饲粮添加异亮氨酸对轮状病毒攻毒断奶仔猪回肠屏障功能的影响

Effects of Dietary Isoleucine on Ileal Barrier Function of Weaned Piglets Challenged by Rotavirus

本研究旨在探讨饲粮添加异亮氨酸是否可以缓解轮状病毒(RV)感染对断奶仔猪回肠屏障功能的影响。在细胞试验中,用8 mmol/L的L-异亮氨酸处理IPEC-J2细胞24 h;在动物饲养试验中,选取28头健康的21日龄断奶的"杜×长×大"仔猪,采用2×2双因子设计,即饲粮处理(添加1%L-异亮氨酸饲粮或添加0.68%L-丙氨酸饲粮)和RV攻毒(灌服RV或无菌培养液),RV攻毒于试验第15天早上进行。试验期为18 d。结果表明,L-异亮氨酸处理提高了IPEC-J2细胞中黏液蛋白2(mucin 2)、闭锁小带蛋白-1(ZO-1)和闭合蛋白(occludin)的mRNA相对表达量(P<0.05);RV攻毒提高了断奶仔猪平均腹泻指数和血清二胺氧化酶活性(P<0.05),提高了回肠黏膜中RV的非结构蛋白4阳性率,降低了断奶仔猪回肠黏膜中mucin 2、ZO-1和occludin mRNA相对表达量(P<0.05);而饲粮添加异亮氨酸缓解了RV攻毒对断奶仔猪平均腹泻指数、血清二胺氧化酶活性和回肠黏膜mucin 2、ZO-1和occludin mRNA相对表达量的影响(P<0.05),降低了回肠黏膜中RV的非结构蛋白4阳性率。综上所述,在断奶仔猪的饲粮中补充1%异亮氨酸可以预防RV诱导发生的腹泻,而这一作用与其可改善回肠屏障功能有关。

This experiment was conducted to determine whether dietary isoleucine alleviated the effects of rotavirus(RV)infection on ileal barrier function of weaned piglets.In cell culture experiment,IPEC-J2 cells were treated by 8 mmol/L L-isoleucine for 24 h.In animal breeding experiment,twenty-eight healthy crossbred(Duroc×Landrace×Yorkshire)piglets weaned at 21 days of age were used in a 2×2 factorial design.The trial factors included diet treatment(adding 1%L-isoleucine diet or adding 0.68%L-alanine diet)and RV challenge(infusing RV or sterile culture solution).On day 15,RV challenge was carried out.The trial duration was 18 days.The results showed that L-isoleucine treatment increased mRNA relative expression of mucin 2,zonula occludens-1(ZO-1)and occludin in IPEC-J2 cells(P<0.05).RV challenge increased average diarrhea index and serum diamine oxidase activity(P<0.05),enhanced RV nonstructural protein 4 positive rate in ileal mucosa,and reduced mRNA relative expression of mucin 2,ZO-1 and occludin in ileal mucosa of weaned piglets(P<0.05).Dietary isoleucine relieved the effects of RV challenge on average diarrhea index,serum diamine oxidase activity,and mRNA relative expression of mucin 2,ZO-1 and occludin in ileal mucosa(P<0.05),and decreased RV nonstructural protein 4 positive rate in ileal mucosa of weaned piglets.These results suggest that dietary 1%isoleucine can prevent the RV-induced diarrhea,which is associated with the improvement of ileal barrier function of weaned pigs.