenged due to stress originating from management issues, gut pathogens, and an improper assimilation of nutrients. The negative impact on gut health can result in poor uniformity, low livability, and impaired body weight gain. The Activo program (a combination of Activo powder and liquid) has been found to improve layer performance, likely because its phytogenic components foster better intestinal integrity and microbiome diversity.

A study of 8 replicates with 36 Hy-line brown laying hens was conducted in China, for instance, testing the inclusion of both Activo (100 g / MT of feed) and Activo Liquid (250 ml / 1000 L for 4 days, every 2 weeks, from week 15 to week 25). It found that the Activo program  can effectively support the animals in coping with NSP-rich diets (Figure 4). Supplemented layers showed 3.36% higher egg production, representing more than 3.5 eggs and more than 150 grams of additional egg mass per hen housed during the period.  Better  gut  health  in  the  Activo  Program  gut  was evidenced  by  a  better  hen  body  weight ,  as  well  as  higher  yolk  color, lower  FCR, and improved  intestinal morphology parameters.

Figure 4: Performance results from Hy-line layers, Activo program vs. control

Conclusion: future improvements in poultry performance will come from the gut

As the trend towards ABF poultry production gains momentum, a concerted focus on supporting birds’ gut health is key to achieving optimal performance. Multiple field studies of Activo liquid application demonstrate that, due to their antimicrobial and antioxidant properties, the phytomolecules present in Activo liquid effectively support birds’ intestinal health during challenging periods.

In combination with good dietary, hygiene and management practices, phytomolecules offer a potent tool for reducing the use of antibiotics. The inclusion of Activo liquid in their birds’ diets allows poultry producers to achieve better gut health and, thus, stronger performance results in a sustainable way.

References

Bailey, Richard A. “Gut Health in Poultry: the World within – Update.” The Poultry Site, July 6, 2021. https://www.thepoultrysite.com/articles/gut-health-in-poultry-the-world-within-1.

Choct, Mingan. “The Importance of Managing Gut Health in Poultry.” Poultry Hub Australia, November 26, 2014. https://www.poultryhub.org/importance-managing-gut-health-poultry.

Kogut, Michael H., Xiaonan Yin, Jianmin Yuan, and Leon Bloom. “Gut Health in Poultry.” CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 12, no. 031 (October 1, 2017): 1–7. https://doi.org/10.1079/pavsnnr201712031.

Oviedo-Rondón, Edgar O. “Holistic View of Intestinal Health in Poultry.” Animal Feed Science and Technology 250 (2019): 1–8. https://doi.org/10.1016/j.anifeedsci.2019.01.009.

by Inge Heinzl, Editor, and Technical Team, 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.

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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 Dr. Ajay Bhoyar, Global Technical Manager – Poultry, EW Nutrition

Necessity, goes the saying, is the mother of invention. No wonder, then, that necessity is driving innovation in the poultry industry.  A few distinct such drivers of change stand out:

Genetic improvements: Significant genetic improvements have consistently increased the production performance of breeders, as well as commercial broilers and layers. The genetically improved breeds demand improved nutrition and management practices.

Feed ingredient prices/availability: Corn and soybean meal are the main feed ingredients in poultry feed. Consequently any fluctuations in their prices have a high impact on the cost of production of eggs and meat. During the short span of the last 5 years, US corn and soybean meal prices have increased by around 54% and 68%, respectively. The optimum utilization of available feed ingredients and improvements in nutrient availability continue to be the key areas of interest for the poultry industry.

Consumer preference and regulatory changes: In certain geographies, these changes have resulted into 3 major trends in the poultry industry: antibiotics reduction (ABR), cage-free rearing, and food safety. The trend in the production and consumption of antibiotic-free meat products is growing faster than ever across the globe.

Antibiotics reduction (ABR): a key global trend

Apart from veterinary use, antibiotics are used as feed additives —antibiotic growth promoters (AGP) in animal production. Alarming levels of resistance to antibiotics have been reported in countries of all income levels, with the result that common diseases are becoming untreatable, and life-saving medical procedures riskier to perform.  Misuse and overuse of antimicrobials are the main drivers in the development of drug-resistant pathogens. (WHO/ https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance )

Antibiotic-free chicken production has gained a lot of momentum in the recent past. Over the past years, consumer preferences in the US resulted in a significant increase in the production of antibiotics-free (ABF) broiler chicken meat. In effect, the number of birds produced in “no antibiotics ever” (NAE) programs in the U.S. today is now at more than 50 percent (Poultry Health Today, 2019).

