Raising Healthy Birds without Antibiotics


Recent consumer and food service demand for broilers raised without antibiotics has led to dramatic changes in how gut health is managed. In the past, ionophores and antibiotics with anti-clostridial effects were used to compliment the need in controlling coccidiosis and necrotic enteritis (NE). In the “No Antibiotics Ever (NAE)” arena, coccidiosis must be controlled through traditional anti-protozoal products or coccidiosis immunization. However, success will be determined by finding products to provide anti-clostridial effects or otherwise positively influence microflora balance. The most commonly used antibiotic alternative products in NAE production usually fall in the categories of probiotics, prebiotics, phytogenics/essential oils, or organic acids. Success in NAE production will likely involve a combination of these alternative products along with managing the ever-present Eimeria spp. to achieve satisfactory feed conversion and mortality.


Antibiotic-free production, in contrast to conventional production with some prophylactic antibiotic use, necessitates a keen re-evaluation of chick quality and gut health. Chick quality issues will more common result from gram negative organisms and recontamination issues through in ovo vaccination. Attention to breeder farm hygiene, nest pad maintenance, and farm grading and storage are imperative to improving chick quality. On the hatchery side, hatch window timing and incubation conditions that favor navel closure are critical. Continuous attention to chick quality is even more paramount in producing healthy antibiotic-free broilers.

The key determinant of success in antibiotic-free broilers is control of necrotic enteritis (NE). While other endemic diseases may still remain, necrotic enteritis is the primary disease of increased incidence during this transition. Control of coccidiosis in an NAE program is done via anti-protozoal products or vaccines for the prevention of coccidiosis. Both intervention strategies have their shortcomings, but in the experience of the author, coccidiosis vaccines have a much greater preponderance for necrotic enteritis breaks that exceed a tolerable threshold for mortality that would meet a proposed NAE audit scheme. The key to success in NAE production is finding products and strategies that complement previously known successful programs in coccidiosis and Clostridium perfringens (CP) control.

Mechanisms and Decision Making

Controlling necrotic enteritis requires products that can ameliorate either coccidiosis or C. perfringens. The newest range of products on the market fulfilling the void of antibiotics are probiotics, prebiotics, phytogenics/essential oils, and organic acids. The difficulty that is presented is evaluating the products in a research or field setting as virtually all products do not have true health claims and are sold as “flavouring agents.”

As a result, there are several key components in dealing with NAE product evaluation:

  1. Understanding modes of action and complementing roles
  2. Research and field trials
  3. Defining “success”
  4. Cost vs. benefit analysis

Modes of action

Gut health antibiotic alternatives have a variety of modes of action against Clostridium spp, Eimeria spp, and protective or flora modulating effects. Both single-strain and multi-strain probiotics have been proven to reduce NE by reduction of intestinal CP levels (Jeong, 2014 and Mohnl 2010.)

Additionally, prebiotic products have been demonstrated to have indirect and direct effects on binding pathogenic bacteria and supporting the growth of beneficial bacteria, adding an additional pathway to combat necrotic enteritis and other conditions. These products have been readily available for over 10 years, and have found their value and niche within conventional and NAE programs.

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Perhaps the greatest increase in gut health antibiotic alternative product offerings in the past 5 years has been in the field of organic acids and phytogenic/botanical/EO products. Botanical extracts alone or in combination with organic acids have shown to improve intestinal integrity and control CP-induced NE (Grilli 2015, Lee 2013, Timbermont 2010.) These products appear to not only have anti-clostridial effects, but additionally anti-protazoal shedding effects in the case of certain compounds. But compared to probiotic and prebiotic compounds, botanicals for the most part carry a higher price per ton and do not offer any additional claims of efficacy given their approval status.


Therein lies the greatest struggle of No Antibiotics Ever (NAE) production: understanding your gaps in protection against necrotic enteritis and determining the most cost effective means of achieving this under research and field conditions.

Retrofitting existing in-house research facilities to reflect field conditions and NAE programs must be done quickly and accurately. Coccidiosis products and management strategies in such facilities should emulate a level of coccidiosis and necrotic enteritis challenge that will be observed in the field. There is also a wide chasm between the needed speed of discovery and the availability of trial space in commercial and University settings and turnaround of results.

Field studies, although fraught with variabilities in season and other program changes, should be structured so that, at minimum, tracking mechanisms are in place to determine when products reach the field and are withdrawn. Size, scale, and replicates, are distinct advantages if one has the discipline to stick with programs over growout cycles without incessant adjustment of product inclusions and replacements.


Although cost is the primary driver for any integrated operation, additional factors have impacted the relative “success” of NAE programs. Consideration must be given for the cost of removal of a house or flock from an NAE program and how this flock will be relegated to a different product stream within a processing plant and retail or food service distribution.

Participating companies often have a mortality/morbidity threshold for treatment with an antibiotic therapy when palliative or therapeutic antibiotic alternative products have failed. Reaching this “threshold” in some locations may greatly influence the willingness to evaluate and purchase certain alternative products. So while cost is always a consideration, the game has certainly changed in terms of value and preventative efforts that will be employed to avoid product segregation down the line. Using all the available tools and strategies that exist today, reaching mortality and performance levels of conventional broiler production is certainly possible for many operations and presents a new challenge for those that wish to provide a product the customer desires.

Science & Solutions Special - ABF Poultry

Science & Solutions Special - ABF Poultry

This article was published in our Science & Solutions Special (ABF Poultry)

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Grilli, E., B. Tugnoli, J. Passey, C. Stahl, A. Piva, A. Moeser. 2015. Impact of dietary organic acids and botanicals on intestinal integrity and inflammation in weaned pigs. BMC Vet Res 11:96

Jeong, J.S., I. Kim. 2014. Effect of Bacillus subtilis C-3102 spores as a probiotic feed supplement on growth performance, noxious gas emission, and intestinal microflora in broilers. Poult Sci 93 (12): 3097-3103

Lee, S. H., H. Lillehoj, S. Jang, E. Lillehoj, W. Min, D. Bravo. 2013. Dietary Supplementation of young broiler chickens with Capsicum and turmeric oleoresins increases resistance to necrotic enteritis. Brit J Nutr. 110 (5): 1-8

Mohnl, M. 2010 Inhibition of Clostridium Perfringens through Probiotic Strains and Efficacy of Mulispecies Probiotic to Reduce NE in Poultry. Avian Pathology S20.

Timbermont, L., A. Lanckriet, J. Dewulf, N. Nollet, K. Schwarzer, F. Haesebrouck, R. Ducatelle, F. Van Immerseel. 2010. Control of Clostridium perfringens-induced necrotic enteritis in broilers by target released butyric acid, fatty acids, and essential oils. Avian Path. Vol 39 : 117-121

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