A Nutritionist’s Perspective on the Removal of Antibiotics in Poultry Production


Antibiotic-free (ABF) poultry production is increasing due to consumer demand. The challenge for the commercial poultry nutritionists is to achieve the same end performance in a cost efficient manner under an ABF system as under regular production practices. A well-planned ABF broiler production nutrition system should include preparatory steps such as maternal nutrition and in ovo interventions to improve viability of embryos and progeny as well as 18+ days of downtime between two successive broiler flocks. Maintaining the normal gut health of broilers through the grow-out is the nutritionists and veterinarians main goal. In this regard, the most challenging aspects are the control of coccidia and in turn prevention of necrotic enteritis. The long-term success and sustainability of any company’s ABF program hinge upon the degree to which these issues are addressed. Other items to be considered to maintain normal gut health in the ABF program are a combination of prebiotics, probiotics, natural chemicals and risk management of mold toxins. Flock mortality may still spike up occasionally in which case nutritionists and veterinarians should have backup treatment plans ready.


Based on a survey reported by Rennier, 12% of the US broiler-feed produced in 2015 was associated with “no antibiotics ever” programs (Rennier, 2016). Several major companies have antibiotic-free (ABF) broilers in their portfolio at various levels. Two prominent examples being Purdue Farms’ and Fieldale Farms, both of which are 100% ABF. These early adopters have proven that the system is a viable and sustainable model in the US food industry.

Tyson Foods has announced its plans to reach complete ABF status in 2017. In 2016 Pilgrim’s Pride added at least one million broilers per week to its already existing ABF capacity and in 2017 plans are underway to add another 2.5 million broilers per week to its ABF portfolio to reach over 25% of all of its broiler production under an ABF system. In anticipation of a significant shift in the market, most commercial poultry companies in the US are developing several options for the future and expect their veterinarians, nutritionists, and managers to be up to date with the technical- /scientific developments and field observations occurring in the area of producing poultry in a totally antibiotic-free system.

Most US companies are better prepared for ABF production

Use of antibiotics has been an established practice for several decades, however, many companies in the USA have been implementing the judicious use of antibiotics over the past ten years or so (Cervantes, 2015). Usually, feeds of several US broiler companies contain limited or even no antibiotics post 35 days of age even in their conventional program.

This conservative use of antibiotics is enabled by improved management practices such as stricter adherence to longer downtimes (at least 14 days) between flocks, investing in broiler housing facilities with better ventilation, improved vaccination and health programs, and improved digestible efficiency of feed ingredients have enabled broilers to remain healthy under low antibiotic conditions. In a way, the US poultry industry has been inadvertently prepped for a successful transition into an ABF broiler production system. However, removing antibiotics completely is still a major challenge and the discussion below is focused on nutritional considerations to facilitate normal gut health.

Role of nutrition and gut health on the performance in poultry raised without antibiotics

Normal gut health is very important for cost efficient poultry production. Achieving normal gut health is relatively easier when a combination of coccidiostats and antibiotics are used. In the current system, nutritionists focus mainly on traditional nutrition work such as feed ingredient quality, nutrient specifications, ingredient costs, least cost formulation etc. However, to achieve normal gut health in an ABF system requires more involvement on the nutritionist’s part.

Nutritionists should work with veterinary groups and field management teams to understand and implement key processes to improve health in all vertical aspects of production such as growing healthy hen flocks to produce strong, clean hatching eggs, interventions during incubation in the hatchery to maintain good embryo health, sufficient downtime between successive broiler flock placements to reduce pathogenic stress, cocci control strategies, broiler house readiness, brooding, and nutritional strategies during hatching egg production as well as during embryo and broiler grow-out. In other words, normal gut health in an ABF system is the result of a holistic approach consisting of appropriate steps upstream and during production.

Learning curve

In the absence of antibiotics, highly complex microbiome management appear to be the key to achieving normal gut health and at present, our knowledge is very limited in poultry microbiome management. The decrease in broiler performance is significant due to disruption in microbiome damage caused by pathogenic microbes when companies switch their broiler program to ABF without streamlining the entire vertical process flow. In Figure 1, monthly data over a year for the first-week mortality under a regular program with antibiotics use in the hatchery as well as in the feed is compared to a “no antibiotics ever” (NAE) program where antibiotic was not used in the hatchery or in the feed. The first-week broiler mortality increased from about 0.9% under the regular program to 1.75% range under the ABF program. The same complex also experienced a deterioration of about 6 points (Figure 2) in feed conversion ratio for a 5 lb.

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(2.27 kg) broiler mainly due to necrotic enteritis, which usually comes as a result of cocciodial originated lesions. The feed cost alone for producing live broiler increased by $0.05/lb ($0.11/kg). Other costs such as grower compensation increased as well.

Key nutritional opportunities (challenges) in antibiotic-free poultry production and possible solutions

As noted above, the performance could be off in an ABF program if it is not well thought out vertically and horizontally. The challenge for nutritionists is to achieve the same performance in an ABF system as in the conventional poultry grow-out in a cost efficient manner. The discussion below starts with the maternal (breeder hen flock) and in ovo nutritional considerations within the hatchery even though hens and broiler embryo growth are outside of the ABF system. A sustainable, cost effective ABF program implementation will involve careful and well thought out process improvement steps from parents to progeny and throughout broiler grow-out, as described in the following section.

