条斑星鲽精巢年周期发育规律和血液性类固醇激素含量变化

采用组织学方法和放射免疫法(RIA)等技术方法,研究了人工养殖条件下条斑星鲽雄性亲鱼精巢发育规律和性类固醇激素的年周期变化规律。实验结果表明,条斑星鲽精巢中可见5个时相的生殖细胞类型,精巢发育可分为5期。条斑星鲽雄鱼GSI值自10月开始升高,12月达峰值(P≤0.05),之后显著下降并保持较低值至下一次生殖周期开始。HSI值在11～12月保持较高表达值,其他各月份保持相对稳定水平。CF值在5～8月保持较高水平,其他月份保持平稳状态。雄鱼血浆中睾酮(T)水平自9月开始升高并在12月(Ⅴ期精巢)达到峰值,其后显著下降并在其后的月份保持较低水平,而雌二醇(E2)在2月出现峰值,其他月份保持相对稳定水平。

Annual maturation of testis correlated with sex steroids level in male barfin flounder broodstocks

The annual maturation cycle of testis and variation of sex steroids level in male barfin flounder were investigated by histological and radioimmunoassay methods. The results showed that gametes exhibited five different phases during the annual development cycle, accordingly the testis maturation cycle can be divided into five stages. The biological parameters including gonadosomatic index (GSI), hepatosomatic index (HSI),and condition factor (CF) were also recorded and they exhibited reasonable variation during the testis maturation. The GSI began to increase in October and peaked in December, and then dropped dramatically and maintained until the next maturation cycle. The HSI value was relatively low during the annual cycle except in November and December. The CF value stayed at a high level from May to August and maintained a relative low level at other months. The serum testosterone level increased from September and peaked in December, then dropped to a relatively lower level until the next maturation cycle. Meanwhile, the serum estradiol level peaked in February and maintained at a relatively low level during the annual maturation cycle. These results highlight the reproductive biology of male barfin flounder, and can serve as useful reference for maturation regulation of male broodstocks.