The reduction of antibiotic use poses some challenges to poultry producers. Apart from increased capital investment for modifications in feed mills and farms, increase in feed additive cost, the main challenge due to the removal of AGPs from feed can be the reduced production performance of poultry, mainly due to increased gut health issues.

Good gut health is a must for profitable production

“The intestinal health of poultry has broad implications for the systemic health of birds, animal welfare, the production efficiency of flocks, food safety, and environmental impact,” state Oviedo-Rondón (2019). The main challenges for ABF chicken or turkey production fall under the same heading of gut health, in particular the prevention and control of coccidiosis and necrotic enteritis (Cervantes, 2015).

What are the most effective ways to mitigate gut health challenges?

Depending on specific production needs and challenges, various technologies are used by the poultry producers to address gut health issues. Some of the most commonly used innovative technologies include:

Dietary Fibers (DF)

Scientists have found that DF have an enormous impact on the gastrointestinal tract (GIT) development, digestive physiology, including nutrient digestion, fermentation, and absorption processes of poultry (Jha & Mishra, 2021).

The water-insoluble fibers are seen as functional nutrients, as they can escape digestion and modulate nutrient digestion: “A moderate level of insoluble fiber in poultry diets may increase chyme retention time in the upper part of the GIT, stimulating gizzard development and endogenous enzyme production, improving the digestibility of starch, lipids, and other dietary components” (Mateos et.al. 2012). The insoluble DF, when used in amounts between 3–5% in the diet, could have significant effects on intestinal development and nutrient digestibility.

Dietary fibers influence the development of the gizzard in poultry birds.  A well-developed gizzard is a must for good gut health. Jiménez-Moreno & Mateos (2012) noted that the coarse fiber particles are selectively retained in the gizzard, that ensures a complete grinding and a well-regulated feed flow and secretion of digestive juices, and regulates GIT motility & feed intake. The inclusion of insoluble fibers in adequate amounts improves the gizzard function and stimulates HCl production in the proventriculus. Thus it can help in the control of gut pathogens.

Probiotics and prebiotics

Probiotics and prebiotics have drawn considerable attention as alternatives to antibiotics in animal feeds. Supplementing diets with probiotics and prebiotics is a significant factor contributing to modified intestinal microflora, which, in turn, may effectively influence the birds’ growth performance and health (Yang et al. 2009).

Probiotics introduce desirable microorganisms into the intestinal tract through the diet (feed or water). They consist of live bacteria, fungi, or yeasts that positively contribute to the gastrointestinal flora. As such, they are important for a well-formed and well-maintained digestive system, and are indirectly essential to growth performance and to the overall health of animals in general. Probiotic supplementation could have the following effects, as stated by Jha et al:

• modification of the intestinal microbiota
• stimulation of the immune system
• reduction in inflammatory reactions
• prevention of pathogen colonization
• enhancement of growth performance
• alteration of the ileal digestibility and total tract apparent digestibility coefficient
• decrease in ammonia and urea excretion (Jha et.al., 2020)

Probiotics can be used not just in feed and drinking water, but also in spray solutions applied to day-old chicks either in the hatchery or immediately after placement in the brooding house. This way, the beneficial microorganisms can enter the intestine earlier than through other methods (known as early seeding).

Prebiotics are also a means of increasing the beneficial bacteria in the poultry gut microbiota. Prebiotics like mannan-oligosaccharides (MOS), inulin and its hydrolysate (fructooligosaccharides: FOS), as well as other prebiotics are important contributors to the modulation of the intestinal microflora and stimulating a potential immune response, as well as stimulating the development of beneficial microorganisms. Prebiotics can also help reduce pathogen colonization in the GIT.

Feed enzymes

The role of feed enzymes in promoting the efficiency of nutrient utilization is well recognized. Recent estimates (Adeola & Cowieson, 2011) indicate that feed enzymes saved the global feed market an estimated US $3–5 billion per year. Feed Enzymes can also have a positive impact on gut health.

Among the beneficial effects of feed enzymes are:

• Inactivating anti-nutrients in the feed ingredients
• Unlocking nutrients otherwise unavailable to birds (e.g. Phosphorus from phytic acid)
• Reducing harmful microbial proliferation, depriving detrimental microorganisms of nutrients
• Reducing the undigestible components of feed, the viscosity of digesta, or the irritation to the gut mucosa that causes inflammation.

