Effects of cello-oligosaccharide on intestinal microbiota and epithelial barrier function of weanling pigs

A total of 144 piglets (Duroc x Landrace x Yorkshire; average initial weight of 6.13 kg weaned at 21 +/- 1 d age) were allotted to 4 treatments for 2 wk, each of which had 6 pens with 6 pigs per pen. After the feeding experiment, 6 pigs per treatment were slaughtered to investigate the effects of cello-oligosaccharide (COS) on intestinal microbiota and epithelial barrier function. The COS was added to the basal diet at 0, 1.5, 3.0, and 4.5 g/kg diet at the expense of corn, respectively. Plasma D-lactate, diamine oxidase (DAO), and the Ussing chamber technique were used to determine the intestinal barrier function. 16S rRNA-based methods were used for intestinal microbiota analysis. The results showed that incremental levels of COS had no effect (P > 0.05) on growth performance. Incremental levels of COS increased lactobacilli in jejunal and colonic contents (P < 0.05); decreased Streptococcus suis in jejunal contents (P < 0.05) and S. suis and Escherichia coli in colonic contents (P < 0.05); reduced plasma DAO (linear, P = 0.013, and quadratic, P = 0.037); increased jejunal mucosa DAO (linear, P = 0.003, and quadratic, P = 0.008); decreased fluorescein isothiocyanate dextran 4 kDa flux of jejunum and colon (P < 0.05); and increased transepithelial electrical resistance (TER) in colon (P < 0.05), claudin-1 protein expression in jejunal mucosa (linear, P = 0.001, and quadratic, P = 0.003), and protein expressions of claudin-1 and zonula occludens-1 (ZO-1) in colonic mucosa linearly (P = 0.001 and P = 0.001, respectively) and quadratically (P = 0.001 and P = 0.002, respectively). The results indicated that the improved microbial ecosystem in the presence of COS might contribute to improvement in intestinal barrier function and tight junction proteins. Results also showed that the appropriate dietary COS supplementation level was 3.0 g/kg in weaned pig diets under our trial conditions.