低蛋白质日粮中添加赖氨酸和蛋氨酸对生长前期蓝狐消化代谢及生产性能的影响

Effects of Diet of Low Protein with Supplement of Lys and Met on the Digestive Metabolic and Growth Performance of Blue Fox at Its Early Growth Stage

本试验旨在探讨降低日粮中蛋白质水平同时补充适当的限制性氨基酸对生长前期蓝狐消化代谢及生产性能的影响。随机选取75只8周龄健康公蓝狐，随机分成5组，每组15个重复，每个重复1只蓝狐。对照组日粮蛋白质水平为28．7％，试验组日粮初始蛋白质水平分别为27．4％（Ⅰ组）、24．5％（Ⅱ组）、23．2％（Ⅲ组）和22．4％（IV组），然后分别加入相应量的赖氨酸和蛋氨酸，使其水平与对照组相当。结果表明：与对照组相比，当日粮中蛋白质水平降到27．4％并加入相应量的赖氨酸和蛋氨酸，其终体重、日增重、氮沉积极显著升高（P〈0．01），饲料转化率、氮沉积率和氮生物学效价显著升高（P〈0．05）；当日粮中蛋白质水平降到23．2％并加入相应量的赖氨酸和蛋氨酸，蓝狐的消化代谢及生长性能的各项指标均差异不显著（P〉0．05）。综合各项试验指标，蓝狐生长前期日粮蛋白质水平降低1．0～1．5个百分点并添加相应量的赖氨酸和蛋氨酸，可显著提高蓝狐消化率、代谢率和生产性能；降低2．0～4．0个百分点并添加相应的赖氨酸和蛋氨酸，对蓝狐消化代谢及生产性能无显著影响；此外，添加限制性氨基酸的低蛋白质日粮降低了蓝狐的饲养成本，减少了氮排泄量。

The experiment was conducted to explore the effects of diet of low protein level with supplement oi limited ammno acid on the metabolic, digestive and growth performance of blue fox at its early growth stage. Seventy-five healthy male blue foxes of 8-week-old were randomly divided into 5 groups with 15 replicates in each replicate which had i fox in it. Protein level of diet of the control group was 28.7%, the primary protein levels in the experiment groups were 27.4% （group Ⅰ ）, 24.5% （groupⅡ）, 23.2% （group Ⅲ）and 22.4% （group Ⅳ） respectively, and then appropriate amount of Lys and Met were supplemented to meet their level requirement which was the same with that of the control group. The results showed that, compared with control group, when the protein level was reduced to 27.4% but the corresponding amounts of the Lys and Met were added into the diets , the final weight, ADG and N retention were significantly higher （P〈0.01）, and the FCR, N retention ratio and N biological value were also increased greatly （P〈0.05）. When the protein level in the diet was reduced to 23.2% and the corresponding amounts of the Lys and Met were added, no significant differences were observed on the digestive, metabolic and growth performances of blue foxes （P〈0.05）. On the basis of all indices of experiment, when the protein level was reduced by 1%- 1.5 % and the corresponding amounts of the Lys and Met were added into diets, it can significantly improve digestive, metabolic and growth performance of blue fox. When the protein level was reduced by 2%-4% with supplement of corresponding amounts of Lys and Met in diets, there were no significant effects on the digestive, metabolic and growth performance of blue fox. Besides, low protein diet with supplement of the limited amino acid also reduced the breeding cost and N excreting amount of the blue fox.