Meeting Abstract

121-5  Sunday, Jan. 8 09:15 – 09:30  Effects of selenium on the hematology, innate immunity, and metabolic rate of yellow-bellied sliders (Trachemys scripta scripta) HASKINS, D.L.*; HAMILTON, M.T.; STACY, N.I.; TUBERVILLE, T.D.; University of Georgia’s Savannah River Ecology Lab; University of Georgia’s Savannah River Ecology Lab; University of Florida; University of Georgia’s Savannah River Ecology Lab david.haskins@uga.edu

Selenium (Se) is a naturally occurring, essential element that can be toxic to vertebrates in high concentrations. Despite studies that have shown that reptiles can accumulate copious amounts of Se in the wild, little is known on toxicologic effects of Se. In this study, we exposed 70 juvenile yellow-bellied sliders (Trachemys scripta scripta) to seleno-L-methionine via oral gavage for a total of five weeks. Turtles were placed into one of three treatment groups (control, n = 24; 15mg/kg, n = 23; and 30 mg/kg, n = 23). At the conclusion of the experiment, turtles were sacrificed and kidney, liver, muscle, and blood samples were collected for Se analysis. Turtles in the Se treatment groups accumulated significantly higher amounts of Se in all tissue types relative to controls. Although toxicity thresholds for reptiles do not exist, selenium concentrations in both Se treatment groups exceeded avian toxicity thresholds in liver tissues. We found that oxygen consumption and innate bactericidal capacity were not impacted by Se exposure. However, turtles in the 30 mg/kg group exhibited anemia and evidence of immunosuppression (i.e., decreased absolute lymphocytes), which have been described in other vertebrates in response to Se exposure. Furthermore, exposure to the 30 mg/kg Se treatment resulted in 17% (4/23) mortality of juvenile T. scripta. To our knowledge, this study is the first to report Se-induced immunosuppression or mortality in a reptilian species.