The effect of glucagon-like peptide 2 injection on performance, small intestinal morphology, and nutrient transporter expression of stressed broiler chickens

Abstract

An experiment was conducted to determine the effect of injecting glucagon-like peptide 2 (GLP-2) on the small intestinal weight, morphology, and nutrient transporter expression in pharmacologically stressed broiler chickens. A total of 144 seven-day-old birds were fed either a basal diet (CTRL) or a basal diet plus 30 mg of corticosterone (CORT)/kg of diet for a total of 14 d. Half of the birds from each group were injected daily with GLP-2 (6.7 nmol/kg of BW) or saline for 14 d. The average final BW, ADG, ADFI, and the ratio of feed intake to weight gain (F:G) was recorded over 21 d for the 4 groups of 36 birds, namely CTRL + saline, CTRL + GLP-2, CORT + saline, and CORT + GLP-2. In addition, the absolute and relative small intestinal weight, villus height (VH), and crypt depth (CD) of the duodenum and jejunum, as well as the abundance of sodium and glucose co-transporter 1 (SGLT-1), vitamin D-dependent calcium-binding protein-28,000 molecular weight (CaBP-D28k), and peptide transporter 1 (PepT-1) mRNA in the duodenum and of liver fatty acid-binding protein (L-FABP) mRNA in the jejunum. The total DNA, RNA, and protein content in small intestinal mucosa were also determined. The results showed that CORT administration significantly lowered average final BW, ADG, ADFI, absolute small intestinal weight, VH, and CD of duodenum and jejunum (P < 0.05) while increasing the relative small intestinal weight, F:G, relative abundance of SGLT-1, CaBP-D28k, PepT-1, and L-FABP mRNA (P < 0.05). Glucagon-like peptide 2 injection increased the average final BW, ADG, VH, and CD in duodenum and jejunum and relative abundance of SGLT-1, CaBP-28k, PepT1, and PepT1 mRNA of broiler chickens, respectively (P < 0.05), and decreased F:G (P < 0.05). In chickens fed basal diet plus CORT, injecting GLP-2 decreased F:G (P < 0.05); increased VH and CD of duodenum and CD of jejunum; and increased relative abundance of SGLT-1, CaBP-D28k, PepT-1, and L-FABP mRNA, RNA, and total protein content in small intestine compared with the injection of saline (P < 0.05). In birds fed the basal diet, GLP-2 injection decreased F:G (P < 0.05) and increased final BW, ADG, small bowel weight, CD of jejunum, and relative abundance of CaBP-D28k and PepT-1 mRNA compared with injecting saline (P < 0.05). In conclusion, GLP-2 injection reversed the negative effect of stress on the weight and morphology and the absorptive function of small bowel of broiler chickens. Glucagon-like peptide 2 injection also had a positive effect on the growth performance of healthy broiler chickens.

Effects of Xylo-Oligosaccharides on Broiler Chicken Performance and Microbiota

“…Its receptor (GLP-2R) is localized on distinct subpopulations of gut endocrine cells in the stomach, small intestine, and colon but also on subepithelial myofibroblasts (67,68). Hu et al showed a beneficial effect of intravenous GLP-2 injection in broilers on growth performance, intestinal morphology, villus height, and crypt cell proliferation (69).…”

Hormones and Metabolism in Poultry

“…• Decreased skeletal muscle weight (Yuan et al, 2008;Song et al, 2011) • Increased protein degradation as indicated by increases in the concentrations of 3-methyl histidine in both pectoralis and femoris muscles (Dong et al, 2007) • Increases muscle proteolysis (Gao et al, 2008) • Reduced skeletal protein synthesis as indicated by the RNA:protein ratio (Dong et al, 2007) Decreasing the growth of the small intestine in chickens although the effect is of a small magnitude than that with overall growth as weight of the small intestine relative to body weight is increased (Hu et al, 2010) • Increases expression of myostatin (Song et al, 2011).…”

“…• Increasing expression sodium and glucose co-transporter 1 (SGLT-1 vitamin Ddependent calcium-binding protein-28,000 molecular weight (CaBP-D28k), and peptide transporter 1 (PepT-1) mRNA in the duodenum (Hu et al, 2010) • Increasing expression of genes related to obesity in the chicken hypothalamus including brain-derived neurotrophic factor (BDNF), neuropeptide Y and agouti-related protein (AGRP) (Byerly et al, 2009) • Depressing adenosine deaminase activity in all regions of the chicken gastro-intestinal tract except the proventriculus (Bhattacharjee et al, 2009).…”

“…Glucocorticoids including the endogenous avian steroid, corticosterone, and the synthetic dexamethasone depress growth in chickens (Li et al, 2009;Hu et al, 2010;Song et al, 2011).…”

“…• Depressing duodenal and jejunal villus height and crypt depth (Hu et al, 2010) Corticosterone plays the pivotal role in inducing functioning somatotropes during late embryonic development (Dean and Porter, 1999;Porter et al, 2001). …”