Induction of Female-to–male Sex Change in the Honeycomb Grouper (Epinephelus merra) by 11-ketotestosterone Treatments

• DOI: 10.2108/zsj.23.65
• Publication Date: 2006-03-17T05:57:23Z
• Authors: Ramji Kumar Bhandari; Mohammad Ashraful...; Kiyoshi Soyano; Masaru Nakamura
• Keywords: Sex change; Hermaphrodite; Sex reversal; Sexual Differentiation

The honeycomb grouper, Epinephelus merra, is a protogynous hermaphrodite fish. Sex steroid hormones play key roles in sex change of this species. A significant drop endogenous estradiol-17beta (E2) levels alone triggers female-to-male change, and the subsequent elevation 11-ketotestosterone (11KT) correlates with progression spermatogenesis. To elucidate role an androgen we attempted to induce by exogenous 11KT treatments. 75-day treatment caused 100% masculinization pre-spawning females. Ovaries control (vehicle-treated) fish had oocytes at various stages oogenesis, while gonads 11KT-treated transformed into testes; these contained spermatogenic germ cells stages, including accumulation spermatozoa sperm duct. In sex-changed fish, plasma E2 were significantly low, both testosterone (T) increased. Our results suggest that plays important grouper. Whether mechanism 11KT-induced acts through direct stimulation spermatogenesis ovary or via inhibition estrogen synthesis remains be clarified.