倒刺鲃仔鱼饥饿耐力的研究

在水温为（27.0±0.5）℃条件下,通过饥饿试验,观察了饥饿对倒刺鲃Spinibarbus denticulatus仔鱼摄食、生长与形态变化和存活的影响,研究饥饿胁迫下倒刺鲃仔鱼的饥饿耐力。结果表明：倒刺鲃5日龄仔鱼初次开口的摄食率达90%,6-11日龄仔鱼的初次摄食率持续达100%,12日龄开始下降,17日龄进入饥饿不可逆点（PNR）;延迟1-8 d投喂对仔鱼存活的影响不显著,之后,仔鱼的成活率随延迟投喂天数的增加而显著降低,饥饿仔鱼超过50%死亡率发生在PNR前1 d;完全饥饿条件下,饥饿0-7 d内,仔鱼全长为正增长,之后,全长开始转为负增长,饥饿仔鱼鳍褶消失速度减缓,臀鳍芽发育停滞,腹鳍芽未能形成,在接近或处在PNR期时,仔鱼的形态发生显著变化,出现脊索弯曲、头大身瘦、肠道萎缩、胆囊膨大且里面充满黄绿色胆汁以及＂胸角＂等现象。从形态上的变化可对倒刺鲃仔鱼的营养水平作出初步判断。倒刺鲃仔鱼的补偿生长能力和耐饥饿能力较强。

The starvation endurance of Spinibarbus denticulatus larvae

The starvation endurance and effects of starvation on feeding ability,growth,morphological change,and survival in larval Spinibarbus denticulatus were studied in a laboratory at water temperature of（27.0±0.5）℃.The results showed that the larvae had initial feeding ability 5 days after hatching,with initial feeding rate of 90%.The unfed larvae had the maximal feeding rate of 100% 6-11 days after hatching,following by decreasing rate.The point of no return（PNR）was observed in the unfed larvae 17 days after hatching.The survival rate was not affected significantly by delayed initial feeding for 1-8 days,and then decreased significantly with increase in delayed initial feeding time.Above 50% of mortality occurred in the unfed larvae 1 day before PNR.Under the absolutely hungry condition,the larvae had growth in total length when delayed initial feeding for 1-7 days and subsequently degrowth,and undevelopment of anal fin and ventral fin appeared.The unfed larvae had curved spina dorsalis,big head and thin body,atrophic intestines,big gall bladder,and yellow and green bile in the gall bladder before or in PNR stage.According to the changes in morphology of the larvae,it is suggested that the larvae have strong capability of compensatory growth and starvation endurance.