PW01 Wildlife Toxicology
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW002) Refinement of a Reptilian Toxicity Testing System using the Western Fence Lizard, Sceloporus occidentalis.
Heckert, J.1, Salice, C.1, Bazar, M.1, Talent, L.2, 1 U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, Maryland, U.S.A.2 Department of Zoology, Oklahoma State University, Stillwater, Oklahoma, U.S.A.
ABSTRACT- Significant data gaps exist in terrestrial wildlife toxicology. In particular, there are few, if any, reptilian toxicity data. The likely reason for this is the lack of an amenable reptilian test system. The purpose of this study was to further develop and evaluate the use of the Western fence lizard, Sceloporus occidentalis for high-throughput toxicity testing. This species has a number of characteristics conducive to a viable test species. Importantly, S. occidentalis is easily bred and maintained in a laboratory environment thus permitting access to laboratory animals throughout the year. Several important challenges include temperature requirements, diet, and exposure route. A 10-degree temperature gradient within each housing unit was achieved using an electric heating strip. The diet consisted of live crickets dusted with a calcium/vitamin D3 supplement to avoid metabolic bone disease. Multiple exposure techniques were tested to determine the optimal approach. Live, compound-injected crickets were found to be a possible exposure route, but only at sufficiently low volumes. The most effective exposure method was determined to be oral gavage. This method is rapid and assures a complete and accurate dose. Gavage trials with water showed that volumes greater than 0.25 ml were only moderately successful; water was either regurgitated or leaked out of the nostrils. Volumes of 0.15 ml and lower resulted in a nearly 100 percent success. Lizards were amendable to repeated gavage with a volume of 0.05 ml daily for 14 days. This system is being further evaluated using a number of compounds including lead. Preliminary results indicate that this system holds promise for high-throughput reptilian toxicity testing.
Key words: Toxicity, Reptile, Wildlife, Methodology