饥饿胁迫对曼氏无针乌贼幼体的影响

Impacts of starvation on biochemical indices and behaviors of Sepiella maindroni juveniles

以曼氏无针乌贼(Sepiella maindroni)初孵幼体为材料,分析了饥饿胁迫对幼体存活、行为变化,消化酶活力,脂肪酸组成,以及饥饿后再投喂对幼体生长及成活率的影响。结果表明:饥饿对曼氏无针乌贼幼体存活、体态和游动行为的影响较大,至第7天全部死亡。初孵幼体的胃蛋白酶活力在饥饿5d时出现最低值0.23±0.04U·mg-1·prot-1;胰蛋白酶活力在饥饿5d时最高为737.30±26.26U·mg-1·prot-1;淀粉酶活力在饥饿5d时降至最低13.93±2.00U·g-1·prot-1;脂肪酶活力在饥饿2d时最低17.46±0.79U·g-1·prot-1。饥饿状态下,机体消耗利用自身脂肪酸成分的顺序依次为:饱和脂肪酸,单不饱和脂肪酸,多不饱和脂肪酸中的低不饱和脂肪酸,最后是高不饱和脂肪酸。曼氏无针乌贼的不可逆点(PNR)为第5天。实验结果有助于合理制定曼氏无针乌贼育苗前期饵料的投喂策略。

Taking the newly hatched Sepiella maindroni juveniles at test materials,this paper studied the impacts of starvation on the survival rate,behaviors,digestive enzyme activities,and fatty acid composition,and the effects of re-feeding after starvation on the survival rate and growth of the juveniles.With the increasing duration of starvation,the survival rate,body shape,and behaviors deteriorated significantly,and died completely on the 7th day of starvation.The pepsin activity decreased to the minimum（0.23±0.04 U·mg-1·prot-1） whereas the trypsin activity increased to the maximum（737.30±26.26 U·mg-1·prot-1） on the 5th day of starvation,and the amylase activity and lipase activity decreased to the minimum（13.93±2.00 U·g-1·prot-1 and 17.46±0.79 U·g-1·prot-1） on the 5th day and 2nd day,respectively.Under starvation,the consumed fatty acids in the juveniles themselves were in sequence saturated fatty acid,monounsaturated fatty acid,low chain unsaturated fatty acids in poly unsaturated fatty acid,and highly unsaturated fatty acid.The point of no-return of the juveniles was the 5th day of starvation.These results could be helpful to the rational formulation of the feeding strategies for S.maindroni cultivation.