银鲴性腺发育和胚胎发育的观察

OBSERVATION ON THE GONADAL DEVELOPMENT AND EMBRYONIC DEVELOPMENT OF XENOCYPRIS ARGENTEA GUNTHER

  • 摘要: 生长在湖南江河、池塘、水库环境的银鲴,性成熟年龄一般是二冬龄(2+),雄性比雌性提前一年成熟。江河银鲴每到生殖季节,可以自行产卵、受精,繁衍后代;池养银鲴却不能自然产卵,其卵母细胞只能发育到初级卵母细胞阶段(Ⅳ时相),必须通过人工催情,才使卵母细咆由第Ⅳ时相发育到第Ⅴ时相。池养雄性银鲴,能够完成由精原细胞到精子的全部发育过程。冬季,达性成熟的银鲴,雌性卵巢为Ⅲ期,雄性精巢为Ⅳ期。每年的3月份,银鲴开始进入性成熟期,4月份为它的生殖盛期。银鲴是鲴亚科中产半浮性卵的鱼类。银鲴在胚胎发育早期行盘状卵裂。当水温21—23℃时,其胚胎发育历经26小时10分,胚胎发育总热量为550—602度时;银鲴从受精卵到仔鱼期结束(鱼苗下池),整个过程历时112小时,区分胚胎发育、仔鱼发育两个阶段。胚胎发育又划为5个时期。

     

    Abstract: In Hunan, the age at first sex maturity of Xenocypris argentca Gunther which grows in the environment of Xiangjiang river, pond and reservoir is 2 years; the male spawners ripen 1 year earlier than the female generally. During the breeding season. Xenocypris argentca of the Xiangjiang river begin their sexual activities-di.splaying of estrus, such as ovulation and discharging milt. In the environment of a pond, it, is impossible for the pond-cultured Xenocypris argentca to propagate naturally because of the shortage of certain ecological conditions. The oocytes of the pond-cultured Xenoeypris argentca can only develop to the period of primary oocytes (phase Ⅳ), hence it is very necessary to induce maturation division artificially so that meiosis can take place and the oocytes can develop from phase Ⅳ to phase Ⅴ. The entire course of spermatogenesis,from spermatogonium to spermatozoon, can be completed endogenously in the pond environment.Duing the winter, the testes of those fish which reach sex maturity develop to stage Ⅳ; the ovaries develop to stage Ⅲ. Induced spawing has been successfully carried out from mid-April until early-May, with the water,temperature from 20℃ to 22℃.The matured egg of Xenocypris argcntea is spherical in shape, and semi-pelagic.The embryonic development of Xenocypris argentca is as follows: When the water temperature is 21—23℃, the duration of incubation from fertilized egg to the larva breaking off from the membrane lasts about 26 hours. It takes 112 hours for the fertilized egg to grow into a larva. The embryonic development of Xenocypris argentea can be divided into 5 stages: fertilized egg stage, cleavage-blastula stage, gastrula stage, organogenesis stage and hatching.

     

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