Submitted to: Proceedings of Allen D Leman Swine Conference
Publication Type: Proceedings
Publication Acceptance Date: September 21, 1997
Publication Date: N/A
Technical Abstract: Pigs may experience a number of stressful situations during their 25-26 weeks of life: weaning, handling, mixing, transportation, and slaughtering. Stress is a broad-based term which has been used to identify a range of situations which alter an animal's homeostasis. Homeostasis is an integrated process involving interactions among nervous, endocrine, and immune systems. Neuroendocrine-derived factors, such as glucocorticoids and catecholamines, are believed to have a direct effect on immune function. In addition, immunocytes secrete cytokines, such as IL-1 and TNF alpha, which affect the neural system. It is believed that stress induces Salmonella-free pigs to be more susceptible to Salmonella infection, carrier animals to begin shedding again, and persistent shedders to excrete Salmonella at higher numbers. Transportation of pigs is known to cause varying levels of stress, depending on a number of factors, such as crowding, temperature, social status, and duration of trip. On-farm studies to determine the effects of transport stress on Salmonella shedding can be very problematic. Only a few groups have studied the effects of transportation stress and/or feed withdrawal on Salmonella shedding in swine; results have been mixed. Recently, a porcine stress model has been developed that utilizes a glucose analog, 2-deoxy-D-glucose (2DG), to stimulate physiological stress. The study of stress-induced immune modulation and its relation to salmonellosis in swine should be greatly facilitated by this 2DG porcine stress model.