New insights into the role of chitosan oligosaccharide in enhancing growth performance, antioxidant capacity, immunity and intestinal development of weaned pigs

Abstract

Chitosan oligosaccharide (COS), an oligomer of D-glucosamine, is a vital growth stimulant in the pig industry. However, the mechanisms by which COS mediates pig growth are not fully understood. Therefore, we further investigated how COS supplementation affects pig growth. A total of 32 Landrace × Yorkshire weaned pigs were randomly divided into a control group (basal diet without COS supplementation) and a COS group (100 mg COS per kg basal diet). The pigs that ingested COS for 21 days were associated with a higher (P < 0.05) average daily body weight gain compared to those in the control group. Relative to the control group, the apparent digestibility of crude protein, ash, fat, dry matter and gross energy were markedly elevated (P < 0.05) upon COS supplementation. COS supplementation not only increased (P < 0.05) the activities of superoxide dismutase, catalase and total antioxidant capacity but also elevated (P < 0.05) interleukin-6, tumour necrosis factor-α and immunoglobulin G concentrations in the serum. Moreover, the serum malondialdehyde concentration was decreased (P < 0.05) 26.59% by COS ingestion. COS supplementation also significantly enhanced (P < 0.05) secretory immunoglobulin A content, villus height and digestive enzyme activities (maltase, lactase and sucrase) in the small intestine. Intriguingly, dietary COS supplementation up-regulated (P < 0.05) the tight junction protein claudin-1 (CLDN-1) and occludin (OCLN) mRNA abundance, as well as the Na⁺–glucose co-transporter 1 (SGLT1) mRNA abundance in the jejunum. Importantly, COS not only increased (P < 0.05) the Bifidobacterium populations in the ileum but also decreased (P < 0.05) the total bacteria and Escherichia coli populations in the caecum and colon. Together, these results suggest that COS supplementation can accelerate weaned pig growth through enhancing antioxidant and immune properties, as well as intestinal development.