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

中文关键词: 星斑川鲽  锌  生长  生理生化指标  抗氧化

英文关键词: Platichthys stellatus  Zinc  Growth  Physiological and biochemical indices  Antioxidation

中文摘要:

      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。

英文摘要:

      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 (P<0.05).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 (P<0.05),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 (P<0.05).Contents of serum protein in groups treated with all levels of zinc were comparatively similar (P>0.05).Activity of serum lysozyme (LSZ) in juvenile starry flounder increased significantly with the increasing level of dietary supplemental zinc (P<0.05),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 (P>0.05).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 (P<0.05).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 (P<0.05),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.