title: Induction of Primary Male in Juvenile Red Spotted Grouper Epinephelus akaara by Immersion of 17α-Methyltestosterone.
abstract: We investigated the androgenic effects of 17α- methyltestosterone (MT) on gonadal sex reversal in juvenile red spotted grouper Epinephelus akaara. The fish were immersed in 17α-MT at 1 and 5 mg/L. Treatment method of 17α-MT was once weekly for 4 and 8 weeks. Fish were sampled at 12 months after end of the treatment period in order to histological analysis. At the initiation of an experiment (70 day after hatching), juvenile red spotted grouper have the paired primordial gonads with somatic cells bellow kidney in the posterior portion of the body cavity. Formation of ovarian cavity indicates that the ovarian differentiation beginning at 70 DAH in red spotted grouper. At 12 months after end of the treatment period, control group, 17α-MT 1 mg/L treatment group for 4 and 8 weeks, 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 5 mg/L treatment group for 8 weeks. In grouper, we firstly reported that the red spotted grouper be able to induce the primary males by hormone treatment prior to gonadal sex differentiation.
authors.affiliation: CR Co., Ltd., Jeju 695-965, Korea.
authors.forename: Chi-Hoon
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Marine Science Institute, Jeju National University, Jeju 695-965, Korea.
authors.forename: Sang-Woo
authors.initials: SW
authors.lastname: Hur
authors.affiliation: Jeju Technopark, Jeju 699-121, Korea.
authors.forename: Oh-Soo
authors.initials: OS
authors.lastname: Na
authors.affiliation: Department of Marine Biology, Pukyong National University, Busan 608-7387, Korea.
authors.forename: Hae-Ja
authors.initials: HJ
authors.lastname: Baek
authors.affiliation: East Sea Research Institute, Korea Institute of Ocean Science and Technology, Uljin 767-813, Korea.
authors.forename: Choong-Hwan
authors.initials: CH
authors.lastname: Noh
authors.affiliation: Educational Science Research Institute, Jeju National University, Jeju 690-756, Korea.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Han
authors.affiliation: Marine Science Institute, Jeju National University, Jeju 695-965, Korea.
authors.forename: Young-Don
authors.initials: YD
authors.lastname: Lee
keywords: Epinephelus akaara; Gonadal sex differentiation; Primary males; Red spotted grouper; Sex change