Effects of alginate oligosaccharide on the growth performance, antioxidant capacity and intestinal digestion-absorption function in weaned pigs

Alginate oligosaccharide (AOS), a depolymerisation product of alginic acid polysaccharides of seaweed by alginate lyases, holds great potential as a novel feed supplement in swine production. This study conducted two trials to evaluate the effects of AOS supplementation on the growth performance, antioxidant capacity, serum hormone levels and intestinal digestion-absorption function in weaned pigs. In trial 1, 200 weaned pigs were allotted to four groups and fed a basal diet (control group) or a basal diet containing 50, 100 and 200 mg/kg AOS, respectively. Supplementation with 100 or 200 mg/kg AOS for 2 weeks significantly increased (P < 0.05) the average daily body weight gain of the pigs compared to the control group. In trial 2, 24 weaned pigs were allotted to a control group (fed with a basal diet) or an AOS group (basal diet containing 100 mg/kg AOS). On days 11-14, fresh faecal samples were collected from eight randomly selected pigs in each treatment, to evaluate apparent digestibility of nutrients. On the morning of day 15, the serum and intestinal mucosal samples were collected from the same selected pigs. Experimental results revealed that AOS effectively promoted antioxidant defence properties, through enhancing serum catalase activity and glutathione content. Serum hormone levels, including insulin and insulin-like growth factor-1, were improved (P < 0.05) by AOS supplementation. Compared to the control group, AOS supplementation elevated (P < 0.05) the nutrient digestibility (crude protein, ash and fat), as well as the maltase and sucrase activities, in the duodenal and jejunal mucosa. Furthermore, AOS supplementation increased (P < 0.05) the Na+/glucose co-transporter 1 (SGLT1) and divalent metal transporter 1 (DMT1) transcriptions in the jejunal mucosa. Altogether, dietary AOS inclusion can stimulate weaned pig growth, validating AOS as a valid feed supplement in the pig industry.