本试验旨在研究饲粮精氨酸水平对育成期雌性蓝狐生长性能、营养物质消化率、氮代谢及血清生化指标的影响。选取(60±5)日龄、体重相近的60只健康雌性蓝狐,随机分为6组,每组10个重复,每个重复1只,在基础饲粮(精氨酸水平1.61%)基础上各组的精氨酸添加水平分别为0(Ⅰ组)、0.2%(Ⅱ组)、0.4%(Ⅲ组)、0.6%(Ⅳ组)、0.8%(Ⅴ组)和1.0%(Ⅵ组),预试期10 d,正试期63 d。结果表明:1)饲粮精氨酸水平极显著影响蓝狐平均日增重(P<0.01),以Ⅴ组最高,Ⅰ组最低;Ⅴ组蓝狐干物质采食量极显著低于Ⅰ组(P<0.01);Ⅴ组和Ⅵ组蓝狐料重比均极显著低于Ⅰ组(P<0.01)。2)饲粮精氨酸水平极显著影响蓝狐粗蛋白质消化率和粗脂肪消化率(P<0.01),Ⅴ组粗蛋白质消化率显著高于Ⅰ组(P<0.05),Ⅵ组粗脂肪消化率极显著低于其他各组(P<0.01);饲粮精氨酸水平对蓝狐碳水化合物消化率和干物质消化率无显著影响(P>0.05)。3)食入氮量以Ⅴ组最低,Ⅰ组最高,2组间差异极显著(P<0.01);Ⅴ组粪氮排出量较Ⅰ组降低11.73%(P<0.05);Ⅴ组氮沉积较Ⅰ组提高20.54%(P<0.05);净蛋白质利用率和蛋白质生物学价值均以Ⅴ组最高,显著或极显著高于Ⅰ组(P<0.01或P<0.05);饲粮精氨酸水平对尿氮排出量无显著影响(P>0.05)。4)Ⅳ组血清碱性磷酸酶活性极显著高于其他各组(P<0.01);Ⅴ组和Ⅵ组血清尿素氮含量极显著低于Ⅰ组、Ⅱ组和Ⅲ组(P<0.01);饲粮精氨酸水平对血清丙氨酸氨基转移酶和天门冬氨酸氨基转移酶活性无显著影响(P>0.05)。综合各项指标,育成期雌性蓝狐饲粮中添加0.8%精氨酸(饲粮总精氨酸水平为2.41%)可提高平均日增重,降低料重比,减少血清尿素氮含量,建议育成期每只雌性蓝狐精氨酸摄入量在4.22~4.24 g/d之间。

This experiment was conducted to study the effects of dietary arginine level on growth performance, nutrient digestibility, nitrogen metabolism and serum biochemical indexes of female blue foxes in growing period.Sixty female blue foxes aged (60±5) days with similar body weight were randomly divided into 6 groups with 10 replicates per group and 1 fox per replicate, and they were fed experimental diets which supplemented with 0 (group Ⅰ), 0.2% (group Ⅱ), 0.4% (group Ⅲ), 0.6% (group Ⅳ), 0.8% (group Ⅴ) and 1.0% (group Ⅵ) arginine on the basis of a basal diet, respectively.The adaptation period lasted for 10 days and the formal period lasted for 63 days.The results showed as follows: 1) dietary arginine level had a significant effect on the average daily gain (P<0.01) which in group Ⅴ was the highest and in group Ⅰ was the lowest; the dry matter intake in group Ⅴ was significantly lower than that in group Ⅰ (P<0.01); the feed/gain in groups Ⅴ and Ⅵ was significantly lower than that in group Ⅰ (P<0.01).2) Dietary arginine level had significant effects on the digestibility of crude protein and ether extract (P<0.01).The digestibility of crude protein in group Ⅴ was significantly higher than that in group Ⅰ (P<0.05), and the digestibility of ether extract in group Ⅵ was significantly higher than that in other groups (P<0.01).Dietary arginine level had no significant effects on the digestibility of dry matter and carbohydrate (P>0.05).3) The nitrogen intake in group Ⅴ was the lowest and in group Ⅰ was the highest, and the significant difference was found in groups Ⅰ and Ⅴ (P<0.01).The fecal nitrogen output in group Ⅴ was decreased by 11.73% compared with group Ⅰ (P<0.05).The nitrogen retention in group Ⅴ was increased by 20.54% compared with group Ⅰ (P<0.05).The net protein utilization and biological value of protein in group Ⅴ were both the highest, which were significantly higher than those in group Ⅰ (P<0.01 or P<0.05).Dietary arginine level had no significant effect on urea nitrogen output (P>0.05).4) Serum alkaline phosphatase activity in group Ⅳ was significantly higher than that in other groups (P<0.01).Serum urea nitrogen content in groups Ⅴ and Ⅵ was significantly higher than that in groups Ⅰ, Ⅱ and Ⅲ (P<0.01).Dietary arginine level had no significant effects on serum alanine aminotransferase and aspartate aminotransferase activities (P>0.05).Considering all indexes, the 0.8% is considered to be an optimal supplemental level of arginine in the diet (dietary total arginine level is 2.41%) for female blue foxes in growing period which can improve average daily weight, and decrease feed/gain and serum urea nitrogen content.It is recommended that the arginine intake of each female blue fox in growing period is between 4.22 to 4.24 g/d.