The Effect Of Dietary L-isoleucine Supplementation On Growth Performance,immune Function In The Weaned Piglets Infected By Rotavirus

The present research aimed to determine how dietary L-isoleucine administration improves the growth performance and immune response in weaned piglets with RV infection.This study include one cell culture experiment and one in vivo experiment.In cell culture experiment,after IPEC-J2 and 3D4/31 cells were treated by 8 m M L-isoleucine for 24 h,the gene expressions ofβ-defensins and pattern recognition receptors（PRRs）signaling pathway were significantly increased.Then,in the in vivo experiment,Forty-two crossbred weaned pigs were randomly divided into three groups fed with basal diet with or dietary two levels of L-isoleucine（0.5%or 1%）for 18 d.On the 15^thday,the oral RV gavage was executed in the half of piglets.（1）ADFI and G of piglets were impaired by RV infection（P<0.05）.（2）RV infection also induced severe diarrhea and the increasing serum urea nitrogen concentration（P<0.05）,（3）RV infection decreased CD4⁺lymphocyte and CD4⁺/CD8⁺ratio of peripheral blood（P<0.05）,（4）And RV infection regulated the productions and/or expressions of immunoglobulins,RV antibody,cytokines andβ-defensins in serum,ileal mucosa and/or mesenteric lymph nodes of weaned piglets（P<0.05）,up-regulated the expression of genes related to innate immune response（P<0.05）.（5）In addition,RV infection also significantly decreased the production of MUC2 and the m RNA expression of MUC2,ZO-1 and Occludin in ileal mucosa of weaned piglets（P<0.05）.（6）However,dietary L-isoleucine supplementation attenuated diarrhea and decreasing growth performance（P<0.05）,（7）enhanced the levels of Ig A,Ig G,RV antibody,cytokines andβ-defensins in serum and ileum,and up-regulated the Mrna expression of some cytokines,β-defensins and genes related to innate immune response（P<0.05）in the weaned pigs challenged by RV.（8）Furthermore,L-Ile administration also relieved the decrease of MUC2 concentration and the expression of MUC2,ZO-1 and Occludin in ileum of RV infected piglets.These present results indicate that dietary L-isoleucine administration improve the growth performance,intestinal barrier function and immune response of weaned piglets,which could be derived from L-isoleucine treatment improving the innate and adaptive immune responses via activation of PRRs signaling pathway in RV-infected piglets.It is possible that L-isoleucine can be used in the therapy of RV infection in infants and young animals.