饲粮n-6/n-3多不饱和脂肪酸比值对冬毛期北极狐生长性能及肝脏脂肪酸代谢相关蛋白基因表达的影响

摘要

本试验旨在研究饲粮n-6/n-3多不饱和脂肪酸(PUFA)比值对冬毛期北极狐生长性能、肝脏脂肪酸组成及肝脏型脂肪酸结合蛋白(L-FABP)和脂肪酸转运蛋白(FATP)基因表达的影响.试验选取48只157日龄、平均体重为(5 658±47)g的健康雄性北极狐,随机分成4组,每组12个重复,每个重复1只.Ⅰ组饲粮中添加12.00％鱼油和2.00％豆油,n-6/n-3 PUFA比值为3.00;Ⅱ组饲粮中添加9.38％玉米油和4.62％豆油,n-6/n-3 PUFA比值为18.03;Ⅲ组饲粮中添加12.00％玉米油和2.00％豆油,n-6/n-3 PUFA比值为40.83;Ⅳ组饲粮中添加1.50％鱼油和12.50％玉米油,n-6/n-3 PUFA比值为136.36.各组饲粮除油脂组成和配比不同外,其他原料一致.预试期7d,正试期40 d.结果表明:1)饲粮n-6/n-3 PUFA比值对冬毛期北极狐的平均日增重(ADG)、平均日采食量(ADFI)和料重比(F/G)有极显著影响(P＜0.01).Ⅰ和Ⅳ组的ADG极显著高于Ⅱ和Ⅲ组(P＜0.01),Ⅰ、Ⅱ和Ⅳ组的ADFI极显著高于Ⅲ组(P＜0.01),Ⅳ组的F/G极显著低于Ⅱ和Ⅲ组(P＜0.01).2)饲粮n-6/n-3 PUFA比值对冬毛期北极狐肝脏单不饱和脂肪酸(MUFA)、PUFA、n-3 PUFA和n-6 PUFA的含量有显著或极显著影响(P＜0.05或P＜0.0l),对肝脏饱和脂肪酸(SFA)含量无显著影响(P＞0.05).Ⅰ和Ⅳ组肝脏n-3 PUFA含量极显著高于Ⅱ和Ⅲ组(P＜0.01),Ⅱ和Ⅲ组肝脏n-6 PUFA含量极显著高于Ⅰ和Ⅳ组(P＜0.01).3)饲粮n-6/n-3 PUFA比值对冬毛期北极狐肝脏L-FABP mRNA相对表达量无显著影响(P＞0.05),但极显著影响肝脏FATP mRNA相对表达量(P＜0.01).Ⅰ和Ⅳ组肝脏FATP mRNA相对表达量极显著高于Ⅱ和Ⅲ组(P＜0.01).由此可见,饲粮添加1.50％鱼油与12.50％玉米油的混合油脂,即饲粮n-6/n-3 PUFA比值为136.36时,上调了肝脏中FATP基因的表达,增加了肝脏长链脂肪酸的转运及利用效率,促进了冬毛期北极狐的生长.%This experiment was conducted to study the effects of dietary n-6/n-3 polyunsaturated fatty acids (PUFA) ratio on growth performance,liver fatty acid composition and liver-type fatty acid binding protein (L-FABP) and fatty acid transport protein (FATP) gene expression of Arctic foxes during the winter fur-growing period.Forty-eight 157-day-old male Arctic foxes with the average body weight of (5 658±47) g were randomly divided into 4 groups with 12 replicates per group and 1 fox per replicate,and they were fed experimental diets containing 12.00％ fish oil and 2.00％ soybean oil (group Ⅰ),9.38％ corn oil and 4.62％ soybean oil (group Ⅱ),12.00％ corn oil and 2.00％ soybean oil (group Ⅲ),1.50％ fish oil and 12.50％ corn oil (group Ⅳ) with the n-6/n-3 PUFA ratios were 3.00,18.03,40.83 and 136.36,respectively.The oil composition and proportion of diets among groups were different,but the other ingredients were consistent.The experiment was 7 days for adaption and 40 days for trial period.The results showed as follows:1) dietary n-6/ n-3 PUFA ratio extremely significantly affected average daily gain (ADG),average daily feed intake (ADFI) and the ratio of feed to gain (F/G) of Arctic foxes during the winter fur-growing period (P＜0.01).The ADG in groups Ⅰ and Ⅳ was extremely significantly higher than that in groups Ⅱ and Ⅲ (P＜0.01),the ADFI in groups Ⅰ,Ⅱ and Ⅳ was extremely significantly higher than that in group Ⅲ (P＜0.01),and the F/G in group Ⅳ was extremely significantly lower than that in groups Ⅱ and Ⅲ (P＜0.01).2) Dietary n-6/n-3 PUFA ratio extremely significantly or significantly affected liver monounsaturated fatty acids (MUFA),PUFA,n-6 PUFA and n-3 PUFA contents of Arctic foxes during the winter fur-growing period (P＜0.01 or P＜0.05),but had no significant difference in liver saturated fatty acids (SFA) content (P＞0.05).The liver n-3 PUFA content in groups Ⅰ and Ⅳ was extremely significantly higher than that in groups Ⅱ and Ⅲ (P＜0.01),while the liver n-6 PUFA content in groups Ⅱ and Ⅲ was extremely significantly higher than that in groups Ⅰ and Ⅳ (P＜0.01).3) Dietary n-6/n-3 PUFA ratio did not significantly affect liver L-FABP mRNA expression level of Arctic foxes during the winter fur-growing period (P＞0.05),but extremely significantly affected liver FATP mRNA expression level (P＜0.01).The FATP mRNA expression level in groups Ⅰ and Ⅴ was extremely significantly higher than that in groups Ⅱ and Ⅲ (P＜0.01).In conclusion,when the ratio of n-6/n-3 PUFA is 136.36 (adding mixed oils of 1.50％ fish oi1+12.50％ corn oil in the diets),it raises the expression of liver FATP gene,promotes the transportation and utilization efficiency of fatty acids,and improves the growth of Arctic foxes during the winter fur-growing period.