Meeting Abstract

P1.221  Friday, Jan. 4  Assessment of circulating sex steroid hormones and vitellogenin content in male and female breeding spotted gar (Lepisosteus oculatus) MOORE, B.C.*; BRINKMAN, E.; BOGGS, A.S.P; MENDOZA, R.; Louisiana Tech University, Ruston LA; Arkansas Game and Fish Commission, Camden AR; Medical University of South Carolina, Charleston SC; Universidad Autónoma de Nuevo León, Mexico bmoore@latech.edu

Vitellogenesis, a vital component of fish reproduction, has been extensively studied across teleost fishes. However, this process of yolk deposition in eggs has received less of a research focus in holostean fishes, such as gar. Here we collected male and female spotted gar serum and tissue samples from Felsenthal Reservoir, Arkansas in April 2011 during the beginning of the active spawning period. Gonad histology characterized the reproductive state of ovary and testes. We cross-validated an antibody designed against alligator gar (Atractosteus spatula) vitellogenin (VTG) for use with spotted gar samples. Vitellogenin concentrations were measured in serum, liver, and gonad tissues. Using liquid scintillation RIA, we quantified circulating serum concentrations of estradiol and testosterone. Testes were undergoing active spermatogenesis while ovary morphologies included gravid, partially ovulated, and depleted states. Gonad somatic index (GSI) and serum and ovary VTG concentrations were greater in egg-bearing females as compared to females with depleted ovaries and males, while all female liver VTG concentrations were greater than those measured in male livers. Heptosomatic index (HSI) did not vary among fish. Serum testosterone concentrations did not vary among fish and estradiol concentrations were greater in all females as compared to males, regardless of the ovaries egg-bearing state. These results lay a foundation to further characterize spotted gar reproductive physiology and vitellogenesis.