饲料中添加锌对星斑川鲽幼鱼生长、生理生化指标和机体抗氧化的影响

Effects of dietary zinc on growth,blood physiological and biochemical indices and antioxidant ability of juvenile starry flounder Platichthys stellatus

以酪蛋白和明胶为蛋白源,以七水硫酸锌为锌源,在基础饲料中分别添加锌0、50、100、150、200、400mg/kg,配制成6种等氮等能的精制饲料,饱食投喂初始体重为62.89±0.51g的星斑川鲽幼鱼66d,探讨饲料锌水平对星斑川鲽幼鱼生长、血液生理生化指标和机体抗氧化功能的影响。结果表明,添加150~400mg/kg饲料锌显著提高了星斑川鲽幼鱼的增重率（WGR）（P〈0.05）,且WGR的最大值及饲料系数（FCR）的最小值均出现在150mg/kg锌饲料组。添加100~200mg/kg饲料锌显著提高了试验鱼血液红细胞数量（P〈0.05）,0mg/kg锌饲料组的血细胞比容和血红蛋白含量均显著低于其他各组（P〈0.05）。血清蛋白含量不受饲料锌添加量的影响（P〉0.05）。血清溶菌酶（LSZ）活力随着锌添加量的增加而显著升高（P〈0.05）,在锌添加量为150mg/kg时达最高值;当添加量高于150mg/kg时,LSZ活力变化不显著（P〉0.05）。0与50mg/kg锌饲料组的血清铜锌-超氧化物歧化酶（CuZn-SOD）活力显著低于其他各组（P〈0.05）。0和50mg/kg锌饲料组肌肉丙二醛（MDA）含量显著高于其他各组（P〈0.05）,以150mg/kg锌饲料组最低（P〈0.05）。建议星斑川鲽幼鱼精制饲料中锌的适宜添加量为150mg/kg。

A study was conducted to investigate the effects of dietary zinc levels on growth,blood physiological and biochemical indices and antioxidant ability of juvenile starry flounder Platichthys stellatus.Basal diet was prepared using casein-gelatin as the protein source.Zinc（ZnSO4 ·7H2O） was added at graded levels（0,50,100,150,200,and 400 mg/kg diet） to basal diets to formulate six isonitrogenous and isoenergetic purified diets.Triplicate of six treatment groups of juvenile starry flounder（initial weight,62.89±0.51 g） were fed to apparent satiation for 66 d.The results showed that the weight gain rate（WGR） increased significantly when juvenile starry flounder were fed the diets with 150～400 mg/kg of dietary supplemental zinc（P0.05）.The highest WGR and the lowest feed conversion rate（FCR） were observed in treatments with 150 mg/kg of dietary supplemental zinc.The number of erythrocytes was significantly higher than the control group when the juveniles were fed the diets with 100～200 mg/kg of dietary supplemental zinc（P0.05）,and the hematocrit and hemoglobin of the control group fed basal diets without zinc were significantly lower than those of other groups with zinc treatment（P0.05）.Contents of serum protein in groups treated with all levels of zinc were comparatively similar（P0.05）.Activity of serum lysozyme（LSZ） in juvenile starry flounder increased significantly with the increasing level of dietary supplemental zinc（P0.05）,but no significant differences were observed among the juveniles fed the diets with equal to or higher than 150 mg/kg of dietary supplemental zinc（P0.05）.The LSZ activity peaked in the treatment with 150 mg/kg of dietary supplemental zinc.Activity of serum CuZn-superoxide dismutase（CuZn-SOD） in 0 and 50 mg/kg zinc treatment were significantly lower than those in other groups（P0.05）.The contents of malondialdehyde（MDA） in muscle of juveniles fed with 0 and 50 mg/kg zinc were significantly higher than those in other groups（P0.05）,while the minimum level of MDA was in 150 mg/kg zinc fed group.The optimal dose of dietary supplemental zinc in juvenile starry flounder purified diet was suggested to be 150 mg/kg.