Enzymes also generate metabolites that promote microbial diversity, which helps to maintain gut ecosystems that are more stable and more likely to inhibit pathogen proliferation (Bedford, 1995; Kiarie et al., 2013). Feed enzymes are heat-sensitive and tend to lose their activity potential during pelleted feed manufacturing. There has been a significant interest in the application of intrinsically heat stable enzymes for more efficient action. Apart from coated feed enzymes, the post pellet liquid application (PPLA) of feed enzymes has increased in the recent past.

Toxin binders & antioxidants

Intestinal health problems can often be preempted, especially in poultry companies with ABF production programs, by mitigating the danger of mycotoxins in feedstuffs and rancid fats (Murugesan et al., 2015; Grenier and Applegate, 2013). Mycotoxins can compromise several key functions of GIT. This often results in decreased nutrient absorption (by decreasing the available surface area), modulation of nutrient transporters, and loss of barrier function (Grenier and Applegate, 2013). Some mycotoxins “encourage” the persistence of intestinal pathogens and thus enhance the possibility of intestinal inflammation.

Rancid fats and oils have been linked to the pathogenesis of enteric diseases (Hoerr, 1998; Butcher and Miles, 2000; Collet, 2005). The oxidation of oils and fats negatively impacts the energy content of these ingredients. The addition of feed antioxidants during the rendering process/ blending of fats and oils, and proper storage and transport before final use in feed can control rancidity in oils and fats. Proper fat storage conditions in tanks and transportation lines should be constantly monitored to prevent the development of rancidity in the feed mill. Antioxidants and mycotoxin binders can reduce the effects of mycotoxins and peroxide, especially, but not only, in ABF programs (Yegani and Korver, 2008).

Organic acids

Organic acids are compounds with acidic properties that occur naturally and include carbon. As the digestive process includes microbial fermentation, beneficial bacteria which naturally reside in the crop, intestines, and ceca produce such organic acids (Huyghebaert et.al. 2010). The inclusion of organic acids in poultry diets can improve gut health, increase endogenous digestive enzyme secretion and activity, and improve nutrient digestibility. Thus they generally contribute to the overall gut health of the animal.

The inclusion of organic acids in feed can help not only decontaminate feed but also have the potential to reduce enteric pathogens in poultry. The acids can cross the bacterial cell wall and disrupt the normal actions of certain types of bacteria, including Salmonella spp, E. coli, Clostridia spp, Listeria spp. and some coliforms.

Organic acids are also used in drinking water to help lower the microbial count. This can be achieved by lowering the pH of water and by the prevention/removal of biofilms in the water lines.

However, organic acids should be included in the feed or water with caution. The limitations for use of organic acids in animal production can be:

• Bacterial resistance to organic acids over long-term use
• Adverse effect on feed palatability, leading to feed refusal
• Organic acids are corrosive in nature and can damage poultry equipment
• Buffering capacity of dietary ingredients can impact efficacy

Essential oils/Phytomolecules

Essential oils (EOs) are raw extracts from plants (herbs, flowers, leaves, roots, fruit etc.). The beneficial effects of EOs include appetite stimulation, improvement of enzyme secretion related to food digestion, and immune response activation (Krishan and Narang, 2014)

EOs are an unpurified mix of different phytomolecules. The raw extract from oregano is a mix of various phytomolecules (terpenoids) like carvacrol, thymol, and p-cymene. Carvacrol, for instance, is a monoterpinoid found in various plants such as oregano or thyme. A phytomolecule is one active compound.

These botanicals have received increased attention as possible growth performance enhancers for animals in the last decade because of their beneficial influence on lipid metabolism, as well as their antimicrobial and antioxidant properties (Botsoglou et al., 2002), their ability to stimulate digestion (Hernandez et al., 2004), their immune-enhancing activity, and anti-inflammatory potential (Acamovic and Brooker, 2005). Many studies have reported on the supplementation of poultry diets with essential oils that enhanced weight gain, improved carcass quality, and reduced mortality rates (Williams and Losa, 2001). The use of specific EO blends can be effective in reducing the colonization and proliferation of Clostridium perfringens and controlling coccidia infections. Consequently, it may also help reduce necrotic enteritis (Guo et al., 2004; Mitsch et al., 2004; Oviedo-Rondón et al., 2005, 2006a, 2010).

