2011 Annual Report
1a.Objectives (from AD-416)
1) Identify environmental influences and management practices that contribute to the colonization of food-borne pathogens in pre-harvest poultry.
2) Identify environmental influences and factors that contribute to necrotic enteritis (NE) including: Clostridium spp. and parasites (Eimeria) that contribute to the onset of disease.
3) Identify prebiotics and symbiotics (lactose, cottonseed, etc.) that can be utilized as pre-harvest intervention strategies, and determine how chlorate and feed additives such as alfalfa control poultry enteropathogen colonization.
4) Identify environmental or management practices that contribute to antibiotic resistance acquisition and dissemination among and between the various pathogenic and commensal microorganisms found in commercial poultry.
5) Characterize the complex interactions between the innate immune and endocrine systems and develop a more fundamental understanding of the role of gastrointestinal endocrinology on the microbial ecology of the gut of food-producing animals.
1b.Approach (from AD-416)
1) Using a newly constructed (i.e., naive) commercial broiler production facility, we will follow bacterial, viral, protozoan, and fungal movement within the facility from prior to the first placement of birds through several successive production cycles. The movement of these organisms within the environment will be mapped using genetic identification and traditional culture methods.
2) Using a necrotic enteritis (NE) in vivo model developed in our laboratory and a primary cell culture model, we will investigate the interactions of Clostridium with other bacterial populations within the gastrointestinal tract of broilers and the development of NE. We will evaluate these bacterial populations using molecular-based techniques (DGGE, PFGE) in order to determine the dynamics between commensal gut bacterial populations and Clostridium. Additionally, we will examine the toxins produced by Clostridium using tissue culture techniques and Multiplex Polymerase Chain Reactions (PCR).
3) The efficacy of lactose, cottonseed, and similar prebiotics and symbiotics will be evaluated under commercial conditions for their ability to reduce food-borne pathogens in poultry. Practical feeding trials will be performed to ascertain the ability of chlorate and alfalfa as alternatives to traditional antimicrobials, and the mode of action of these compounds will be determined. We will also study different quorum sensing autoinducers to determine the effects of biological and synthetic bacterial autoinducer inhibitors on poultry enteropathogens.
4) Utilizing an in vitro bacterial conjugation assay, we will identify flavophospholipol-like compounds (flavophospholipol has been shown to reduce horizontal gene transfer between Enterococci in vitro), that inhibit bacterial conjugation and resistance gene acquisition among gut bacteria.
5) We will characterize specific interactions between the immune and endocrine systems that influence enteropathogen colonization in the gastrointestinal tract of poultry. Microarrays will be utilized to assess fluctuations in key avian hormones that correspond to cytokine expression.
In FY 2011, we concluded monitoring studies of a new commercial poultry facility after completion of 10 broiler poultry rearing cycles that included a facility disinfection and new litter placement. Extensive analyses of fungal and environmental samples for pathogenic bacteria are continuing that will result in a better understanding of the evolution of the poultry microbial environment in commercial production facilities. Project scientists also evaluated a probiotic (mixture of beneficial microorganisms) administered to growing birds, and several disinfection programs to establish if these approaches reduced Clostridium (a pathogenic bacterium) in laying hens and broilers. Preliminary data analysis indicates that the treatments significantly minimized Clostridium infections in the birds; the work is providing a better understanding of how to reduce disease in growing birds. To better understand the relationship between fungi and foodborne pathogens, project scientists identified fungi recovered from commercial poultry operations using a modern molecular biology technique known as rep-PCR. Results from this work will allow the rapid identification of beneficial fungi and will lead to development of assays to select fungi that have antibacterial activity against foodborne pathogens. Molecular biology techniques were used to assess the impact of Salmonella on the endocrine system of poultry; the work identified several factors that are likely involved in bird/Salmonella interactions. In Salmonella and Clostridium vaccine research, we defined optimum parameters for making the bacteria non-infective while maintaining the ability to stimulate a strong antibody response when injected into fertilized eggs subsequently incubated and hatched. Work over the life of this project resulted in significant advances in understanding the ecology and management practices that impact on poultry health and food safety issues. Major strides in identifying dietary additives that can reduce the spread of foodborne pathogens in poultry products that ultimately reach the consumer were made. Project research provided a better understanding of the changes that occur within microbial populations that are associated with commercial rearing of poultry, and has provided a foundation for our ongoing work to develop new technology and protocols for practical use in poultry production that will help improve the microbiological safety of the U.S. poultry and egg supply. This project expired in FY 2011, but was replaced by 6202-32000-032-00D which is continuing and expanding upon the work.
