KAHN, P.F.*; GUYER, C.; MENDON�A, M.T.; Auburn University; Auburn University; Auburn University: Differences in Stress Responsiveness and Immunocompetence in Gopher Tortoises With and Without Symptomatic Upper Respiratory Tract Disease

The gopher tortoise of the southeastern United States has become a threatened species primarily due to habitat infringement. In recent years, however, the tortoises have faced a potentially new threat to their survival, a bacteria that causes Upper Respiratory Tract Disease (URTD). The bacteria�s effects on tortoises range from flu-like symptoms to death. We implemented a study measuring stress responsiveness and immunocompetence on both symptomatic and asymptomatic URTD positive tortoises, as well as URTD negative tortoises, at Ft. Benning Army Base in Georgia. These tortoises came from a variety of habitats deemed impacted or not impacted, depending on the degree of military activity. In a previous study, we found that tortoises from habitats of varying quality (i.e., disturbed and undisturbed) exhibited significant differences in stress responsiveness and immunocompetence. Therefore, we tested whether tortoises of differing health status living in various habitats also exhibit similar responses. Tortoises were bled upon capture to establish baseline levels of corticosterone, a stress response hormone. A standard adrenocorticotropin hormone (ACTH) challenge was then given to assess the responsiveness of the adrenal gland. To quantify the adaptive immune response, tortoises were administered phytohemagglutinin (PHA) and sheep red blood cell (SRBC) challenges to measure T cell and B cell activity, respectively. The PHA response was measured 8-12 hours post-injection, and the SRBC response was measured using a blood sample 20-30 days post-injection. Results of these studies will be related to the URTD status of the tortoises and the habitats in which they live.