Preliminary evaluation of deslorelin, a GnRH agonist for contraception of the captive variable flying fox Pteropus hypomelanus

BACKGROUND:This study was conducted to study the effects of a gonadotropin-releasing hormone (GnRH) agonist, deslorelin, on luteinizing hormone (LH), testosterone (males), semen characteristics and pregnancy in the variable flying fox Pteropus hypomelanus. STUDY DESIGN:Male (n = 3) and female (n = 5) bats received a 4.7-mg implant and were housed with untreated bats (eight females and three males, respectively). Plasma was collected twice monthly and analyzed for hormone concentrations, and semen was collected from untreated and treated males 1 month preimplantation, 3 months postimplantation and 4 months postimplantation. RESULTS:Administration of a GnRH challenge 1 month postimplantation showed an attenuated response in treated (n = 4), but not in untreated (n = 4), male and female bats. Plasma LH was lower in treated versus untreated males (p = .04), but not in females. Testosterone was lower in treated versus untreated males (p < .001). Spermic ejaculates were obtained from treated males, although no untreated females became pregnant during the 8-month study. One treated female became pregnant 6 months after implantation. CONCLUSION:Deslorelin is a useful and reversible contraceptive for P. hypomelanus.