饥饿对中华倒刺鲃仔鱼摄食、存活与生长发育的影响

The Effects of Starvation on Feeding,Survival,Growth and Development of Spinibarbus sinensis Larvae

在实验室条件下,通过饥饿试验,研究饥饿胁迫下中华倒刺鲃(Spinibarbus sinensis)仔鱼摄食、存活、生长发育的变化规律。结果表明:在(25±0.5)℃水温条件下,中华倒刺鲃仔鱼初次开口摄食的初次摄食率达86.7%,6～11日龄初次摄食率持续达100%,12日龄开始下降,18日龄进入PNR。延迟1～6d投饵对仔鱼成活率的影响不显著,之后,开始显著下降(P<0.05)。完全饥饿条件下,累计死亡率超过50%发生在19日龄,22日龄全部死亡。饥饿对仔鱼全长、头长、眼径、体高和尾柄高5项形态学生长指标的影响不同步,分别在延迟投饵时间达6,7,5,3,4d起显著低于正常投饵组(P<0.05)。饥饿仔鱼鳍发育停滞,饥饿达7d以上仔鱼除出现头大身瘦,脊索弯曲,肠道萎缩等饥饿仔鱼的一般形态特征外,还出现"胸角"现象。中华倒刺鲃仔鱼开始投饵的最适时间建议在6～8日龄。

Under the laboratory condition Spinibarbus sinensis larvae were reared at water temperature （25.0±0.5）℃ to examine the effects of starvation on the feeding,survival,growth and development under the starvation condition.The results showed that the larvae had the first feeding ability 5 days after hatching and the initial feeding rate was 86.7%,the unfed larvae had the highest feeding rate at 100% at the age of 6-11 days after hatching and followed by decreasing rate,and unfed larvae reached the point of no return（PNR）18 days after hatching.The survival rate was not affected when delayed initial feeding for 1-6 days,and then decreased with increasing of delay of initial feeding time（P〈0.05）.Under the absolutely hungry condition,the time of above 50% mortality and 100% mortality for the starvation larvae happened at the age of 19 days and 22 days after hatching respectively.When delayed initial feeding for 6,7,5,3,4 days,there were significant differences in growth rate of the total length,head length,eye diameter,body heigth and caudal peduncle height between treatments and controls respectively（P〈0.05）.The unfed larvae had bigger head and thinner body,curved spina dorsalis,atrophy of intestines etc,and also pectoral angle when starved for over 7 days,starvation prevented the development of all fins of the unfed larvae.Therefore,it is suggested that the most suitable first feeding time of Spinibarbus sinensis larvae should be within 6～8 days after hatching.