Induction of Primary Male in Juvenile Red Spotted Grouper Epinephelus akaara by immersion of 17a-methytestosterone

Abstract

At the initiation of an experiment (70 days after hatching,DAH), juvenile red spotted grouper have the paired primordial gonads with somatic cellsbellow kidney in the posterior portion of the body cavity. Formation of ovarian cavityindicates that the ovarian differentiation beginning at 70 DAH in red spotted grouper. At 12months after end of treatment period, control group, 17α-MT 1 mg/L treatment for 4 and 8weeks, and 17α-MT 5 mg/L treatment group for 4 weeks were all female. However,sex-changed males without ovarian cavity were observed in the 17α-MT 5mg/L treatmentgroup for 8 weeks. These results suggested that the red spotted grouper be able to inducethe primary males by hormone treatment prior to gonadal sex differentiation.dicates that the ovarian differentiation beginning at 70 DAH in red spotted grouper. At 12months after end of treatment period, control group, 17α-MT 1 mg/L treatment for 4 and 8weeks, and 17α-MT 5 mg/L treatment group for 4 weeks were all female. However,sex-changed males without ovarian cavity were observed in the 17α-MT 5mg/L treatmentgroup for 8 weeks. These results suggested that the red spotted grouper be able to inducethe primary males by hormone treatment prior to gonadal sex differentiation.