Germ Cell Development in the European Eel, Anguilla anguilla L. during the Induction of Spermatogenesis with Human Chorionic Gonadotropin (HCG) PDF

Keywords

freshwater eels, migration, Sargasso sea

Abstract

The migrating immature European freshwater eels, Anguilla anguilla L. undertake extensive migration from Egyptian lagoons to their spawning grounds in the Sargasso Sea . They leave their feeding grounds at an early stage of sexual maturation. Eels hald in seawater were injected at weekly intervals with a human chorionic gonadotropin hormone (HCG) at a dose of 1.5 IU/gBW, and spermatogenesis was studied cytologically. The weekly injections have increased the gonadosomatic index (GSI) from 0.03% to 9.0%. The testicular maturation could be divided into five stages: a stage of seminiferous tubule differentiation (7 days of HCG treatment), a stage of the appearance of cysts of spermatogonia in the testes (15 days of HCG treatment), a stage of intensive spermatogenesis (3 weeks of HCG treatment), a stage of active testicular development (27 days of HCG treatment) and a stage of maximum sexual development (32 days of HCG treatment).