封闭循环水系统中养殖密度对大菱鲆生长和免疫的影响

Effect of stocking density on growth and immunity of Scophthalmus maximus reared in recirulating system

研究了大菱鲆幼鱼在封闭循环水系统中养殖密度对其摄食、生长、饲料利用率及免疫机能的影响。实验设计了4组不同处理,初始养殖密度分别为0.66 kg/m2、1.26 kg/m2、2.56 kg/m2、4.00 kg/m2,每个密度组设3个重复,为期100 d,实验结束时养殖密度分别为4.67 kg/m2、7.25 kg/m2、14.16 kg/m2、17.77 kg/m2。结果表明:大菱鲆生长速度与养殖密度呈负相关,各实验组的持定生长率(SGR)值分别为2.67、2.33、2.29、1.98;随着养殖密度的增加,各实验组大菱鲆的体重差异度出现显著变化(P<0.01);大菱鲆的饵料系数与养殖密度呈正相关,实验组1的饵料系数为0.70;实验组4的饵料系数为0.76;养殖密度对大菱鲆的免疫指标碱性磷酸酶(AKP)、酸性磷酸酶(ACP)及肝脏的脏器系数的影响不大。本实验结果可为鱼类循环水工厂化养殖管理提供参考。

Juvenile turbot（Scophthalmus maximus） were stocked and reared at four experiment densities for the study on the effect of stocking density on growth,feed coefficient and immunity.The initial densities were 0.66,1.26,2.56 and 4.00 kg/m2,respectively.The experiment lasted for 75 days with final stocking densities reached 4.67,7.25,14.16,17.77 kg/m2 respectively.It was found that,under the same experiment conditions,higher stocking densities have a negative effect on fish growth.The SGR（special growth rate） for the four treatments were 2.67,2.33,2.29 and 1.98,respectively.The uniformity of weight distributing within experiment groups decreased with increased density.However,the stocking density had positive effect on feed coefficient rate.Treatment 1 had the lowest feed coefficient rate of 0.70 and the highest coefficient was 0.76,found in treatment 4,the treatment with the highest density.It was also found that the stocking density had insignificant impact on liver organ index.This experiment will provide reference for land-based recirculation systems for fish culture.