亚东鲑幼鱼饲料蛋白和脂肪适宜水平的研究

A STUDY ON THE PROPER PROTEIN AND LIPID LEVELS IN THE DIET OF SALMO TRUTTA JUVENILES

为考察饲料蛋白和脂肪水平对亚东鲑(Salmo trutta)幼鱼生长性能、体组成、肝脏生化指标和肠道酶活性的影响,实验采用3×2双因子设计,蛋白水平为42%、46%和50%(P42、P46、P50),脂肪水平为12%和16%(L12、L16),共6组饲料,饲养平均体重(2.80±0.10) g的亚东鲑幼鱼56d。结果表明, P46L12组增重率最高(110.34%),饲料系数最低(1.3),而P50L16组的增重率最低;各组在脏体比之间无显著差异(P>0.05);肝体比随着蛋白和脂肪水平的增加呈现降低的趋势;蛋白沉积率和脂肪沉积率随着饲料蛋白的升高先上升后下降。饲料脂肪水平对肠蛋白酶,胃蛋白酶和胃淀粉酶活性均有显著影响(P<0.05),饲料蛋白水平仅对胃蛋白酶活性有显著影响(P<0.05);P46L12组的肠道蛋白酶,胃蛋白酶活性显著高于其他各组(P<0.05),胃、肠淀粉酶活性在各组中也最高。在同一脂肪水平下,肝脏谷丙转氨酶活性和总胆固醇和甘油三酯含量随着饲料粗蛋白水平的增加呈现先上升后下降的趋势。上述结果表明,亚东鲑幼鱼饲料中粗蛋白和粗脂肪的适宜水平分别为46%和12%。

This study was conducted to evaluate the effects of dietary protein and lipid levels on the growth performance, body composition, liver biochemical index and intestinal enzyme activity of juvenile brown trout. The experiment used a 3×2 two-factor design with protein levels of 42%, 46%, and 50%(P42, P46, and P50) and lipid levels of12% and 16%(L12, and L16). Brown trout with an average initial weight of(2.80±0.10) g were randomly distributed into six groups with three fish per group and fed with one of the six diets for 56 d. The results indicated that the P46 L12 group had the highest weight gain(110.34%) and the lowest feed coefficient ratio(1.30), while the P50 L16 group showed the lowest growth. There was no significant difference in the viscerosomatic index among all groups(P>0.05).The hepatosomatic index decreased with increasing dietary protein and fat levels. With the increase of dietary protein levels, the protein retention and lipid retention first increased and then decreased. Dietary lipid levels significantly affected the activity of intestinal protease, pepsin and gastric amylase activity(P<0.05), while dietary protein levels only affected pepsin activity(P<0.05). The P46 L12 group had the highest protease and amylase activities in the stomach and intestine among those of all groups. At the same fat level, glutamic-pyruvic transaminase(GPT) activity and total cholesterol(TC) and triglyceride(TG) contents first increased and then decreased with increasing dietary protein levels.The above results indicated that the proper levels of crude protein and crude lipid in the diet of juvenile brown trout were 46% and 12%, respectively.