摘要
对产卵前的雌鳗注射了不同剂量的甲状腺素(T4),然后利用放射性免疫法(RIA)测定了雌鳗血清、卵、胚胎及幼苗各发育时间段三碘甲腺原氨酸(T3)和甲状腺素(T4)的含量变化。结果发现,注射外源T424h后,随着雌鳗血清中的T4含量达到峰值,T3含量也达到了峰值。说明日本鳗鲡体内存在5’-单脱碘酶。与此同时,随着血清中T3和T4含量达到峰值,卵中的T3和T4含量也达到了峰值,进而证明母体中的T3和T4能够转入鳗鲡幼苗。进一步调整T4的注射剂量和时间后发现,在21℃水温条件下,T4的剂量为10～15mg·(500g)-1时,注射催产针前12h注射的效果最好。用该方法注射T4后,幼苗各发育时间段的存活率与对照组比较存在显著差异,出膜第9天的存活率由对照组的1.3%提高到22.0%。但日本鳗鲡幼苗最终未能存活,说明甲状腺素并不是影响日本鳗鲡幼苗存活的唯一因素。
The changes of triiodothyronine (T_3) and thyroxine (T_4) levels in serum, eggs and larvae were measured by radioimmunoassay (RIA) after T_4 injection in female Japanese eel spawners at doses of 5, 10, 15 and 20 mg ·(500g)-1 body weight fish. As results, T_3 level reached up to peak value following T_4 level up to peak value in maternal serum after 24 h of exogenous T_4 injection. Apparently, there was conversion of T_4 into T_3 in the broodstocks which suggests the presence of the enzyme, 5'-monodeiodinase, in Japanese eel. Meanwhile, along with the T_3 and T_4 levels in serum up to peak value, the T_3 and T_4 level in eggs also reached up to peak value. It further indicated that T_3 and T_4 in maternal circulation could be transferred into the oocytes and subsequently into the larvae. After readjusting the times and doses of T_4 injection, it was discovered that the most suitable doses of exogenous T_4 injection should be 10-15 mg·(500 g)-1 body weight and the optimal opportunity of T_4 injection should be 12 h before spawning under the condition of 21℃ water temperature. Compared with the control, the rate of larval survival in each stage of development tended to show remarkable increase (P<0.01) after spawners were treated with T_4. The rate of 9-day-old larval survival was elevated from 1.3% of control group to 22.0% of treated group. However, the larvae could not survive ultimately. It suggests that thyroid hormone may not be the only factor of affecting the larvae survival.
出处
《水产学报》
CAS
CSCD
北大核心
2005年第3期333-338,共6页
Journal of Fisheries of China
基金
中国水产科学研究院基金项目资助(2001-1-4)
关键词
日本鳗鲡
甲状腺激素
血清
卵
幼苗
Anguilla japonicas
thyroid hormone
serum
eggs
larvae
