养殖密度对流水池塘系统中俄罗斯鲟幼鱼代谢机能的影响

摘要

为研究流水养殖系统中不同放养密度对俄罗斯鲟Acipenser gueldenstaedti幼鱼血液激素、 生理生化组分的影响机制,选取初始体质量为(29.70±1.32)g的俄罗斯鲟幼鱼,分别按2.5 kg/m3(80 ind./m2)(SD1组)、3.6 kg/m3(115 ind./m2)(SD2组)和4.7 kg/m3(150 ind./m2)(SD3组)3个养殖密度进行流水池塘(4.4 m×4.4 m×0.6 m)养殖,每个密度设3个重复,试验周期为90 d.结果表明:俄罗斯鲟幼鱼养殖50 d后,各密度组试验鱼皮质醇含量迅速升高,至90 d时,SD3密度组皮质醇含量显著高于SD1、SD2密度组;高养殖密度对俄罗斯鲟幼鱼血液生理生化指标均产生一定的抑制作用,血红蛋白含量与养殖密度呈显著正相关(P<0.05);不同养殖密度中俄罗斯鲟幼鱼的白细胞含量有显著性差异(P<0.05),SD3组血液中白细胞数量较SD1、SD2组大幅增多,表明长期高密度养殖对俄罗斯鲟幼鱼免疫机能产生一定影响;各密度组血糖含量均呈现出先上升后下降的趋势,最终SD1组血糖含量显著低于SD2、SD3组(P<0.05);各密度组总胆固醇和总蛋白含量无显著性差异(P>0.05);试验结束时,SD3组血液甘油三酯含量显著高于SD1、SD2组(P<0.05),且SD1和SD2组间无显著性差异(P>0.05).研究表明:在养殖密度达到12.12 kg/m3时,俄罗斯鲟幼鱼皮质醇含量急剧增加,加速幼鱼糖异生作用,耗能增加,试验鱼生长明显受到抑制;俄罗斯鲟幼鱼能量利用顺序依次为血糖>血清蛋白>血脂.%Juvenile Russian sturgeon Acipenser gueldenstaedti with initial body weight of 29 . 70 g ± 1 . 32 g were reared in nine square concrete ponds(4. 4 m×4. 4 m×0. 6 m) at stocking density of 2. 5 kg/m3(80 ind. /m2) (SD1), 3. 6 kg/m3(115 ind. /m2)(SD2), and 4. 7 kg/m3(150 ind. /m2)(SD3) for 90 days with triplication to investigate the influence of stocking density on hormone, physiological and biochemical components of the juvenile. Cortisol levels were shown to be elevated in the Russian sturgeon reared for 50 d in the experimental groups, signifi-cantly higher in the fish reared for 90 d in group SD3 than in SD1 group and SD2 group(P<0. 05). The hemoglo-bin content was found to be significantly and positively correlated with the stocking density(P<0. 05). There were significant differences in leukocyte contents at different stocking densities of Russian sturgeon ( P<0 . 05 ) , signifi-cantly higher white blood cell count in the juvenile Russian sturgeon in group SD3 than those in group SD1 and group SD2 ( P<0 . 05 ) , indicating that the long-term high-density culture of the Russian sturgeon led to physical and pathological damage of the fish by the end of the experiment. The Russian sturgeon juveniles showed a tenden-cy of blood-sugar levels upgrade first then descending, significantly lower in group SD1 than in group SD3 and group SD2 ( P<0 . 05 ) . There were no significant differences in levels of total cholesterol and total protein ( P>0. 05). At the end of the experiment, the juveniles had significantly higher blood triglyceride content in group SD3 than the juveniles in group SD1 did ( P<0 . 05 ) , without significant difference between group SD1 and SD2 . The findings indicate that the order of energy utilization in Russian sturgeon was expressed as blood sugar >serum pro-tein > blood lipid.