Effect Of Arginine On Intestinal Mucosal Immunity In Acute Heat Stress Of Chicken

Mucosal immunity plays a very important role against infection.More researches focus on arginine regulation to stress-induced damage for whole organism immune function but less for mucosal immunity.The trial aimed to observe whether arginine act on mucus immunity under stress conditions.135 one-day-old broilers were randomly assigned to three groups.The chickens were fed with basal diet,basal diet with addition of 0.3%arginine and 0.6%arginine in control group,experimental group 1 and experimental group 2 respectivly.Acute heat stress was preformed at 35-day-old.Tissue samples of small intestine(duodenum,jejunum and ileum) in three groups were taken to observe the parameters by histological and immunohistochemistrical method and chemical analysis way at different time point(before stress,under stress(39±1℃,3h),after stress(suffering from actue heat stress 3h and recovering 3h at 25℃).These parameters referred to villus height,the number of goblet cells,the number of intraepithelial lymphocyte(IEL),the mean density(MD) of secreted IgA(sIgA) secretory cells in duodenum and jejunum and ileum,the rate of the peripheral blood T_ANAE⁺,intestinal mucosa nitric oxide(NO) levels and total antioxidant capacity(T-AOC).The trial aim to observe effect of arginine on mucosal immunity of chicken in actue heat stress.The results indicated:1.Arginine had the function of safeguarding the intestinal mucosal mechanical barrier under stress.In the control group,it was significant that the duodenum and jejunum' villi was higher before stress than that in stressing and after stress(P＜0.05),but the number of the goblet cell increased obviously in whole intestine(P＜0.01).The duodenum and jejunum' villi in experimental group 1 was higher than that in control group before stress(P＜0.01).In the experimental group 2,the number of the goblet cell in whole intestine was more than that in control group significantly(P＜0.01).In stressing,both the villi height and the number of the goblet cell in the duodenum and jejunum were increased comparing with the control group(P＜0.01).In the experimental group 2,the number of the goblet cell in the duodenum and jejunum was more than that in the control group(P＜0.01) and the height of jejunum'villi was higher than that in control group.After stress,there was no significant among three groups in the height of villi and the number of goblet cell.These results indicated that the villi of duodenum and jejunum were damaged significantly in stressing,while heat stress could increase the number of goblet cells in the small intestine significantly.Exogenous arginine can relief the injury of enteric mucosa by increasing the height of villi and the number of goblet cells.2.Arginine had the function of safeguarding the intestinal mucosal immune barrier under stress.The number of the IEL in the duodenum and the jejunum reduced significantly in the control group under stress(P＜0.01)) and the MD of s[gA secretory cells in the duodenum reduced significantly too(P＜0.05).But the number of the IEL and the MD of sIgA secretory cells in the ileum did not change significantly.It was obvious that arginine can increase the number of the IEL and the MD of sIgA secretory cells.It could be seen that the number of the IEL and the MD of sIgA secretory cells were increased in the experimental group 1 and experimental group 2 significantly(P＜0.01) in the duodenum and the ileum comparing with the control group before stress.In stressing,the number of the IEL and the MD of sIgA secretory cells in the duodenum and the jejunum significantly increased in the experimental group 1(P＜0.01),but the number of the IEL lowed in the duodenum(P＜0.01) in the experimental group 2 comparing with control group.After stress,in the experimental group 1,the number of the IEL in the duodenum and the jejunum increased significantly,the MD of sIgA secretory cells in the ileum and the ileum increased significantly too.The results showed that no matter in normal environment or in heat stressing,the proper level of exogenous arginine can improve the number of sIgA secretory cells and IEL in small intestine.3.Arginine had the function of enhancing the Cellular immune function under stress.The percentage of T_ANAE⁺ decreased significantly under stress(P＜0.01).The percentage of T_ANAE⁺ in the experimental group 1 was higher than that in the control group before stress(P＜0.05).There was no significant with experimental group 2 and control group before stressing(P＞0.05).The percentage of T_ANAE⁺ in the experimental group 1 and experimental group 2 was higher than that in the control group in stressing(P＜0.05).The results showed that arginine can improve the immune function of T cells significantly.4.Arginine had the function of increasing the content of T-AOC and NO in intestinal mucosa under stress.The T-AOC of the jejunal mucosa in the control group decrease significantly under heat stress(P＜0.05).The content of NO in the jejunal mucosa,ileal mucosa in the control group increased significantly,before stress,the T-AOC of the duodenum in the experimental group 1 was higher than that in the control group(P＜0.05),in the experimental group 2,the antioxidant capacity of the Jejunum and the ileum was higher than control group(P＜0.05),in the experimental group 1 and in the experimental group 2, the nitric oxide ability of the intestinal mucosa were higher than in the control group(P＜0.01);In the stressing,the T-AOC of the duodenum,the jejunum and the ileum and the NO content of the duodenum were higher significantly than the control group(P＜0.05), Which T-AOC of the jejunum,ileum and NO content of the duodenum significantly higher than in the control group(P＜0.01),in the experimental group 2,the NO content and the T-AOC of the intestinal mucous except the T-AOC in the ileum were higher significantly than the control group(P＜0.01);After stress,in the experimental group 1 and in the experimental group 2,the T-AOC of the duodenum and the jejunum were higher significantly than the control group(P＜0.01),the NO content of the jejunum mucous and the ileum mucous in the experimental group 2 were higher significantly than the control group(P＜0.01),the other were lower than the control group.The results showed that:heat stress can cause T-AOC of intestinal mucosa decreasing and the content of NO in intestinal mucosa increasing.Arginine may increase T-AOC of intestinal mucosa and the content of NO in intestinal mucosa at normal temperature and heat stress.Through this experiment,we can conclude that:Heat stress can cause intestinal mucosal barrier injuried and the function of T lymphocytes in the blood was inhibited. Arginine had the function of safeguarding the intestinal mucosal barrier and protected the lymphocyte in normal conditions and under stress.But,these function of arginine concerned with intestinal site and the level of arginine.