Effects of isomalto-oligosaccharides as potential prebiotics on performance, immune function and gut microbiota in weaned pigs

This study evaluated the effects of isomalto-oligosaccharides (IMO) in diet on the performance, fecal score, serum immunity, intestinal morphology, volatile fatty acid (VFA) concentrations and gut microbiota in cecum of weaned pigs. In a 28-day experiment, 72 healthy crossbred (Duroc × Landrace × Large White) weaned pigs with an average body weight of 8.76 ± 1.04 kg were assigned into 2 treatments with 6 replicate pens per treatment (3 barrows and 3 gilts per pen) according to sex and weight in a randomized complete block design. The dietary treatments consisted of a corn-soybean meal basal diet (CTR) or the basal diet supplemented with 6 g/kg IMO at the expense of corn. Compared with CTR, IMO tended to increase average daily gain (ADG) during days 14 to 28 (P = 0.06) and days 0 to 28 (P = 0.07) rather than during days 0 to 14 for weaned pigs. The fecal score was lower for pigs fed IMO than CTR overall or during the first 2 weeks (P < 0.05). On day 28, IMO increased the apparent total track digestibility (ATTD) of dry matter, organic matter and gross energy (P < 0.05), and tended to increase the ATTD of crude protein compared with CTR (P = 0.06). On day 14, IMO decreased (P < 0.05) malondialdehyde (MDA) level, increased (P < 0.05) glutathione peroxidase (GSH-PX), catalase (CAT) and immunoglobulin G (IgG) levels, and tended to increase (P = 0.06) superoxide dismutase (SOD) level in serum. The villus height of the ileum and the total VFA concentrations in cecum and colon were greater in pigs fed IMO than CTR (P < 0.05). Gene sequencing analysis of 16 s rDNA revealed that IMO could regulate the gut microbiota according to unweighted principal coordinate analysis (PCoA). Linear discriminant analysis effect size (LEfSe) analyses showed many different taxa between CTR and IMO, of which the abundance of relative beneficial bacteria including Streptococcaceae and Collinsella was increased by IMO supplementation (P < 0.05). Overall, IMO supplementation has positive effects on performance and serum immunity, and could regulate gut microbiota in cecum of weaned pigs. Accordingly, IMO could be potential prebiotics to improve performance by strengthening immune function and intestinal health in weaned pigs.