本试验旨在研究饲粮中黄芪多糖（APS）添加水平与n-6/n-3多不饱和脂肪酸（PUFA）配比互作对育成生长期北极狐生长性能及血清生化指标的影响。采用双因素试验设计，以黄芪多糖添加水平（0和160 mg/kg）和n-6/n-3 PUFA配比（3和9）为试验因素。在预饲7 d不添加APS、n-6/n-3 PUFA配比为3的基础饲粮以适应干粉饲粮后，将102日龄、健康的48只雄性北极狐随机分成4组，每组12个重复，每个重复1只。1和2组北极狐饲喂不添加APS、n-6/n-3 PUFA配比分别为3和9的饲粮，3和4组北极狐饲喂添加160 mg/kg APS、n-6/n-3 PUFA配比分别为3和9的饲粮。正试期46 d。结果显示：1）102~125日龄阶段，未添加APS组平均日增重（ADG）极显著高于添加160 mg/kg APS组（P<0.01），n-6/n-3 PUFA配比为9时料重比（F/G）极显著高于n-6/n-3 PUFA配比为3时（P<0.01）；4组之中，2组的ADG最高，F/G最低。125~147日龄阶段，添加160 mg/kg APS组ADG显著高于未添加APS组（P<0.05），且F/G极显著低于未添加APS组（P<0.01）；4组之中，4组的ADG最高，F/G最低。饲粮中APS添加水平与n-6/n-3 PUFA配比互作极显著影响102~125日龄和125~147日龄平均日采食量（ADFI）（P<0.01），且2个日龄阶段均以1组ADFI最高。2）添加160 mg/kg APS组血清中葡萄糖（GLU）含量显著低于未添加APS组（P<0.05），n-6/n-3 PUFA配比为9时血清中GLU含量极显著低于n-6/n-3 PUFA配比为3时（P<0.01），最终表现为4组血清GLU含量最低；饲粮中APS添加水平或n-6/n-3 PUFA配比单一作用或二者互作对血清甘油三酯（TG）、胆固醇（CHO）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C）含量均无显著影响（P>0.05）。3）饲粮中APS添加水平和n-6/n-3 PUFA配比互作极显著或显著影响了血清中免疫球蛋白M（IgM）和白细胞介素-2（IL-2）含量（P<0.01或P<0.05），血清IgM含量以4组最高，显著高于2和3组（P<0.05），但血清中IL-2含量各组间差异不显著（P>0.05）；添加160 mg/kg APS组血清免疫球蛋白G（IgG）含量显著高于未添加APS组（P<0.05），4组之中以4组略高，但各组之间差异不显著（P>0.05）。4）添加160 mg/kg APS组血清白球比（A/G）显著低于未添加APS组（P<0.05），4组之中以4组最低；饲粮中APS添加水平或n-6/n-3 PUFA配比单一作用或二者互作对血清中总蛋白（TP）、白蛋白（ALB）和球蛋白（GLOB）含量均未产生显著影响（P>0.05）。综上可知，当饲粮中APS添加水平为160 mg/kg且n-6/n-3 PUFA配比为9时，对血糖具有调节作用，并可增加血清中IgM和IgG的含量，降低血清中A/G，从而提高125~147日龄北极狐的生长性能。

This experiment was conducted to study the Interaction of dietary Astragalus polysaccharide (APS) supplemental level and n-6/n-3 polyunsaturated fatty acid (PUFA) ratio on growth performance and serum biochemical parameters of arctic fox during growing period. A double-factor trial design was used in this experiment. One factor was APS supplemental level which was 0 and 160 mg/kg, respectively. The other factor was n-6/n-3 PUFA ratio which was 3 and 9, respectively. All fox fed a diet without APS and n-6/n-3 PUFA ratio of 3 in order to adapt powdered diet. After feeding 7 days, forty-eight male 102-day-old arctic fox were randomly divided into 4 groups with 12 replicates per group and 1 fox per replicate. The diets without APS and n-6/n-3 PUFA with the ratio of 3 and 9 were used in group 1 and group 2, respectively. The diets with 160 mg/kg APS and n-6/n-3 PUFA with the ratio of 3 and 9 were used in group 3 and group 4, respectively. The trial period was 46 days. The results showed as follows:1) at 102 to 125 days of age, APS supplemental level was 0 mg/kg, the average daily gain (ADG) of arctic fox in unadded APS group was significantly higher than that of added 160 mg/kg APS group (P<0.01), and when the ratio of n-6/n-3 PUFA was 9, the feed/gain (F/G) of arctic fox was significantly higher than that when the ratio of n-6/n-3 PUFA was 3, with the highest ADG and lowest F/G in the group 2. At 125 to 147 days of age, the ADG in added 160 mg/kg APS group was significantly higher than that in un-added APS group (P<0.05), and the F/G was significantly lower than that in un-added APS group (P<0.01). The group 4 had the highest ADG and the lowest F/G among four groups. The interaction between dietary APS supplemental level and n-6/n-3 PUFA ratio significantly affected the average daily feed intake (ADFI) at 102 to 125 and 125 to147 days of age (P<0.01), with the highest ADFI in group 1 those two stages. 2) Serum glucose (GLU) content in added 160 mg/kg APS group was significantly lower than that in un-added APS group (P<0.05), and when the ratio of n-6/n-3 PUFA was 9, the serum GLU content was significantly lower than that when the ratio of n-6/n-3 PUFA was 3 (P<0.01). The group 4 had the lowest GLU content. The interaction between dietary APS supplemental level and n-6/n-3 PUFA ratio or dietary APS supplemental level or n-6/n-3 PUFA ratio had no significant effects on serum triglyceride (TG), cholesterol (CHO), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) contents (P>0.05). 3) The interaction between dietary APS supplemental level and n-6/n-3 PUFA ratio was significantly affected the contents of serum immunoglobulin M (IgM) and interleukin-2 (IL-2). Serum IgM was the highest in group 4, which was significantly higher than that of group 2 and group 3 (P<0.05), but no significant difference in the serum IL-2 content was found among four groups (P>0.05). Serum immunoglobulin G (IgG) content in added 160 mg/kg APS group was significantly higher than that in un-added APS group (P<0.05). Group 4 was slightly higher, but no significant difference was found among four groups (P>0.05). 4) Serum albumin/globulin (A/G) in added 160 mg/kg APS group was significantly lower than that in un-added APS group (P<0.05), which was the lowest in group 4. Dietary APS supplemental level or n-6/n-3 PUFA ratio or the interaction of them had no significant effects on serum total protein (TP), albumin (ALB) and globulin (GLOB) contents (P>0.05). In summary, when dietary APS supplemental level is 160 mg/kg and the ratio of n-6/n-3 PUFA is 9, it has regulation effect on blood glucose, and can increase the contents of serum IgM and IgG, decrease serum A/G, thus improve the growth performance of arctic fox at the age of 125 to 147 days of age.