大鳍鳠胚胎及仔稚鱼发育观察

Morphological development of embryos and larvae of Mystus macropterus

  • 摘要: 大鳍鳠 (Mystus macropterus) 是一种亟待开发的优质养殖品种。探明养殖大鳍鳠早期发育阶段的特征和规律,可为其人工催产和苗种培育提供理论依据。采用显微镜观察法,对其胚胎及仔稚鱼发育各时期的形态特征和发育特点进行了研究,并对其形态学指标进行了测量,推算出仔稚鱼阶段生长特性的回归方程。结果表明:大鳍鳠受精卵呈椭圆形、黄褐色,卵径为 (3.46±0.3) mm;平均水温26.2 ℃下,大鳍鳠胚胎发育历时79 h,积温为2065.26 h·℃,根据发育时胚胎的典型外部形态特征,将其分为受精卵、胚盘期、卵裂期、囊胚期、原肠期、神经胚期、器官分化期和出膜期共8个阶段28个时期;初孵仔鱼全长 (7.31±0.52) mm,仔鱼期历时10 d,仔鱼前期卵黄囊大部分被吸收,全长特定生长率 (SGRL) 为9.79%,体质量特定生长率 (SGRm) 为12.31%,出膜后7~8 d仔鱼大部分开口,9 d卵黄囊消失,仔鱼后期SGRL为4.15%,SGRm为12.25%。稚鱼期历时11 d,各鳍基本长成,体型和体色接近成鱼,SGRL为4.30%,SGRm为13.17%,全长22~24 mm。统计模型显示,大鳍鳠仔稚鱼的生长属于异速生长类型。

     

    Abstract: Mystus macropterus is a high-quality aquaculture variety that urgently needs to be developed. Exploring the characteristics and patterns of early developmental stages of cultured M. macropterus can provide basic data for its seedling cultivation and large-scale efficient seed production. We studied the morphological characteristics and developmental features of its embryos and juveniles by microscopic observation, and measured the morphological indicators to derive regression equations for the growth characteristics of juveniles. The results show that the fertilized eggs of the fish were oval and yellowish brown, with a diameter of (3.46±0.3) mm. At incubation temperature of 26.2  ℃, the embryos took 79 h to develop for eight stages with 28 periods, including fertilization, cleavage, blastocyst, gastrula, neuroembryo, organ differentiation and hatching, and the total accumulative temperature was 2065.26 h·℃. The total length of the larvae was (7.31±0.52) mm, the larvae stage lasted for 10 d, and most of the yolk sac was absorbed at early stage of larvae. The full-length specific growth rate (SGRL) was 9.79%, and the weight-specific growth rate (SGRm) was 12.31%. Most of the larvae opened 7–8 d after membrane emergence, and the yolk sac disappeared on 9th day. The SGRL and SGRm were 4.15% and 12.25% at later stage of larvae, respectively. The juvenile stage lasted for 11 d. The fins were basically mature, and the body size and body color were close to those of adult fish. SGRL was 4.30%, SGRm was 13.17%, and the total length was 22–24 mm. The statistical model shows that the growth of the larvae and juveniles is of allometric type.

     

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