斜带石斑鱼幼鱼对羟基蛋氨酸铜的需求

在斜带石斑鱼(Epinephelus coioides)幼鱼基础饲料(铜质量分数2.03 mg/kg)中分别添加6个水平的羟基蛋氨酸螯合铜(hydroxy methionine copper,HMC),制成铜质量分数分别为2.03、4.04、6.20、10.67、13.96 mg/kg的实验饲料,饲喂6周后,探讨HMC对幼鱼生长、非特异性免疫酶活性和组织铜沉积的影响,确定幼鱼饲料中铜的最适需要量。结果表明,饲料中添加HMC,对石斑鱼的增重率、特定生长率(SGR)和饲料系数等生长性能的影响有统计学意义(P0.05),以铜质量分数6.20 mg/kg组增重率和特定生长率最高,饲料系数最低,高于或低于2.03和13.96 mg/kg组,差异有统计学意义(P0.05),与4.04和10.67 mg/kg组差异无统计学意义(P0.05);但对成活率、肝体比影响差异无统计学意义(P0.05)。饲料中添加HMC对全鱼水分和粗蛋白含量影响无统计学意义(P0.05),对全鱼粗灰分和粗脂肪含量影响有统计学意义(P0.05)。石斑鱼血浆铜蓝蛋白(CP)的含量、血清和肝脏总超氧化物歧化酶(T-SOD)及铜锌超氧化物歧化酶(Cu-Zn-SOD)活性均以6.20 mg/kg组最高;饲料中铜的添加对血清谷胱甘肽过氧化物酶(GSH-Px)活性和肝脏硫代巴比妥酸反应物(TBARS)含量影响无统计学意义(P0.05)。与对照组相比,饲料中添加HMC均提高鱼体、肌肉和肝脏中铜含量,差异有统计学意义(P0.05),且以13.96 mg/kg组最高。饲料中添加适量的HMC可提高石斑鱼幼鱼的生长性能,提高抗氧化能力。在本实验条件下,以SGR为判据,通过二次回归方程拟合可得,以HMC为铜源,斜带石斑鱼幼鱼铜需要量为7.09 mg/kg。

Dietary Requirement of Juvenile Grouper,Epinephelus coioides for Hydroxy Methionine Copper

An organic Cu source, hydroxy methionine copper （HMC） was added to a basal diet at 6 levels, and the experimental diets with the Cu mass fraction of 2.03, 4.04, 6.20, I0.67, 13.67 mg/kg respectively were fed to the juvenile grouper （Epinephelus coioides） for 6 weeks, and the effects of HMC supplementation on growth performance, nonspecific immunity enzymes and tissue copper content of the juvenile grouper were studied. The results showed as follows： the weight gain and specific growth rate （SGR） in 4.04, 6.20 and 10.67 mg/kg copper groups were significantly higher than those in control group and 13.67 mg/kg copper group （P〈0.05）, at the same time, the feed efficiency rate was the lowest. No significant differences were found in crude protein, moisture contents ofwhole body among all groups （P 〉 0.05）, while crude lipid and ash contents of whole body were significantly different in control group and all supplemental groups. The highest ceruloplasmin （CP） activities, serum and hepatic total and copper-zinc superoxide dismutase （Cu-Zn SOD） activities were found in 6.20mg/kg group. Serum glutathione peroxidase （GSH-Px） activities and hepatic thiobarbituric acid-reactive substance （TBARS） were not significantly affected by copper supplemental level （P 〉 0.05）. The copper concentration in the whole fish, muscle and liver were linear increased with the increased copper supplementation. According to the above results, it is concluded that Copper HMC can effectively improve growth performance and nonspecific immunity enzymes activity of juvenile grouper Based on quadratic curve equation of copper supplementation and SGR, the optimum requirement for dietary Copper is 7.06 mg/kg.