饲料鱼粉、菜粕比例对异育银鲫生长和饲料利用的影响

通过在饲料中配制不同鱼粉和菜粕比例，探讨利用菜粕蛋白替代鱼粉对异育银鲫（Carssius auratus gibelio）的生长和饲料利用的影响。饲料中菜粕蛋白替代鱼粉蛋白的比例分别为 0、20%、40%、60% 和80%。实验结果表明，当饲料中菜粕蛋白比例高于40%时，异育银鲫的生长显著下降（P0.05），对摄食率影响不明显（P0.05）。在80%替代水平下，干物质和蛋白质的消化率最低，能量消化率在40%替代水平最低。饲料转化效率在20%蛋白替代后明显下降（P0.05）。蛋白质和能量储积率在40%蛋白替代后明显下降（P0.05）。在40%菜粕蛋白下，鱼体能量和脂肪含量最高。鱼体蛋白质在60% 和80% 菜粕蛋白时最低，脂肪在20% 菜粕蛋白时最高。因此饲料菜粕蛋白的水平不超过20%（干物质含量约17%）不会影响异育银鲫的生长和饲料转化。  

EFFECTS OF DIETARY RATIO OF FISH MEAL AND RAPESEED MEAL ON THE GROWTH AND FEED UTILIZATION IN GIBEL CARP(CARASSIUS AURATUS GIBELIO)

Effects of replacement of fish meal with rapeseed meal on the growth and feed utilisation were investigated in juvenile gibel carp (Carssius auratus gibelio). Three groups of fish were fed with each of five groups of diets supplemented with different concentrations of rapeseed: 0, 20%, 40%, 60% and 80% of total dietary protein. The experiment was carried out in a recirculation system at 26.5-29.5℃ (mean 28.5℃) for 8 weeks. The results showed that the growth rate of the fish decreased significantly when the rapeseed protein accounted for 40%, or higher, of the total dietary proteins. The feed intake was not affected by the concentration of rapeseed. The digestion rate of the dry matter and protein was significantly lower only when the concentration of rapeseed protein was 80% of the total dietary proteins. The digestion rate of energy was the lowest when rapeseed protein accounted for 40% of the total. Feed conversion efficiency decreased significantly when the dietary rapeseed protein concentration was 20% or higher. The protein and energy retention efficiency decreased when dietary rapeseed protein concentration was 40% or higher. The body energy and fat content reached the highest values when the fish was fed with the diet containing 40% rapeseed protein. The body protein level was lowest at the rapeseed protein concentrations of 60% and 80%, while the fat content was highest at 20%. Based on the data we suggest that the optimal concentration of rapeseed protein should be 20% in the diet for gibel carp.