异育银鲫经过低温下停食后的补偿生长

Compensatory growth of gibel carp,Carassius auratus gibelio,following food deprivation under low temperature

在室内水槽中进行了10周实验，以检验异育银鲫（Carassius auratus gibeti）经过低温下停食后的补偿生长。实验鱼初始体质量为（5．1±0．1）g，分为4组：2组鱼在第1～4周内被停食，在第5～10周分别恢复投喂蛋白能量比为23g·MJ^-1（SL组）和26g·MJ^-1（SH组）的等能饲料；另2组鱼（CL组和CH组）在1～4周内投喂蛋白能量比为23g·MJ^-1的饲料，在第5～10周分别投喂蛋白能量比为23g·MJ^-1（CL组）和26g·MJ^-1（CH组）的饲料。第1～4周内水温控制在14．8～15．2℃，第5～10周内水温控制在24．8～25．2℃。结果表明，第4周结束时SL组和SH组体质量明显低于CL组和CH组；SL组和SH组全鱼水分、蛋白质和灰分百分含量明显高于CL组和CH组，但脂肪含量明显低于后者。恢复投喂期间，SL组在第7～10周内SGR高于CL组，SH组第5～8周内SGR高于CH组，但SL组与SH组，CL组与CH组之间SGR无显著差异（P〉0．05）。实验结束时，SL组和SH组的体质量分别低于CL组和CH组，SL组与SH组间及CL组与CH组间体质量无显著差异（P〉0．05）；SL组和SH组全鱼、躯干和内脏团内蛋白质和灰分含量分别高于CL组和CH组，脂肪含量分别低于CL组和CH组。本实验结果显示，经过低温下停食后，异育银鲫仅表现出部分补偿生长能力，恢复投喂期间增加饲料蛋白质含量未明显增强异育银鲫的补偿生长。

A 10-week experiment was carried out to evaluate the compensatory growth of gibel carp（ Carassius auratus gibelio ） following feed deprivation under low temperature. The initial body weight of the fish were （5.1 ± 0.1 ） g. Four feeding treatments were established. Two groups of fish were deprived of diets during weeks 1 to 4, and re-fed with two isocaloric diets,either a low-protein diet（LP diet） with ratio of protein to energy（P/E） of 23 g·MJ^-1（SL group） or a high-protein diet（HP diet） with P/E of 26 g·MJ^-1 （SH group） ,in excess during weeks 5 to 10,while two other groups were fed LP diet during weeks 1 to 4, and fed LP diet（CL group） or HP diet（CH group） during weeks 5 to 10. In the experiment, water temperature was controlled at 14.8 - 15.2 ℃ during weeks 1 to 4,and at 24.8-25.2℃ during weeks 5 to 10.At the end of week 4, the body weight was lower in SL and SH treatments than in CL and CH treatments. Moisture; protein and ash contents in whole body were higher, while whole body lipid content was lower in SL and SH treatments than those in CL and CH treatments. Specific growth rate（SGR） was higher in SL than that in CL during weeks 7 to 10, and SGR was higher in SH than that in CH during weeks 5 to 8. At the end of the experiment, the fish in SL and SH treatments had lower body weight than that normally fed fish（SL versus CL,SH versus CH）. Protein and ash contents in whole body,carcass and viscera were higher in SL and SH treatments than those in normally fed treatments. During weeks 5 to 10, there were no significant differences（ P 〉0.05） in SGR, body weight and proximate composition in whole body, carcass and viscera between the treatments of SL and SH, and between the treatments of CL and CH. The results of the present study suggest gibel carp deprived of food under 14.8 - 15.2 ℃ and re-fed under 24.8 - 25.2 ℃ show partial growth compensation, and increasing dietary protein level has no significantly positive effect on enhancing intensity of compensatory growth.