2007 Annual Report
1a.Objectives (from AD-416)
The objectives of this work include: 1)Determine the impact of stress on the immune response and on colonization of foodborne pathogens in turkeys; 2)Optimize strategies for decreasing the impact of stress on colonization
of turkeys with pathogens of food safety importance.
1b.Approach (from AD-416)
We hypothesize that the response to common stressors of commercial turkey production, including Escherichia coli respiratory disease (airsacculitis), moving and transport, and temperature extremes, can increase pre-harvest contamination of turkeys with pathogens of food safety importance, and that basic understanding of how turkey immunity is affected by stress will lead to the development and application of practical strategies to improve product safety. Because stress has been shown to both increase disease resistance at low levels and decrease disease resistance at high or sustained levels, its effects on food safety have been difficult to quantify. We have developed transport stress and cold stress models which result in repeatable levels of stress-induced infection of turkeys with E. coli. We will use these models to study the colonization of turkeys with other bacteria of food safety importance. Cell culture studies of the interaction between bacterial pathogens and primary turkey synovial cells, macrophages, and heterophils, from normal and stressed animals will provide basic data and systems for testing the efficacy of therapeutic and prophylactic products to modulate the stress response, improve disease resistance, and decrease carcass contamination with pathogens. Novel non-antibiotic interventions will include antimicrobial peptides and acute phase proteins that will be developed using exploratory analysis of physiological reactions in our stress models as described in the previous section. These products will be incorporated into stress models; however variations in both dosage and timing relative to stressor will be emphasized in multiple experiments to maximize production gains while minimizing pathogen contamination.
Yeast Extract Stimulates Gastrointestinal Tract Development and Protects Poults from Cold Stress:
Scientists in the Poultry Production and Product Safety Research Unit at Fayetteville, Arkansas, reported that yeast extract supplements may provide an alternative to antibiotics for both the prevention of disease and reduction of pathogen contamination of poultry. Yeast extract supplementation significantly improved intestinal morphological characteristics of poults in two studies and increased the body weights and the feed/gain ratio of cold-stressed, Escherichia coli challenged turkey poults that were the progeny of young hens in their 2nd wk of lay. Turkeys that were the progeny of older hens were not affected by cold stress and challenge, and thus did not benefit from treatment. This research helps to explain the inconsistent effects of antibiotic alternatives in poultry production and suggests that the ability of yeast extracts to improve gut development may make then effective as antibiotic alternatives in stressed birds. (NP108; Pathogen, Toxins and Chemical Contaminants Preharvest, Component 1, 1.1.4, Intervention Strategies).
Evidence that Stress Increases Listeria Monocytogenes Colonization in Turkeys:
There is a critical need to determine the sources of L. monocytogenes contamination of poultry processing plants and products. Scientists in the Poultry Production and Product Safety Research Unit at Fayetteville, Arkansas, showed that L. monocytogenes colonization of turkey knee synovial tissue can be increased by early cold stress and by concurrent infection with Escherichia coli. This research is the first to demonstrate that the stressors associated with turkey production may impact colonization with this environmentally ubiquitous pathogen and contribute to processing plant contamination. (NP108; Pathogen, Toxins and Chemical Contaminants Preharvest, Component 1, 1.1.3, Ecology, Host-Pathogen and Chemical Contaminants Relationship).
Chicken Antimicrobial Peptide (AMP):
AMPs are small proteins that protect against pathogens such as bacteria, fungi, and some viruses. Understanding and manipulating their production and usage may help to boost immunity in poultry and develop better food safety. Proteomic and mass spectrometric approaches were used to purify and identify these protiens that are active in immune functioning cells. Scientists in the Poultry Production and Product Safety Research Unit at Fayetteville, Arkansas, discovered two of these AMP's in poultry: thymosin beta 4 and beta defensin (gallinecin-2). Measurement of these peptides under different physiological and pathological conditions will enable researchers to study their regulation and manipulation to harness their protective effects. (NP108; Pathogen, Toxins and Chemical Contaminants Preharvest, Component 1, 1.1.4, Intervention Strategies).
|Number of invention disclosures submitted||2|
|Number of non-peer reviewed presentations and proceedings||7|
|Number of newspaper articles and other presentations for non-science audiences||2|
Huff, G.R., Huff, W.E., Rath, N.C., Solis De Los Santos, F., Farnell, M.B., Donoghue, A.M. 2007. Influence of hen age on the response of turkey poults to cold stress, Escherichia coli challenge, and treatment with a yeast extract antibiotic alternative. Poultry Science. 86:(4):636-642.
Huff, G.R., Huff, W.E., Rath, N.C., Donoghue, A.M., Anthony, N., Nestor, K.E. 2007. Differential effects of sex and genetics on behavior and stress response of turkeys. Poultry Science. 86(7):1294-1303.
Santos, F., Donoghue, A.M., Farnell, M., Huff, G.R., Huff, W.E. 2007. Gastrointestinal maturation is accelerated in turkey poults supplemented with a mannan-oligosaccharide yeast extract (Alphamune). Poultry Science. 86:921-930.