延迟投饵对高体革鯻仔鱼早期生长发育的影响

Effects of delayed initial feeding on growth and development in jade perch Scortum barcoo larvae

在水温为24．5—27．8℃条件下，通过延迟投饵对高体革鯻Scortum barcoo仔鱼的摄食、存活及生长等进行了研究。结果表明：宝石鲈仔鱼的卵黄囊在4日龄时吸收完毕，仔鱼进入混合营养期；仔鱼的油球在6日龄时吸收完毕，仔鱼进入外源性营养期。宝石鲈仔鱼在3日龄时开口摄食，投饵后2h内仔鱼的初次摄食率达到97％；仔鱼在延迟投饵1、2、3、4、5d时，投饵后2h内的初次摄食率分别为100％、90％、67％、30％、0。宝石鲈仔鱼的“不可逆点”（PNR）出现在仔鱼开口摄食后的第4d（7日龄）。延迟1—2d投饵，9日龄时仔鱼的存活率在85％以上；延迟3d投饵时，其存活率为60％；延迟4d投饵时，其存活率仅为22．5％；完全饥饿条件下，宝石鲈仔鱼9日龄时全部死亡。在保证索饵周期相同的情况下，延迟投饵在0—3d内，各试验组之间的仔鱼在全长及体长上没有显著差异（P〉0．05）；而延迟4d投饵试验组的仔鱼与延迟0—3d投饵试验组的仔鱼在全长、体长上存在显著性差异（P〈0．05）。宝石鲈的最佳投喂时间是在仔鱼开口后的3d之内。

The effects of delayed initial feeding on food consumption, survival and growth were studied in jade perch Scortum barcoo larvae. The larvae exhausted the yolk at age of 4 days, then entered the period of mixed nutrition at water temperature of 24.5 - 27.8 ℃. The oil globules were absorbed completely in 6 day larvae which entered the exogenous nutrition. The larvae began feeding at the age of 3 days, with initial feeding rate of 97% two hours after feeding. However, the initial feeding rate was 100% , 90% , 67% , 30% and 0% two hours after feeding when the initial feeding was retarded 1 day,2 days,3 days, 4 days and 5 days, respectively. The point of no return （PNR） occurred 4 days after feeding. The 9 day old larvae had survival rate of 85%, 60%, 22. 5% and 0% （death） when their initial feeding was retarded 1 or 2 days, 3 days, and 4 days, respectively. At the same feeding peri gin the there was no significant difference in total body length and body length when the larvae were retarded to befeeding between the 3 day delayed initial feeding group and the control group, but significant difference between 4 and 5 day delayed initial feeding groups and the control group, indicating that the optimum initial feeding time was within 3 days after the larvae opened mouth.