Chitosan oligosaccharide improves intestinal function by promoting intestinal development, alleviating intestinal inflammatory response, and enhancing antioxidant capacity in broilers aged d 1 to 14

This study was conducted to investigate the effects of chitosan oligosaccharide (COS) supplementation on intestinal development and functions, inflammatory response, antioxidant capacity and the related signaling pathways in broilers aged d 1 to 14. A total of 240 one-day old male Arbor Acres broilers (40.47 +/- 0.30 g) were randomly allotted to 4 groups, and each group consisted of 6 replicate pens with 10 broilers per replicate. Broilers fed a basal diet supplementation with COS at 0 (CON group), 200 (COS200 group), 400 (COS400 group), and 800 mg/kg (COS800 group) for 14 d, respectively. Broilers in the COS supplementation groups had no significant effects on growth performance. Compared to the CON group, dietary COS supplementation increased (P < 0.05) the relative weight of duodenum, jejunal lipase activity, duodenal and ileal villus surface area, and lower (P < 0.05) ileal amylase and alkaline phosphatase activity, and crypt depth. The expression level of duodenal glucose transporter 1 (GLUT1), Na+-glucose cotransporter 1 (SGLT1), peptide transporter 1 (PepT1), occludin, zonula occludens-1 (ZO-1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and interleukin-10 (IL-10), jejunal SGLT1, PepT1, occludin, tumor necrosis factor-alpha (TNF-alpha), and ileal SGLT1, PepT1, and fatty acid binding protein 1 (FABP1) was upregulated by COS. However, the expression level of duodenal FABP1 and TNF-alpha, jejunal GLUT1, ZO-1, TLR4, MyD88, nuclear factor kappa-B p65 (NF-kappa B p65), and IL-1 beta, and ileal GLUT1, NF-kappa B p65, and IL-1 beta was downregulated by COS. Furthermore, dietary COS supplementation increased duodenal catalase (CAT), glutathione peroxidase (GSH-Px), and total superoxide dismutase (T-SOD) activity, jejunal CAT and T-SOD activity, upregulated the expression level of duodenal nuclear factor-erythroid 2-related factor 2 (Nrf2), CAT, glutathione peroxidase 1 (GPX1), and copper and zinc superoxide dismutase (Cu/Zn SOD), jejunal CAT, and ileal Nrf2, CAT, and GPX1. These results suggested that COS could promote intestinal development and functions in broilers aged d 1 to 14, which might be mediated by alleviating intestinal inflammatory response and enhancing antioxidant capacity.