Author
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Huff, Geraldine |
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Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 2/27/2007 Publication Date: 4/18/2007 Citation: Huff, G.R. 2007. Stress, Wet Litter, and Colibacillosis. In: Proceedings of the 1st Turkey Science and Production Conference, April 18-20, 2007, Macclesfield, UK. p. 19-23. Interpretive Summary: Stress can lead to either an increase or decrease in disease susceptibility. The effects are so variable because they are specific for the type, degree, and duration of stress, are influenced by the complexity of the immune system and the neuroendocrine system, and are strongly influenced by individual differences in physiology and psychology. Turkey osteomyelitis complex (TOC) is a syndrome describing normal-appearing processed turkey carcasses which contain joint, bone, and muscle infections. The presence of a green liver is used as an indicator to remove suspect turkeys from the processing line. We have developed an experimental model for reproducing TOC using a compound that mimics stress and bacterial challenge. This model suggests that stress during production can affect the immune response in fast-growing turkeys making them more susceptible to disease causing bacteria. The first and most dramatic response of turkeys to Dex injection is extremely wet litter. While other factors such as intestinal disease and feed composition play an important role in wet litter problems, the continued selection for faster growing turkey lines may affect the stress response of those turkeys, particularly of male birds, making it ever more important to minimize severe stressors during turkey production. Technical Abstract: Stress can lead to either an increase or decrease in disease susceptibility. The effects are so variable because they are specific for the type, degree, and duration of stress, are influenced by the complexity of the immune system and the neuroendocrine system, and are strongly influenced by individual differences in physiology and psychology. Turkey osteomyelitis complex (TOC) is a syndrome describing normal-appearing processed turkey carcasses which contain lesions including arthritis/synovitis, soft-tissue abscesses, and osteomyelitis of the proximal tibia. The presence of a green liver is used as an indicator to remove suspect turkeys from the processing line. We have developed an experimental model for reproducing TOC using dexamethasone (Dex) immunosupression and E. coli challenge. This model has led to the hypothesis that cumulative environmental stressors affect the immune response in genetically susceptible, fast-growing turkeys leading to susceptibility to colibacillosis and other opportunistic bacterial infections. The first and most dramatic response of turkeys to Dex injection is extremely wet litter. While other factors such as intestinal disease and feed composition play an important role in wet litter problems, the continued selection for faster growing turkey lines may affect the stress response of those turkeys, particularly of male birds, making it ever more important to minimize severe stressors during turkey production. |