1. Nutritionists should explore maternal nutrition as a very economical way to improve hatching egg quality and viability of chick embryo and progeny in their ABF system, including:

a. Nutritional supplementation of Vitamin E, selen­ium, zinc, antioxidants, n-3 and n-6 fatty acids. In the designer egg production, nutritionists are able to increase the contents of vitamin E, zinc, and various other nutrients in the egg (Schideler et. al., 2010). Similar approaches should be used to improve some key nutrients in hatching eggs as well. Research has shown that just supplementing antioxidants such as ethoxyquin and BHT in feeds would increase vitamin E and selenium content of eggs. In addition, using higher levels of vitamin E, n-3 and n-6 fatty acids, selenium and zinc bound to organic molecules will help increase concentrations of these nutrients in egg and increases the possibility of the higher viability of embryo and progeny (Cherian, 2015; Surai, et al., 2016).

b. Pre- and probiotics (direct fed microbials, or DFM) should be used in feeds to help improve gut health and to reduce pathogenic microbes which in turn help produce cleaner eggs (Griggs and Jacob, 2005). Basic criteria to select pre- and probiotics are discussed later in this article.

c. Larger particle limestone usage in the feed would help improve egg shell quality and improve the livability of hens.

d. Feed digestibility can be improved by using exogenous enzymes (phytase, NSPase, proteases) to degrade anti-nutritional components in the feed. Use of phytase enzyme and slightly lowering added sodium content of feed will also help to keep the litter (bedding material) drier and thus help egg quality.

e. Biotransformation of mold toxins is an exciting concept and an investment in this technology to manage mold toxin risk makes sense for parents and grandparent flocks. This concept uses enzymes, microbial products, and natural plant products to transform mold toxins and render them harmless to poultry.

2.In-ovo nutrient delivery during embryo growth in the hatchery. This technique could be used to improve immune functions (Dibner et al., 2008) of broiler chicks. Uni (2014) outlined several nutritional candidates for in ovo feeding that can improve gut health, early growth, improved performance, and meat yield. Although this is not commonly used at present, nutritionists should be exploring possible to identify cost-effective nutritional candidates for this route of delivery to improve gut health and early growth.

3. Coccidia control and prevention of necrotic enteritis is the most important objective in achieving normal gut health in ABF broiler production (Cervantes, 2015). However, various possible options available to achieve this goal are not directly discussed in this article because it is covered in detail elsewhere in this symposium (2017 Animal Nutrition Conference of Canada). Even so, during the discussion of other options- /agents available to achieve normal gut health, it will be noted if they have any side benefits in controlling cocci and necrotic enteritis.

4. Early nutrition (day 1 to the first 7 to 10 days) of broilers, including:

a. With antibiotics and coccidiostats being restricted (excluding some ABF programs which allow ionophores to control coccidia), nutritionists and veterinarians are exploring combinations of prebiotics, probiotics, and plant-derived antimicrobial feed additives. The strategy should be a) to reduce pathogenic microbes, b) to improve food safety (lower Salmonella, Campylobacter) and if possible c) to improve broiler performance as well. With limited money available to spend on feed, it is difficult to achieve all those goals listed under the strategies. Also, with so many vendors and options available, this author recommends working with vendors who not only have solid research backed, consistent product(s) but have strong technical teams that understand the science to support and customize their products and techniques if necessary as the gastrointestinal tract microbiome is a constantly evolving and moving target.

b. We should make sure that feed is highly digestible, pelleted and crumbled optimally. Use of exogenous enzymes targeted to soybean meal, phytase, and NSPases and are more appropriate at this stage.

c. Nutritionists should utilize super-dosing of phytase enzyme in the feed to degrade as much anti-nutritional phytic acid as possible. This consequently leads to less mucin production which then may in turn help reduce necrotic enteritis. A combination of lower “added” calcium with super-dosing of phytase to release plant bound calcium can help lower NE and improve broiler performance (Paiva, et al., 2013).

d. A pre-starter feed could be designed for this phase. Use of synthetic amino acids is highly encouraged to prevent excess protein in the feed which helps to prevent excess ammonia build up in the facility and also provides fewer nutrients in the hind gut for pathogenic microbes.

e. Risk management of mold toxins should be a part of the strategy as well. If toxin binders are used, be cautious to avoid toxin binders that can bind to expensive organic minerals present in the trace mineral premix. Biotransformation of mold toxins may be an option for some ABF systems.

5. Avoid nutrition-related stress during peak cocci cycling which under cocci-vaccination could occur between 14 to 20 days of age. It would be preferable to avoid switching from a crumbled first feed to pelleted second feed during this stressful period. A failure to execute a good cocci control program would lead to necrotic enteritis at this stage or during the third week in broilers. The prebiotic, probiotic and natural antimicrobial feed additive program started in the first feed should be continued in the subsequent feeds but dosage could be lowered if internal research results lead in that direction.

6. Nutritionists should keep exploring natural or synthetic chemicals options that could be beneficial in improving gut health. For example, supplementing feeds with natural betaine may help reduce or moderate cocci lesions and improve performance (Amerah & Ravidnran, 2015).

7. Even with all the extensive planning and its execution, broilers may still occasionally have severe spikes in mortality. Therefore, it is essential to have treatment options available when early signs of increased mortality are observed. One popular option is acidified copper sulfate administered through drinking water. However, it would be desirable to have two or three such effective options readily available with written treatment protocol as well as access to the treatment material and a field team prepared to execute the treatment plan if necessary.

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