Steroid sex hormone dynamics during estradiol-17β induced gonadal differentiation in Paralichthys olivaceus(Teleostei)  

作　　者：孙鹏 尤锋 刘梦侠 吴志昊 文爱韵 李军 徐永立 张培军 

机构地区：[1]Institute of Oceanology,Chinese Academy of Sciences [2]Graduate School of Chinese Academy of Sciences [3]Shandong Provincial Mari-culture Institute

出　　处：《Chinese Journal of Oceanology and Limnology》2010年第2期254-259,共6页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(No.30571445);the National High Technology Research and Development Program of China(863 Program)(No.2006AA10A404);the Earmarked Fund for Modern Agro-Industry Technology Research System,China(No.nycytx-50)

摘　　要：Steroid sex hormones, such as estradiol-17β （E2） and testosterone （T）, are important regulators of sex change in fish. In this study, we examined the effects of E2 treatment on the dynamics of E2 and T during gonadal differentiation in the olive flounder Paralichtbys olivaceus using histology and radioimmunoassay （RIA）. Flounder larvae were divided into five groups （G0~G4）, and fed with 0 （control）, 0.2, 2, 20 and 100 mg E2/kg feed from 35 to 110 day post hatching （dph）. Fish growth in the G1 and G2 groups was not significantly different from that of the control group （P〉0.05）, while fish in the G3 and G4 groups were less active and showed growth depression and high mortality. The gonads of fish in the G3 and G4 groups were smaller and surrounded by hyperplastic connective tissue. The frequency of females in the G0-G4 groups was 54.5%, 75.0%, 100%, 100% and 93.3%, respectively. The RIA analyses of E2 and T showed that T levels decreased during gonadal differentiation, and increased slightly at the onset of ovarian differentiation, while E2 levels increased gradually and peaked at the onset of ovarian differentiation in the control group. In the E2-treated groups, T levels decreased before the onset of ovarian differentiation. E2 levels were high on the 48 dph, but declined to a lower level on the 54 dph, and then increased gradually during gonadal differentiation. And a sharp increase of E2 levels were observed in all E2-treated groups at the onset of ovarian differentiation. The data suggest that T and E2 play important roles during gonadal differentiation, and an E2 dose of 2 mg/kg feed could induce sex reversal in P olivaceus.Steroid sex hormones,such as estradiol-17β(E2)and testosterone(T),are important regulators of sex change in fish.In this study,we examined the effects of E2 treatment on the dynamics of E2 and T during gonadal differentiation in the olive flounder Paralichthys olivaceus using histology and radioimmunoassay(RIA).Flounder larvae were divided into five groups(G0–G4),and fed with 0 (control),0.2,2,20 and 100 mg E2/kg feed from 35 to 110 day post hatching(dph).Fish growth in the G1 and G2 groups was not significantly different from that of the control group(P>0.05),while fish in the G3 and G4 groups were less active and showed growth depression and high mortality.The gonads of fish in the G3 and G4 groups were smaller and surrounded by hyperplastic connective tissue.The frequency of females in the G0–G4 groups was 54.5%,75.0%,100%,100%and 93.3%,respectively.The RIA analyses of E2 and T showed that T levels decreased during gonadal differentiation,and increased slightly at the onset of ovarian differentiation,while E2 levels increased gradually and peaked at the onset of ovarian differentiation in the control group.In the E2-treated groups,T levels decreased before the onset of ovarian differentiation.E2 levels were high on the 48 dph,but declined to a lower level on the 54 dph, and then increased gradually during gonadal differentiation.And a sharp increase of E2 levels were observed in all E2-treated groups at the onset of ovarian differentiation.The data suggest that T and E2 play important roles during gonadal differentiation,and an E2 dose of 2 mg/kg feed could induce sex reversal in P.olivaceus.

关 键 词：olive flounder gonadal differentiation estradiol-17β （E2） testosterone （T） exogenous E2 treatment 

分 类 号：S917.4[农业科学—水产科学]