大西洋牙鲆冷冻精子×褐牙鲆卵杂交胚胎的发育及胚后发育

Embryonic and postembryonic development of hybrid produced with frozen sperms of Paralichthys dentatus and eggs of Paralichthys olivaceus

利用大西洋牙鲆冷冻精子与褐牙鲆卵授精，培育出了生长健康的杂交鱼苗。并对杂交后代的胚胎发育、胚后发育和不同温度下的生长特征进行了研究。利用OLIMPUS显微镜连续观察和描述了冷冻精子受精杂交胚胎的发育，在水温15～17．1℃，其受精卵经过卵裂、囊胚、原肠胚、胚孔封闭、肌节胚、尾芽胚、心跳胚、出膜胚等时期的发育，经历65h57min完成胚胎发育进入胚后发育，发现胚胎搐动15min后心脏开始跳动。利用OLIMPUS解剖镜每天观察和记录一次鱼苗的生长形态，并测定其体全长；将杂交鱼苗的胚后发育划分为卵黄囊吸收期（出膜后1-6d）、变态前期（出膜后7～25d）、变态期（出膜后25～30d）和变态后生长期（出膜30d以后）4个时期。对16～17℃、18～19℃、20℃和22～23℃4个温度环境下胚胎发育的研究结果显示，杂交胚胎宜于在16～20℃的水温下发育，鱼苗在22～23℃孵化出膜后2～3d大量死亡。对18—19℃、20℃、22℃和24℃4个温度下稚鱼的生长研究结果显示，变态期稚鱼在22—24℃水温下饲养时变态和生长速度较18-20℃快。

In order to study hybrid offspring＇ s embryonic development, postembryonic development and growth characteristics under different temperatures, crossing test was carried out using frozen sperms of summer flounder（ Paralichthys dentatus ） and eggs of Japanese flounder（ Paralichthys olivaceus ）. The development of the hybrid embryos was successively observed and described under Olympus microscope. After 65 hours and 57 minutes the embryonic development finished, which contains cleavage stage, blastula stage, gastrula stage, closure stage of blastopore, somites stage, tail bud stage, heart-beating stage, and hatching stage. Then the embryos began postembryonic development. During the embryonic development the heart began to beat at 15 minutes after the embryos moved. Morphological characters and growth of the fries were also observed by Olympus dissecting microscope and recorded once every day. According to these, the postembryonic development was divided into four stages： yolk-sac absorption stage （ 1 - 6 days after hatching）, premetamorphosis stage （ 7 - 25 days after hatching）, metamorphosis stage （ 25 - 30 days after hatching） and growth stage after metamorphosis. The embryonic development at 16- 17 ℃,18- 19 ℃,20 ℃ and 22- 23 ℃ was studied. Result showed that the hybrid embryos developed better at 16- 20 ℃, and a great deal of the fries hatched at 22 - 23 ℃ died 2 - 3 days after hatching. Growth of the postlarva at 18 - 19 ℃, 20 ~（2, 22 ℃ and 24 ℃ was also studied, result showed that the metamorphosis and the growth rate of metamorphosis stage postlarva were higher at 22- 24 ℃ than that at 18- 20 ℃.