Factors affecting Salmonella load in broiler houses. Broiler chickens reared under conventional commercial protocols often become colonized by Salmonella, which has major human food safety implications. Definitive knowledge is lacking on factors that affect Salmonella entrance and persistence in broiler houses, particularly litter. ARS scientists at College Station, TX, in collaboration with scientists at Mississippi State University, studied parameters associated with broiler house construction and maintenance as they affected Salmonella load. The work established that increased Salmonella presence in litter was associated with the use of wood to construct the base of broiler house walls or to cover the inside of the broiler house foundation. The work also established that increased Salmonella was associated with the use of fresh wood shavings to top dress the old litter between broiler flocks. The cause/effect relationships remain to be fully defined, but this work is important in showing that the composition of broiler house construction materials, and protocols for house maintenance can over time be of significance in minimizing pathogen loads within the houses. Appropriate construction and maintenance procedures can have significant impact in affecting the ultimate microbiological safety of poultry products reaching the consumer.
Modified atmosphere packaging reduces Campylobacter survival on poultry products. Little is known on the effect of storage environment on survival of Campylobacter on raw poultry. ARS scientists at College Station, TX, in collaboration with scientists at Texas A&M University, evaluated the effect of modified storage atmosphere on survival of naturally occurring Campylobacter on processed poultry. The work established that sealing poultry products in a 100% oxygen environment results in reduced levels of Campylobacter (and of spoilage bacteria) during storage at normal retail refrigeration temperature and duration. Campylobacter is one of the leading causes of human foodborne illness in the U.S.; this simple, inexpensive, and easy to implement technology should be of great value in increasing the microbiological safety of poultry products reaching the consumer.
Oviedo-Rondon, E.O., Hume, M.E., Barbosa, N.A., Sakomura, N.K., Weber, G., Wilson, J.W. 2010. Ileal and cecal microbial populations in broilers given specific essential oil blends and probiotics in two consecutive grow-outs. Poultry and Avian Biology Reviews. 3:157-169.
Santos, F., Hume, M.E., Venkitanarayanan, K., Donoghue, A.M., Hanning, I., Slavik, M.F., Aguiar, V.F., Metcalf, J., Reyes-Herrera, I., Blore, P.J., Donoghue, D.J. 2010. Caprylic acid reduces enteric Campylobacter colonization in market-aged broiler chickens but does not appear to alter cecal microbial populations. Journal of Food Protection. 73:251-257.
Beier, R.C., Anderson, P.N., Hume, M.E., Poole, T.L., Duke, S.E., Crippen, T.L., Sheffield, C.L., Caldwell, D.J., Byrd II, J.A., Anderson, R.C., Nisbet, D.J. 2011. Characterization of Salmonella enterica isolates from turkeys in commercial processing plants for resistance to antibiotics, disinfectants, and a growth promoter. Foodborne Pathogens and Disease. 8:593-600.
Byrd II, J.A., Sams, A.R., Hargis, B.M., Caldwell, D.J. 2011. Effect of selected modified atmosphere packaging on Campylobacter survival in raw poultry. Poultry Science. 90:1324-1328.
Stringfellow, K., Caldwell, D.J., Lee, J., Byrd II, J.A., Carey, J., Kessler, K., McReynolds, J.L., Bell, A.A., Stipanovic, R.D., Farnell, M. 2010. Pasteurization of chicken litter with steam and quicklime to reduce Salmonella Typhimurium. Journal of Applied Poultry Research. 19:380-386.
Anderson, P., Hume, M.E., Byrd II, J.A., Hernandez Jr., C.A., Stevens, S., Stringfellow, K., Caldwell, D. 2010. Molecular analysis of Salmonella serotypes at different stages of commercial turkey processing. Poultry Science. 89:2030-2037.
Volkova, V.V., Bailey, R.H., Rybolt, M.L., Dazo-Galarneau, K., Hubbard, S.A., Magee, D., Byrd II, J.A., Wills, R.W. 2009. Inter-relationships of Salmonella status of flock and grow-out environment at sequential segments in broiler production and processing. Zoonoses and Public Health. 57:463-475.
Volkova, V.V., Wills, R.W., Hubbard, S.A., Magee, D., Byrd II, J.A., Bailey, R. 2010. Associations between vaccinations against protozoal and viral infections and Salmonella in broiler flocks. Epidemiology and Infection. 139:206-215.