哲罗鱼(♀)与细鳞鱼(♂)杂交种胚胎及仔稚鱼发育

Embryonic,larval and juvenile development of hybrid between Hucho taimen(♀)×Brachymystax lenok(♂)

通过性激素药物诱导和人工繁育技术对哲罗鱼(♀)(Hucho taimen)与细鳞鱼(♂)(Brachymystax lenok)进行属间远缘杂交,并对杂交种胚胎及仔稚鱼的发育进行初步研究。结果表明:在水温6.2～8.9℃条件下,哲罗鱼(♀)×细鳞鱼(♂)的杂交受精卵完成胚胎期发育所需的有效积温为5806.70℃·h,整个胚胎发育过程可分为6个阶段,24个发育分期。刚破膜的仔鱼不具有游泳能力,全身透明,体循环清晰可见;7d后卵黄囊期仔鱼口裂明显,头顶部和腹部开始变得浅黄,尾鳍分化不断完成;17d后,仔鱼开始上浮,卵黄囊基本吸收完全,仔鱼具有游泳能力,鳍条和腹部鳞片开始不断分化。上浮40d后仔鱼发育成稚鱼,脂鳍分化和身体两侧鳞片覆盖基本完毕,幼鲑斑开始出现。根据研究结果可以初步断定,该杂交种的胚胎发育速度介于双亲之间,稚鱼期基本具备成鱼形态特征,早期杂交种外部形态略偏向于哲罗鱼,但仔稚鱼期生长较双亲快,推断这种杂交优势的贡献力可能来源于母本。

In the present study,intergeneric hybridization between Hucho taimen（ ♀） and Brachymystax lenok（ ♂） were carried out by hormone induction and artifical propagation. The embryonic,larval and juvenile development of the hybrid were also studied preliminarily. The results showed that the total effective accumulated temperature of the embryonic development of the hybrid between Hucho taimen（ ♀） and Brachymystax lenok（ ♂） was 5 806.70℃·h at 6.2-8.9℃ .The embryonic development were divided into 6 stages（prophase of cell division,cell division stage, blastula stage,gastrula stage,neurula stage and organ formation stage）,24 periods. The hatching larvae could not swim,of which the bodies were diaphanous,and systemic circulation was clear. Seven days later,mouth cleft of yolk sac larva was clear,of which the top of head and belly began to be buff,and caudal fin differentiated unceasingly. After 17 days,larva could swim,of which the yolk sac was absorbed completely,fin and scale began to differentiate uninterruptedly. After floating 40 days,the larvae developed in to juveniles with adipose fin differentiated and scales in both sides covered,of which parr marks began to appear.It may be considered that embryonic development speed of the hybrids was between their parents.Juvenile characters were similar to their parents,too. Morphological characteristics in the early stage of the hybrids was more similar to Hucho taimen,which grew much faster than their parents. It can be concluded that the contribution to hybridization advantage may come from maternal parent.