本试验旨在研究饲粮中添加枯草芽孢杆菌和粪肠球菌对育成期蓝狐生长性能、营养物质消化率及氮代谢的影响。选择（55±5）日龄健康蓝狐84只，随机分成7组，每组12个重复，每个重复1只。Ⅰ组为对照组，饲喂基础饲粮，Ⅱ、Ⅲ、Ⅳ组在基础饲粮中分别添加1×10⁸、1×10⁹、1×10¹⁰ CFU/kg的枯草芽孢杆菌，Ⅴ、Ⅵ、Ⅶ组在基础饲粮中分别添加1×10⁸、1×10⁹、1×10¹⁰ CFU/kg的粪肠球菌。预试期7 d，正试期57 d。结果表明：Ⅲ、Ⅳ、Ⅴ组的平均日增重显著高于对照组（P<0.05），Ⅲ、Ⅳ组的料重比显著低于对照组（P<0.05）。比较各试验组的平均日增重可知，Ⅲ、Ⅳ组显著高于Ⅶ组（P<0.05）；比较各试验组的料重比可知，Ⅲ、Ⅳ组显著低于Ⅶ组（P<0.05）。Ⅲ、Ⅳ、Ⅴ组的干物质排出量显著低于对照组（P<0.05）。Ⅲ、Ⅳ、Ⅴ组的干物质消化率和蛋白质消化率显著高于对照组（P<0.05）。Ⅲ、Ⅳ组的脂肪消化率极显著高于对照组（P<0.01），其余试验组与对照组相比差异不显著（P>0.05）。比较各试验组的脂肪消化率可知，Ⅲ、Ⅳ组显著高于Ⅱ组（P<0.05），极显著高于Ⅵ、Ⅶ组（P<0.01）。与对照组相比，Ⅵ、Ⅶ组的氮沉积显著降低（P<0.05），其余各试验组均有所升高，其中Ⅲ、Ⅳ、Ⅴ组与对照组的差异达显著或极显著水平（P<0.05或P<0.01）。Ⅱ、Ⅲ、Ⅳ、Ⅴ组的净蛋白质利用率和蛋白质生物学价值极显著高于Ⅵ、Ⅶ组（P<0.01），且Ⅲ、Ⅳ、Ⅴ组还显著高于对照组（P<0.05）。结果提示，饲粮中添加1×10¹⁰ CFU/kg枯草芽孢杆菌或1×10⁸ CFU/kg粪肠球菌时育成期蓝狐的营养物质消化率、氮沉积、净蛋白质利用率、蛋白质生物学价值较为理想，且可获得较好的生长性能。

This experiment was conducted to study the effects of Bacillus subtilis and Enterococcus faecium supplementations on growth performance, nutrient digestibility and nitrogen metabolism of growing blue foxes. Eighty-four healthy blue foxes at the age of (55±5) days were randomly assigned into 7 groups with 12 replicates per group and 1 fox per replicate. Group Ⅰ (control group) was fed a basal diet, groups Ⅱ, Ⅲ and Ⅳ were fed the basal diet supplemented with 1×10⁸, 1×10⁹ and 1×10¹⁰ CFU/kg Bacillus subtilis, and groups Ⅴ, Ⅵ and Ⅶ were fed the basal diet supplemented with 1×10⁸, 1×10⁹ and 1×10¹⁰ CFU/kg Enterococcus faecium, respectively. The adaptation period lasted for 7 days and the formal period lasted for 57 days. The results showed as follows: the average daily gain in groups Ⅲ, Ⅳ and Ⅴ was significantly higher than that in control group (P<0.05), while the feed/gain in groups Ⅲ and Ⅳ was significantly lower than that in control group (P<0.05). The comparison results of all experimental groups showed that the average daily gain in groups Ⅲ and Ⅳ was significantly higher than that in group Ⅶ (P<0.05), while the feed/gain in groups Ⅲ and Ⅳ was significantly lower than that in group Ⅶ (P<0.05). The output of dry matter in groups Ⅲ, Ⅳ and Ⅴ was significantly lower than that in control group (P<0.05), while the digestibility of dry matter and protein in groups Ⅲ, Ⅳ and Ⅴ was significantly higher than that in control group (P<0.05). The digestibility of fat in groups Ⅲ and Ⅳ was significantly higher than that in control group (P<0.01), while there was no significant difference between control group and other experimental groups (P>0.05). Compared with all experimental groups, the digestibility of fat in groups Ⅲ and Ⅳ was significantly higher than that in groups Ⅱ, Ⅵ and Ⅶ (P<0.05 or P<0.01). The nitrogen retention in groups Ⅵ and Ⅶ was significantly lower than that in control group (P<0.05), while the nitrogen retention in other experimental groups was higher than that in control group, and the difference reached a significant level in groups Ⅲ, Ⅳ and Ⅴ (P<0.05 or P<0.01). The net protein utilization and biological value of protein in groups Ⅱ, Ⅲ, Ⅳ and Ⅴ were significantly higher than those in groups Ⅵ and Ⅶ (P<0.01), and those in groups Ⅲ, Ⅳ and Ⅴ were significantly higher than those in control group (P<0.05). In conclusion, the nutrient digestibility, nitrogen retention, net protein utilization, and the biological value of protein of growing blue foxes are ideal when supplementing 1×10¹⁰ CFU/kg Bacillus subtilis or 1×10⁸ CFU/kg Enterococcus faecium in diets, meanwhile, the blue foxes can also get the optimal growth performance.