Effects of Glutamine on Lymphocyte Proliferation and Intestinal Mucosal Immune Response in Heat-Stressed Broilers

ABSTRACT To investigate the protective effect of glutamine (Gln) on lymphocyte proliferation and the intestinal mucosal immune response in heat-stressed broilers, 360 21-day-old Arbor Acres (AA) broilers were assigned to 4 groups in a completely randomized design, each of which included 6 replicates with 15 birds per replicate for 21 days. The chickens were fed a basal diet under no stress (NS group), a basal diet under heat stress (HT group), or a basal diet under heat stress with the addition of either 0.5 % or 1.0 % Gln. The results showed that the broilers in the HT group exhibited fewer proliferating peripheral lymphocytes, a lower growth performance, phagocytic rate and index of neutrophils, fewer goblet cells in whole intestine and intraepithelial lymphocyte (IEL) cells in the ileum, a lower sIgA content in the duodenum and the jejunum, a lower immunoglobulin content of serum and intestinal mucosa, than those of the NS group (p<0.05). Diets supplemented with Gln increased growth performance, the number of proliferating peripheral lymphocytes, the phagocytic rate and phagocytic index of neutrophils, the number of whole intestine goblet cells and ileum IEL cells, the sIgA contents of the duodenum and the jejunum, and the immunoglobulin contents of serum and intestinal mucosa (p<0.05) in broilers exposed to HT. In conclusion, Gln can enhance intestinal immune function in broiler chickens by stimulating T and B lymphocyte proliferation, increasing the number of goblet cells and IEL cells, as well as increasing the content of sIgA and immunoglobulin secretion.

摘要 为探究谷氨酰胺（Glutamine, Gln）对热应激肉鸡淋巴细胞增殖及肠黏膜免疫应答的保护作用，本试验采用完全随机设计，将360只21日龄爱拔益加（Arbor Acres, AA）肉鸡随机分为4组，每组设6个重复单元，每个单元饲养15只肉鸡，试验周期为21天。试验分组如下：无应激基础日粮组（NS组）、热应激基础日粮组（HT组），以及热应激基础日粮分别添加0.5%或1.0%谷氨酰胺的试验组。结果显示，与NS组相比，HT组肉鸡外周血增殖淋巴细胞数量减少，生长性能、中性粒细胞吞噬率与吞噬指数降低，全肠道杯状细胞数量及回肠上皮内淋巴细胞（intraepithelial lymphocyte, IEL）数量下降，十二指肠与空肠分泌型免疫球蛋白A（secretory immunoglobulin A, sIgA）含量降低，血清及肠黏膜免疫球蛋白含量显著降低（p<0.05）。当日粮添加谷氨酰胺后，热应激肉鸡的生长性能，外周血增殖淋巴细胞数量、中性粒细胞吞噬率及吞噬指数，全肠道杯状细胞与回肠上皮内淋巴细胞数量，十二指肠、空肠sIgA含量，以及血清与肠黏膜免疫球蛋白含量均显著提升（p<0.05）。综上，谷氨酰胺可通过刺激T、B淋巴细胞增殖，增加杯状细胞与上皮内淋巴细胞数量，提升sIgA及免疫球蛋白分泌水平，增强肉鸡肠道免疫功能。