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.

ABSTRACT The aim of this study was to investigate the effects of glutamine (Gln) on the intestinal mucosal structure and immune cells of broilers infected with Salmonella Enteritidis. 160 1-d-old commercial Arbor Acres (AA) broilers were randomly selected to receive one of four treatments, each of which had 5 replicates. Each replicate consisted of 8 chicks subjected to a 21-d feeding trial. Group I served as the unchallenged (CON). All birds in groups II (SCC) - IV were challenged with 2.0 × 104 CFU/mL of S. Enteritidis. The birds in groups III and IV were treated with 0.5% and 1.0% Gln. The results showed that S. Enteritidis infection led to a decrease in the relative length and weight, villus height:crypt depth (VH:CD) of the jejunum and ileum, the number of intraepithelial lymphocyte cells, and number of goblet cells and an increase in the number of mast goblet cells compared with the measurements of these parameters in the CON group (p<0.05). In addition, the Gln groups had increased relative length and weight, VH:CD of the jejunum and ileum, numbers of intraepithelial lymphocyte cells, and numbers of goblet cells and decreased crypt depth in the jejunum and ileum and numbers of mast goblet cells compared with the measurements of these parameters in the SCC group (p<0.05). It was concluded that Gln added to broiler diets can effectively alleviate the intestinal mucosal damage caused by S. Enteritidis infection and improve its normal defense barrier function.

ABSTRACT The aim was to investigate the effect of glutamine (Gln) on broilers challenged with Salmonella Enteritidis. 240 1-day-old birds were divided into four groups in a completely randomized design, each of which included 6 replicates with 10 birds per replicate. Group I served as the unchallenged, untreated control (CON). All birds in groups II (SCC) - IV were challenged with 2.0 × 104 CFU/mL of S. Enteritidis. Birds in group III and IV were treated with 0.5% (Gln 1) and 1.0% (Gln 2), respectively, of Gln. The results indicated that S. Enteritidis infection led to a decrease in the average body weight at d 7, 14, and 21 (p<0.05). Chickens fed the Gln showed improved average body weights in comparison with the SCC group (p<0.05). At d 4, 7, 14, and 21, the Gln groups increased digestive enzyme (trypsin, lipase and amylase (except the amylase activity of jejunum at d 14 and d 21)) activities in the intestine (p<0.05), superoxide dismutase (SOD) (at d 14 jejunum; except at d 4, ileum) and catalase (CAT) (at d 4, and d 21, jejunum; d 4, ileum) activity in the serum (except at d 14) and intestinal mucosa (p<0.05), and the mRNA expression of SOD, CAT and nuclear respiratory factor 2 (Nrf2) of the intestinal mucosa compared with the SCC group (p<0.05). These results suggest that Gln as a feed additive could be effective for reducing the detrimental effects of S. Enteritidis infection of broilers.