用4种不同浓度的甲状腺素(T4)分别浸泡斜带石斑鱼卵黄囊期仔鱼,研究T4对仔鱼发育、生长和存活的影响.结果表明,在孵化后24h内,T4对仔鱼发育的促进作用不明显;在孵化24h后,T4对仔鱼消化道的发育有促进作用.在孵化后72h,0.01 mg·L-1 T4处理组仔鱼小肠管径、直肠管径、全长与对照组相比差异均不明显;0.10 mg·L-1和1.00 mg·L-1 T4处理组仔鱼小肠和直肠管径显著比对照组大(P＜0.01),1.00mg·L-1 T4处理组仔鱼全长显著比对照组短(P＜0.01),而0.10 mg·L-1处理组仔鱼全长与对照组相比无明显差异(P＞0.05).在孵化后第8天,0.10 mg·L-1 T4处理组仔鱼存活率明显比对照组高(P＜0.01),而0.01 mg·L-1 T4组和1.00mg·L-l T4组与对照组之间存活率差异不明显(P＞0.05).结果提示0.10mg.L-1 T4处理能促进斜带石斑鱼卵黄囊期仔鱼的消化道发育并提高其存活率.%The effect of four doses of thyroxine (T4) on orange-spotted grouper (Epinephelus coioides)yolk-sac larvae was studied. The effect of T4 on larval development was not obvious within 24 hourspost-hatching (hph). However, the advancement in development of gut was induced by T4 treatmentafter 24 hph. The differences between the control and 0.01 mg · L-1 T4 groups were not observed at 72hph. Compared with the control, the diameter of larval intestine and rectum in both 0.10 mg · L-1 and1.00 mg · L-1 T4 groups were obviously longer at 72 hph（P ＜ 0.01）, however, the larval total length in1.00 mg · L-1 T4 groups was obviously shorter（P ＜ 0.01）, while the larval total length were notsignificantly affected by 0.10 mg · L-1 T4 treatment（P ＞ 0.05）. The rate of survival in 0.10 mg · L-1 T4groups was obviously higher than that in the control by 8 days post-hatching（P ＜ 0.01）, while that ineither 0.01 mg · L-1 groups or 1.00 mg · L-1 T4 groups was not（P ＞ 0.05）. The results indicated that 0.10mg · L-1 T4 treatment could promote Epinephelus coioides alimentary development and improve therate of survival.
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