PW09 Pesticide I
8:00 AM - Wednesday
(PW143) Embryonic growth and development in American alligators (Alligator mississipiensis) from contaminated habitats in central Florida.
Rauschenberger, R1, 2, Wiebe, J1, 2, Buckland, J1, 2, Sepulveda, M1, Gross, T1, 2, 1 University of Florida, Gainesville, Florida, USA2 USGS, Gainesville, Florida, USA
ABSTRACT- American alligator ( Alligator mississippiensis) populations from organochlorine pesticide (OCP) contaminated habitats in central Florida have higher OCP burdens in their eggs and higher rates of embryonic mortality compared to populations from reference sites. The objective of our study was determine if altered growth and abnormal development were associated with dead or moribund alligator embryos, and to determine if alterations in embryonic growth and development were associated with OCP exposure. A total of 952 embryos from 54 clutches were collected across three OCP contaminated sites and one reference site. Two eggs were sacrificed from each clutch to establish embryonic age and to collect yolk samples for determination of OCP burdens. Viable eggs from each clutch were randomly and evenly assigned to either a hatch rate group or a developmental study group. Eggs were candled routinely to monitor embryo viability and all dead embryos were collected for morphometric analyses (eye length, head length, total length, and body mass) and histopathology. For the developmental group, live embryos (n= 4/stage/clutch) were collected at developmental stages corresponding to periods of increased mortality as determined from previous studies by our laboratory and processed the same as moribund embryos. Among all sites, dead embryos were smaller in size and mass compared to live cohorts of the same chronological age, with many dead embryos being developmentally retarded and edematous. For live embryos, 16% had liver lesions, 5% had lesions in skeletal muscle, and 3% had kidney lesions, with no differences in lesion prevalence between reference and OCP contaminated sites. With respect to morphometric analysis of live embryos from selected stages, embryos from OCP contaminated sites were greater in body mass than those of reference sites, and embryos from reference sites had greater head length-to-body mass ratios than those of OCP contaminated sites. When conducted independent of site, linear regression analyses between OCP burdens in eggs and morphometric parameters yielded inconsistent results, with some parameters at certain stages being correlated with OCP burdens while others were not, suggesting other factors may be involved. Future studies will examine embryo growth and development as a function of nutritional content of eggs and maternal characteristics, as well as OCP burdens.
Key words: embryo, reptile , organochlorine, development