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Improve current understanding of the relationship between stress and the pathogen-host interaction by utilizing a swine neuroendocrine model to modulate the hypothalamic-pituitary-adrenal axis along with a disease challenge model.
A model demonstrating a classic behavioral & physiological stress response by injecting a stress hormone (corticotrophin releasing hormone or CRH) directly into the brain has been developed in the pig. The use of this CRH
model provides a highly controlled situation reflective of the stresses that pigs experience in production situations (transport, temperature changes, moving, mixing, social stress). Weaned pigs are surgically fitted with a brain cannula. After pigs are recovered, they are moved into two
separate rooms in individual cages. Control pigs receive icv saline and test pigs receive either 50 ug CRH or CRH plus an antagonist (Astresin, which is a CRH antagonist). Immediately after the drug treatment, all pigs will be challenged with E. coli or Salmonella. Fecal samples are collected throughout the study. At the end of 3 days pigs are euthanized by an overdose of barbituate and tonsils, illeocecal lymph nodes, intestinal tissue and intestinal contents will be sampled and enriched to determine populations of Salmonella and E. coli.