Project : USDA ARS

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Research Project: Immunological and Practical Approaches to Manipulate the Ecological Niches and Reduce Foodborne Pathogens in Poultry

Location: Food and Feed Safety Research

2022 Annual Report

Accomplishments
1. Nutritional mediated induction of immunity in breeder hens increases immune protection in chicks. Young chicks are susceptible to many different pathogens, including Salmonella, during the first week after hatch. Salmonella colonizes the intestinal tract of young poultry and is one of the leading causes of human foodborne illness. As poultry producers move away from the routine use of antibiotics, there is a growing need to identify alternative approaches to protect and boost the natural immune responsiveness of newly hatched chicks. ARS researchers at College Station, Texas, working closely with industry and academic partners, showed it was possible to confer transgenerational protection against Salmonella colonization in young chicks by feeding the parent hens a diet supplemented with a blend of natural botanicals. This accomplishment demonstrated that by feeding hens a natural antibiotic alternative, the hens produce chicks having a more robust immune response and that are more resistant to colonization by Salmonella. The work represents a significant contribution to the goal of producing poultry products for the U.S. consumer that are microbiologically safe.

2. Non-fecal-oral routes of Salmonella infection in turkeys. As with other poultry species reared commercially for food production, young turkeys are susceptible to colonization by a number of bacterial species that can cause food poisoning in humans if the meat products are contaminated during processing. The turkey industry is in critical need of effective strategies to assure that turkey food products reaching the consumer are microbiologically safe. ARS researchers at College Station, Texas, working closely with key turkey industry scientists and managers, established the various routes by which the growing birds can be infected by Salmonella, one of the more important problematic bacteria. This accomplishment is important because understanding how growing turkeys can be infected by dangerous microorganisms is critical to development of new technology and/or management strategies that will assure microbiological safety of turkey food products. The industry and relevant U.S. regulatory agencies are aware of and highly supportive of this work.

3. Anti-inflammatory mechanism of feeding sub-therapeutic bacitracin to broiler chickens. For decades, poultry farmers fed low levels of antibiotic growth promoters (AGPs) to chickens because the antibiotics seemed to cause increased growth in a shorter amount of time. Although no one understood exactly why antibiotics provided this effect, it was not because the antibiotics killed germs; the doses given to the chicks were much less than the amount needed to kill pathogenic microorganisms. Because consumers have demanded the removal of antibiotics from animal feed to prevent antibiotic resistance in germs that infect humans, there is need for development of alternatives to antibiotics that provide the growth promoting aspects without drug resistance. One of the great stumbling blocks in identifying new alternatives to antibiotics has been the lack of knowledge of how they increased growth of the chicks. ARS researchers at College Station, Texas, identified a potential mechanism of the growth promoting abilities of AGPs: suppressing immune function in the gut. Now that we potentially understand how AGPs work, new alternatives can hopefully be developed that will use these same mechanisms without harming the ability of the chicks to fight infections. These results are important to the poultry industry and to U.S. consumers in providing a new approach to managing harmful bacteria in meat products.

4. Development of a diet-induced low grade chronic inflammatory model in boiler chickens. Until recently, poultry producers have relied on antibiotics to compensate for potential poor husbandry and management issues. However, with the removal of growth-promoting antimicrobials in poultry feed, intestinal inflammation has become more of an issue worldwide. For the poultry producer, chronic low-grade intestinal inflammation has a negative impact on the productivity of the poultry operation by impairing the birds' ability to absorb nutrients and reach 100% of their growth and genetic potential. Although chronic intestinal inflammation can be induced by a number of environmental factors, diet is the main cause given some feed ingredients, such as soybean meal, are potent stimulators of the intestinal immune response. Research into understanding and regulating intestinal inflammation in poultry has been limited by two factors: development of a dependable in vivo model, and identification of non-invasive biomarkers. ARS researchers at College Station, Texas, characterized for the first time two in vivo models of chronic gut inflammation and identified novel inflammation-specific molecules present in the serum and feces that indicate an ongoing inflammatory response. The models will allow studies into methods of controlling inflammation, while the biomarkers will allow for in-the-field diagnosis of inflammation in intensive poultry farming; the work is a major contribution to poultry microbial food safety research.

U.S. DEPARTMENT OF AGRICULTURE

Food and Feed Safety Research: College Station, TX