真鲷仔稚鱼鳔发育与分化研究

Differentiation and Development of the Swimbladder Structure in Larvae of the Red Sea Bream Pagrus major

采用组织切片和显微观察方法，对孵化后１～３０ｄ的真鲷（Ｐａｇｒｕｓｍａｊｏｒ）仔稚鱼鳔的发育与分化发育进行了研究。结果表明：孵化后１～２ｄ的仔鱼，开始在消化道的前端背部出现鳔原基，接着出现导气管、鳔腔、气腺和迷网，而后鳔囊开始充气。到孵化后２０～３０ｄ，鱼鳔分化发育基本稳定。真鲷仔鱼鳔器官的分化发育早期大致可以分为两个阶段：一是鳔腔扩大阶段，约在仔鱼孵化后的３～４ｄ，此阶段的发育是非功能性的；二是鳔囊充气阶段，大约在孵化后９～１０ｄ左右出现，形成一个缓慢向前方伸展的椭圆形鳔囊，此阶段鳔的发育是功能性的。此时鳔器官的发育好坏对真鲷仔鱼的生理、生态影响很大，反映在成活率的高低方面显得非常明显。真鲷鳔器官的分化发育在仔稚鱼期基本完成。

The larvae of the red sea bream differentiate their swimbladder 1-30 days after hatching. There are some changes during this time. It is first observed that a germinal swimbladder protrudes upward from the digestive tube dorsal wall 1-2 days after hatching. Then the swimbladder cavity appears and becomes larger and longer. In the meanwhile, gas glands and rete mirabile are formed, the larvae bear gas in their swimbladder, and the peneumatic duct is present. In 20-30 days the swimbladder becomes stable. The red sea bream complete the differentiation of their swimbladder in their larval stage. It is divided into two stages. One is unfunctional, during which the swimbladder cavity becomes larger and larger. The second stage is functional, during which the larvae bear gas in their swimbladder. The differentiation and development of the swimbladder is completed at the larval stage.