【摘要】 采用常规解剖学和组织学方法,研究人工养殖条件下云南盘鮈(Discogobio yunnanensis)成鱼性腺发育及周年变化情况,为其全人工化繁殖提供基础资料。实验时间为2016年6月至2017年6月,每月中旬解剖成鱼取性腺,雌雄各5～8尾,活体状态下测量常规生物学数据,解剖后肉眼观察性别及性腺发育情况,并记录色泽等其他外形特征。取性腺称重并测量其长度和宽度,计算其性腺成熟系数(GSI),观察其性腺发育状况。结果表明,云南盘鮈在人工养殖条件下可以性成熟,并能繁殖后代。卵巢发育可分为Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ期,Ⅱ期卵巢持续时间最长(6-11月),11月开始出现Ⅲ期卵巢,12月主要为Ⅱ、Ⅲ期卵巢,次年1-3月主要为Ⅲ期卵巢,4-5月主要为Ⅳ期卵巢,5月底达到Ⅴ期即成熟期,排卵后进入短暂的Ⅵ期,后迅速退化至Ⅱ期。本实验没有观察到Ⅰ期性腺。云南盘鮈精巢发育也可分为5期。6-12月主要为Ⅱ期精巢,12月开始出现Ⅲ期精巢,以Ⅱ、Ⅲ期精巢过冬;次年1-3月主要为Ⅲ期精巢,含少量Ⅱ、Ⅳ期精巢,4月主要为Ⅳ、Ⅴ期精巢,5月全为Ⅴ期精巢,6月则以Ⅱ期精巢为主,含少量Ⅴ、Ⅵ期精巢。云南盘鮈卵巢成熟系数为1%～18%,精巢成熟系数为0.2%～8.0%;性腺成熟系数在4-6月出现一次高峰,成熟系数变化趋势与周年变化一致,说明云南盘鮈为一次产卵类型鱼类,且繁殖期集中在5月底至6月初。更多还原

【Abstract】 Discogobio yunnanensis is primarily distributed in the Daning, Yujiang, Nanpan and lower reaches of the Jinsha and Yagong Rivers. The dramatic decline of wild D. yunnanensis populations makes artificial breeding and culture research necessary. In this study, the annual cycle of gonad development of cultured D. yunnanensis adults was observed using anatomical and histological methods, aiming to provide basic data for artificial reproduction of D. yunnanensis. D. yunnanensis were collected from Daning River, with females averaging(17.04±4.18) g,(10.29±1.29) cm, 4-6 yr and males averaging(7.06±2.01) g,(7.44±0.89) cm and 3-6 yr. The test fish were maintained in a circulating water system with average conditions as follows: dissolved oxygen,(7.59±0.03) mg/L; pH,(7.98±0.79); water temperature,(17.5±1.5)℃ and a light to dark ratio of 14∶10. From June 2016 to June 2017, 5-8 male and female individuals were selected each mid-month for determination of biological parameters. The fish were dissected to observe gonad development and the gonadosomatic index(GSI) for each female and male was calculated based on measurements of gonad weight, length and width. Results demonstrate that D. yunnanensis can fully mature and reproduce under culture conditions. The ovary development of female D. yunnanensis adults were divided into five stages(stage Ⅵ) as stage Ⅰ was not observed in this study. Stage Ⅱ was the longest, lasting from June to November. Stage Ⅲ began in November and lasted to the following March. The ovary developed to stage Ⅳ in April and reached maturity in late May(stage Ⅴ). After ovulation, the ovary developed to stage Ⅵ for a short period and then rapidly degenerated to stage Ⅱ. Sperm development in male D. yunnanensis was also divided into five stages. Stage Ⅱ lasted from June to December, and stage Ⅲ began in late December. Sperm was at stage Ⅱ and Ⅲ during winter and, from January to March, the sperm was mainly at stage Ⅲ with a few individuals at stage Ⅱ or Ⅳ. The sperm developed to stage Ⅳ in early April, and gradually developed to stage Ⅴ in late April. May is the reproductive period for D. yunnanensis and the sperm of all males was at stage Ⅴ. In June, after the reproductive period, most sperm degenerated to stage Ⅱ with a small number at stage Ⅴ or Ⅵ. The GSI of ovaries differed from 1% to 18% and the GSI of testes ranged from 0.2% to 8.0%. The GSI of D. yunnanensis adults peaked from April to June, and the trend of GSI was consistent with the annual change of the gonad development, indicating that D. yunnanensis spawns once a year, and the breeding season is from late May to early June.更多还原