白甲鱼(Onychostoma sima)早期阶段生长与发育的研究(英文)

Study on Growth and Development of Early Postembryonic Stage of Onychostoma sima

[目的]研究白甲鱼(Onychostoma sima)早期发育阶段的生长与发育情况。[方法]采用人工催产、人工授精的方法获得受精卵,并在实验室条件下进行孵化,测定体质量、体长、肛前长和体高等指标建立仔鱼生长模型。[结果]水温在(20±1.5)℃时,初孵仔鱼的全长和体质量分别是(10.28±0.05)和(7.79±0.08)mg。白甲鱼仔鱼在孵化后第4天开始摄食,初次摄食率为48%,第6天初次摄食比率达到100%。饥饿不可逆点(PNR)的时间为13.5d。本研究中还观察到白甲鱼仔鱼PNR点的出现时间与完全饥饿组死亡时间相隔只有2d,说明白甲鱼仔鱼一旦到达生长的不可逆点,将会在短期内迅速面临死亡,因此在此阶段须满足白甲鱼仔鱼各种生长条件,保证各个器官都得到充分发育,减少早期因环境不利而造成的死亡或生长停滞现象。[结论]该研究为解决人工养殖中出现的问题提供理论依据。

[Objective] The paper was to study the growth and development of Onychostoma sima in postembryonic development stage. [Method] The oosperm was obtained by artificial spawning and artificial insemination method, and hatched under laboratory condition. The indexes such as body weight, body length, length in front of anus and body height were measured to establish larvae growth model. [Result] When the water temperature was （20±1.5） ℃, the body length and body weight of newly hatched larvae were （10.28±0.05） mm and （7.79±0.08） mg, respectively. O. sima larvae begin to feed on the 4 th day after hatching, the initial feeding rate was 48%, the highest feeding rate was 100% on the 6 th d. The-point-of-no-return （PNR） was 13.5 d. In addition, it was also observed that the appearance time of PNR point of O. sima larvae was close to death time of completely starved group, being only 2 d, indicating that once O. sima larvae reached the PNR point, they would face death threats within short time. Therefore, various growth conditions for O. sima larvae should be satisfied to ensure full development of all organs, thereby reducing death and growth stagnation caused by adverse environment in early postembryonic stage. [Conclusion] The study provided theoretical basis for solving the problems in artificial breeding.