Effect of Arginine Supplementation on Genes Expression of Toll-like Receptors in Intestinal Tissues of Weaned Piglets under Immune Stress

This trial was conducted to study the effect of arginine(Arg) supplementation on growth performance and genes expression of cell-surface toll-like receptors(TLR2,TLR4,TLR5 and TLR6) in intestinal tissues of weaned piglets under immune stress.Twenty male weaned piglets [(Duroc×Landrace×Yorkshire),(24±1) days of age,average body weight of(7.19±0.63) kg] were randomly assigned to 4 treatments with 5 replicates in each treatment and 1 piglet per replicate.Piglets were fed basal diet+injected sterile saline(control group),fed basal diet+injected live vaccine of Salmonella choleraesuis 500(S.C500)(S.C500 group),fed basal diet supplemented with 0.5% Arg+injected S.C500(0.5% Arg group),and fed basal diet supplemented with 1.0% Arg+injected S.C500(1.0% Arg group),respectively.The injection of 4 mL S.C500 or sterile saline was carried out on day 8.The trial lasted for 17 d.Blood samples were collected to determine serum Salmonella antibody level and interleukin-6(IL-6) concentration on day 8(before injection),day 9,day 11 and day 18.Piglets were slaughtered and jejunum and ileum tissue samples were collected for evaluation of mRNA expression levels of toll-like receptors on day 18.The results showed as follows: compared with the control group,injection of S.C500 decreased the ADG(P0.10) and ADFI(P0.05) of piglets to a different extent,significantly increased serum IL-6 concentration on day 9,day 11 and day 18(P0.05),as well as mRNA expression levels of TLR4 and TLR5 in jejunum and ileum tissue(P0.05);Arg supplementation(0.5% and 1.0%) alleviated inhibitive effects induced by S.C500 challenge,decreased serum IL-6 concentration,and inhibited mRNA expression levels of TLR4 and TLR5 in jejunum and ileum tissue(P0.05).These results indicate that Arg supplementation can alleviate the over-expression of TLR4 and TLR5 mRNA in intestinal tissues and the excessive production of serum IL-6 induced by S.C500 challenge,which are beneficial to alleviating damage induced by immune stress.