延迟首次投喂对乌江中华倒刺鲃仔鱼补偿生长的影响

Effects of delayed initial feeding on compensatory growth of Spinibarbus sinensis larvae

为探明乌江中华倒刺鲃(Spinibarbus sinensis)仔鱼的最佳开口投喂时间,在实验室内对肠道贯通后的仔鱼进行了不同饥饿天数(1、3、5、7、9、11)的延迟首次投喂试验,探讨了仔鱼全长、体质量和特定生长率的变化。结果表明,仔鱼在饥饿条件下初次摄食率在饥饿第5天开始下降,即时病死率在饥饿第1天出现,初次摄食率随饥饿天数的延长而降低,而即时病死率增加。恢复投喂后,全长和体质量的增长值在5 d内与正常组无统计学意义差异(P>0.05),第7—11天差异具统计学意义(P<0.05)。全长的特定生长率仅在饥饿9 d和11 d后投喂的恢复值与正常组存在统计学意义差异(P<0.05),而体质量的特定生长率在所有饥饿天数下投喂的恢复值与正常组都存在统计学意义差异(P<0.05)。结合上述结果,建议乌江中华倒刺鲃仔鱼首次投喂的最佳时间在肠道贯通时。

In order to find out the optimum time of first feeding of Sinopectus sinensis larvae in Wujiang River, a delayed initial feeding experiment of different starvation days (1, 3, 5, 7, 9, 11) after the intestinal tract opened in the laboratory was conducted, and the changes of total length, body weight and specific growth rate were discussed. The results showed that the first ingestion rate of larvae under starvation began to decrease on the fifth day, and the immediate mortality rate appeared on the first day. The first ingestion rate decreased with the prolongation of starvation days, while immediate mortality rate increased with time. After resuming feeding, there was no significant difference of total length increments and body weight increments between the starvation group and normal group within 5 days (P>0.05), but changed after 7 to 11 days (P<0.05). The recovery value of specific growth rate of total length was significantly different only from the feeding after 9 and 11 days of starvation and the normal group (P<0.05), but the value of body weight of all the starvation groups were significantly different from normal group (P<0.05). Based on the above results, it is suggested that the best time of first feeding of Sinopectus sinensis larvae should be the time when intestinal tract opened.