肌醇对大规格吉富罗非鱼生长、体组成和血清指标的影响

摘要

采用肌醇水平分别为0 mg·kg–1、100 mg·kg–1、200 mg·kg–1、400 mg·kg–1、800 mg·kg–1和1600 mg·kg–1饲料的6组等氮等能实验饲料,养殖初始体质量(74.36±5.32)g的吉富罗非鱼(GIFT Oreochromis niloticus)12周,通过测定生长、鱼体成分以及血清指标来综合评价饲料肌醇水平对罗非鱼的影响,以期获得大规格吉富罗非鱼对饲料肌醇的需要量.结果表明,饲料中添加肌醇可显著提高罗非鱼增重率、采食量和饲料系数(P<0.05);对增重率与饲料肌醇水平作二次回归分析,得出其需要量为847 mg·kg–1饲料;罗非鱼全鱼、肌肉和肝脏中的粗脂肪含量均随饲料肌醇添加量的增加而降低;添加肌醇对罗非鱼肌肉、肝脏粗蛋白含量均无显著影响(P>0.05).当肌醇水平为800 mg·kg–1和1600 mg·kg–1饲料时,血清谷丙转氨酶和谷草转氨酶活性均较对照组显著降低(P<0.05);随饲料中肌醇含量的升高,总胆固醇和甘油三酯含量呈现先降低后升高的趋势,而血糖呈现先升高后降低的趋势.综上所述,大规格吉富罗非鱼饲料中肌醇的需要量为847 mg·kg–1饲料,且饲料中添加肌醇有利于降低组织脂肪蓄积,并可改善肝功能.%The tilapia(GIFT Oreochromis niloticus)with initial body mass of(74.36±5.32)g were fed by diets at six myo-inositol (MI) levels (0 mg·kg–1, 100 mg·kg–1, 200 mg·kg–1, 400 mg·kg–1, 800 mg·kg–1and 1 600 mg·kg–1) diets for 12 weeks, so as to invest-igate the effect of MI on tilapia. We measured their growth performance, body composition and serum biochemical indices, and fi-nally determined the requirement of dietary MI for large size GIFT O.niloticus.The results show that the dietary MI increased the weight gain rate (WGR), feed intake and feed conversion ratio significantly compared with the control group (P<0.05). According to the second-order polynomial regression analyses based on WGR and dietary MI level, the optimum MI requirement was 847 mg·kg–1. The crude fat contents in the liver, muscle and whole body of tilapia decreased with increasing dietary MI level, but the crude protein contents in muscle and liver showed no significant difference among groups (P>0.05). The activities of aspartate aminotransferase and alanine aminotransferase in serum were significantly lower in 800 mg·kg–1and 1 600 mg·kg–1MI groups than those in the control (P<0.05). With increasing dietary MI level, the total cholesterol and triacylglyceroln contents in serum firstly deceased and then incr-eased, but the glucose contents in serum showed an opposite trend. In conclusion, the diet with 847 mg·kg–1MI is optimal for large size GIFT O.niloticus,and appropriate dietary MI supplementation is beneficial to reducing tissue fat accumulation and improving liver function.