养殖银鲳性腺发育规律和性类固醇激素变化

为掌握养殖银鲳的性腺发育规律及其与性类固醇激素水平的关系,本研究采用组织切片技术和酶联免疫吸附法(Elisa),观察养殖条件下银鲳的精巢与卵巢发育特征和血清中性类固醇激素的周年变化,并分析性腺成熟指数(GSI)、肝重指数(HSI)和肥满度(CF)与性腺发育的关系。结果显示,养殖银鲳雌鱼1龄即可发育成熟,成熟卵巢呈一对""形的囊状结构。11月份有近一半个体发育至III期,33.3%已发育至IV期,12月—翌年1月越冬期间约2/3退化至II期,3月又迅速发育至IV期,4月份达到V期并产卵,5月份产卵结束卵巢进入恢复期IV期。银鲳精巢属小叶型,III期精巢出现小叶腔,IV期精巢出现精子,精巢发育速率快于卵巢,即"雄性早熟",7月龄约20%个体可达到性成熟,越冬时退化至III期,3月重新发育,精子分批成熟排精。雌鱼GSI值为0.19%~12.89%,HSI为0.97%~2.30%,CF为2.30~3.08 g/cm~3,雄鱼的GSI为0.08%~2.62%,HSI值为0.73%~1.83%,CF为2.11~2.80 g/cm~3,GSI值在V期时达到最大,HSI和CF值则于IV期达到峰值。雌鱼血清中雌二醇(E2)周年表达水平为23.27~59.13 pg/m L,雄鱼为15.90~36.20 pg/m L,雌鱼的睾酮(T)为14.57~68.67 nmol/L,雄鱼的T为18.62~66.49 nmol/L,E2水平与HSI值呈现显著正相关关系,T表达水平与GSI值呈现显著正相关关系。研究表明,银鲳血清中性类固醇激素含量与精巢和卵巢的发育密切相关,可作为了解养殖银鲳性腺发育的重要指标。

The gonadal development and changes of serum steroid levels of cultured Pampus argenteus

Tissue slicing and enzyme linked immunosorbent assy (ELISA) were conducted to help understand the law of development and the level of sex steriod of farming Pampusar genteus, we observed the developmental characteristics of testis and ovary of Pampusar genteus under breeding conditions and the anniversary changes in serum neutral steroids. The relation of gonads mature GSI, liver weight index CF, fatness HSI and gonad development were also studied. It turned out that breeding females matured at the age of 1, and the matured ovary presented as ">". Nearly half of individuals entered into stage III in November, 33.3% individuals had been developed into stage IV from December to next January during the winter, about 2/3 individuals degenerated to stage II and developed quickly to stage IV in March. In April, P.argenteus reached stage V and spawned. After spawning, the ovary entered into stage IV. The structure of testis is lobular type, lobular cavities appears in stage III of testis, sperm appears in stage IV. The development of testis was faster than that of ovary, which means "male premature". 20% of individuals got sexual maturity after 7 months. During the winter, from December to the next February with decreasing temperature, the testis degenerated to stage III and in March the testis developed again, sperms were experted in different times. GSI of females differed from 0.19% to 16.80%, HSI was from 0.66% to 2.74% and CF ranged from 2.30% to 3.01%. GSI in males rangeed from 0.08% to 2.69%, the value of HSI was from 0.73% to 1.85% and CF was from 2.11% to 2.90%. The value of GSI reached the maximum in the Stage V, HSI and CF reached the peak in stage IV. The content of E2 of female varied from 23.27 to 62.06 pg/ml and the content of E2 of male was 15.90 to 36.81 pg/ml in different develpomental stages and the value of HSI in females showed positive correlation. The content of testosterone (T) in female was from 19.86 to 70.04 nmol/L and that in male was 18.62 to 66.31 nmol/L in different develpomental stage and changes in expression levels of T showed a significant positive correlation. Our research shows that the content of serum steroid hormones was closely related to the development of the testis and ovary and as an important indicator to understand the development of cultured Pampus argenteus gonad in time.