Dietary supplementation with mannanoligosaccharides and β glucans in growing rabbits. 2 Gut Barrier and intestinal microbiota after weaning

The aim of this work was to determine the effect of yeast mannanoligosaccharides (MOS; Actigen, Alltech) and yeast β-glucans on gut barrier and intestinal microbiota in rabbits. A control diet (C) was formulated to meet rabbit growth requirements. G1 and G2 diets were obtained by supplementing C diet with β-glucans from Saccharomyces cerevisiae (100 and 200 mg/kg respectively), M1 and M2 diets were supplemented with mannanoligosaccharides (Actigen, Alltech) (400 and 800 mg /kg respectively), and GM diet was supplemented with 100 mg/kg of β-glucans + 400 mg/kg of MOS. Ninety six rabbits weaned at 32 days of age were randomly assigned to the six experimental diets and slaughtered 15 days after weaning. The type of diet did not affect villus length and goblet cell counts, but crypt depth was reduced at the highest levels of MOS and β-glucans supplementation. Both MOS and β-glucans increased specific sucrose activity (P = 0.001) and soluble protein concentration (P < 0.05) in jejunal mucosa; they also modified ileal and caecal microbiota and modulated the immune response. Compared with the control diet, the supplementation with 200 mg/kg of β-glucans (G2) and 800 mg/kg of MOS (M2) reduced the expression of iNOS in ileum. Rabbits fed the M2 diet showed also the lowest mRNA abundance of IL6. In appendix, rabbits fed G2 showed increased IL6 expression and those fed the M2 reduced the expression of INFγ. In conclusion, MOS and β-glucans changed intestinal microbiota and modulated the immune response by reducing the expression of some pro-inflammatory cytokines in ileum and caecum of weaned rabbits.