本试验旨在研究饲粮亚油酸水平对育成期蓝狐生长性能、营养物质消化率及氮代谢的影响。选取（90±5）日龄、体重相近的健康雄性蓝狐60只，随机分成6组，每组10个重复，每个重复1只蓝狐。6组蓝狐分别饲喂亚油酸水平为0.11%（Ⅰ组）、0.52%（Ⅱ组）、0.92%（Ⅲ组）、1.33%（Ⅳ组）、2.14%（Ⅴ组）和3.36%（Ⅵ组）的试验饲粮。预试期7 d，正试期63 d。结果表明：1）饲粮亚油酸水平极显著影响育成期蓝狐的平均日增重和料重比（P<0.01），对干物质采食量无显著影响（P>0.05）。随饲粮亚油酸水平由0.92%升高到3.36%，平均日增重逐渐升高，料重比逐渐降低，但上述指标Ⅳ和Ⅴ组间差异不显著（P>0.05）。2）饲粮亚油酸水平极显著影响育成期蓝狐的脂肪、碳水化合物及干物质消化率（P<0.01），对蛋白质消化率无显著影响（P>0.05）。脂肪和碳水化合物消化率均以Ⅵ组最高，干物质消化率以Ⅴ组最高，但上述3个指标在Ⅳ和Ⅴ组间均无显著差异（P>0.05）。3）饲粮亚油酸水平显著或极显著影响粪氮、尿氮和蛋白质生物学价值（P<0.01或P<0.05），对食入氮、氮沉积和净蛋白质利用率无显著影响（P>0.05）。粪氮以Ⅵ组最高，与Ⅱ、Ⅳ和Ⅴ组差异不显著（P>0.05）。尿氮以Ⅱ组最高，与Ⅲ、Ⅳ和Ⅴ组差异不显著（P>0.05）。Ⅵ组蛋白质生物学价值最高，显著高于Ⅱ组（P<0.05），与其他组差异不显著（P>0.05）。从降低环境污染以及保证育成期蓝狐生长性能的角度综合考虑，饲粮亚油酸水平为2.14%较适宜。

This study was conducted to study the effects of dietary linoleic acid level on growth performance, nutrient digestibility and nitrogen metabolism of blue foxes in growing period. Sixty male blue foxes aged about 90 days with similar body weight were randomly divided into 6 groups with 10 replicates per group and 1 fox per replicate. They were fed experimental diets with linoleic acid levels of 0.11% (group Ⅰ), 0.52% (group Ⅱ), 0.92% (group Ⅲ), 1.33% (group Ⅳ), 2.14% (group Ⅴ) and 3.36% (group Ⅵ), respectively. The adaptation period lasted for 7 days and the formal period lasted for 63 days. The results showed as follows: 1) dietary linoleic acid level had significant effects on the average daily gain and feed/gain (P<0.01), but had no significant effect on the dry matter intake (P>0.05). The average daily gain was gradually increased with dietary linoleic acid level increased from 0.92% to 3.36%, while the feed/gain was gradually declined, but no significant differences were found in above indices between groups Ⅳ and Ⅴ (P>0.05). 2) Dietary linoleic acid level had significant effects on the fat digestibility, carbohydrate digestibility and dry matter digestibility (P<0.01), but had no significant effect on the protein digestibility (P>0.05). The highest values of fat digestibility and carbohydrate digestibility were found in group Ⅵ, and the highest value of dry matter digestibility was found in group Ⅴ, but no significant differences were found in above indices between groups Ⅳ and Ⅴ (P>0.05). 3) Dietary linoleic acid level had significant effects on fecal nitrogen, urea nitrogen and biological value of protein (P<0.05 or P<0.01), but had no significant effects on nitrogen intake, nitrogen retention and net protein utilization (P>0.05). The fecal nitrogen in group Ⅵ was the highest, but had no significant difference compared with groups Ⅱ, Ⅳ and Ⅴ (P>0.05); the urea nitrogen in group Ⅱ was the highest, but had no significant difference compared with groups Ⅲ, Ⅳ and Ⅴ (P>0.05); the biological value of protein in group Ⅵ was the highest, and was significantly higher than that in group Ⅱ (P<0.05), but had no significant difference compared with other groups (P>0.05). By a comprehensive consideration on the terms of reducing environmental pollution and maintaining growth performance, dietary optimal linoleic acid level for blue foxes in growing period is 2.14%.