Mode of action of phytomolecules

The gut health optimizing mode of action of phytomolecule-based preparations like Activo® (EW Nutrition) can be described as follows:

Digestive

The digestive properties increase the secretion of digestive enzymes and enhance gut motility. A “significant increase in pancreatic trypsin, amylase, and maltase activities in broilers fed different blends of commercial essential oils” has been reported as well (Jang et al., 2007). The essential oils in carvacrol, for instance, have positive effects on growth performance and the intestinal barrier function of broilers. They were also able to support repairing the intestinal damage caused by lipopolysaccharides (Liu et al. 2020).

Antimicrobial

The antimicrobial properties of phytomolecules can impede the growth of potential pathogens. Thymol, eugenol, and carvacrol have been shown to have “synergistic or additive antimicrobial effects when combined at lower concentrations” (Bassolé and Juliani, 2012). In in vivo studies, essential oils used either individually or in combination “have shown clear growth inhibition of Clostridium perfringens and E. coli in the hindgut and ameliorated intestinal lesions and weight loss than the challenged control birds” (Jamroz et al., 2006, Jerzsele et al., 2012, Mitsch et al., 2004).

One well-known mechanism of antibacterial activity is linked to the phytomolecules’  hydrophobic nature. This characteristic helps disrupt the permeability of cell membranes and cell homeostasis. The consequence of this disruption is the loss of cellular components, influx of other substances, or even cell death (Brenes and Roura, 2010, Solórzano-Santos and Miranda-Novales, 2012, Windisch et al., 2008, O’Bryan et al., 2015).

Antioxidant

The antioxidant properties at the gut level prevent free radical formation and oxidative stress. Thymol and carvacrol have been shown to inhibit lipid peroxidation (Hashemipour et.al. 2013), a mechanism leading to the oxidative destruction of cellular membranes (Rhee et al., 1996). This destruction can ultimately lead to cell death and to the production of toxic and reactive aldehyde metabolites, known as free radicals. Among these free radicals, malondialdehyde (MDA) as a final product of lipid peroxidation has often been used for determining oxidative damage (Jensen et al., 1997).  Thymol and carvacrol both have strong antioxidant activity (Yanishlieva et al., 1999). Oregano “added in doses of 50 to 100 mg/kg to the diet of chickens exerted an antioxidant effect in the broiler tissues” (Botsoglou et al., 2002).

It has also been suggested that chicken body oxidative balance can benefit from essential oils. Karadas et al. (2014) fed a blend of carvacrol, cinnamaldehyde, and capsicum oleoresin to Ross 308 broilers, and found a significant increase in the hepatic concentration of carotenoids and coenzyme Q10 at d 21 of age.

Essential oils, or phytomolecules, are highly volatile substances and are susceptible to changes caused by external factors such as light, oxygen, and temperature, in addition to being prone to evaporating. They need to be protected/micro-encapsulated during the process of feed manufacturing. The advantages of matrix encapsulation include

• a slow and gradual release of active ingredients in the digestive tract
• protection of phytomolecules from oxidation and other harsh conditions during feed processing
• prevention of any negative effects on palatability of feed

Above: Micro-encapsulation protecting phytomolecules in feed processing

Apart from use in feed, the liquid phytomolecules preparations for drinking water use can prove to be beneficial in preventing and controling losses during challenging periods of the birds’ life (feed change, handling, environmental stress, etc.).  The liquid preparations have the potential to reduce morbidity and mortality in poultry houses and thus the use therapeutic antibiotics. Barrios et al. (2021) suggested that Activo and Activo Liquid may ameliorate the impact of Necrotic Enteritis on broilers and further hypothesized that the effects of Activo Liquid were particularly important in improving overall mortality.

Conclusion

The prevailing driving forces of the market will continue to challenge the dynamic poultry industry. Still, gut health challenges in ABF poultry production can be alleviated with multifactorial approaches, including changes in nutrition and improved management practices. Innovative feed additive technologies have contributed to reducing production losses triggered by the removal of AGPs in poultry production.

Essential oils/phytomolecules are one such promising technology, with proven benefits in terms of the production performance of poultry. Phytomolecules are generally recognized as safe and are commonly used in the food industry. Some of the phytomolecules combinations have multiple modes of action, supporting an efficient and sustainable reduction in antibiotics use in poultry production.

To make ABF programs successful, however, more attention needs to be given to the whole production system, not only to feed, feed additives or control of a few enteric pathogens. Housing, management, water quality and biosecurity at both breeder and grow-out levels are critical in ABF production.

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