The effects of cereal-derived β-glucans and enzyme supplementation on intestinal microbiota, nutrient digestibility and mineral metabolism in pigs

A complete randomized design experiment was conducted to investigate the effects of β-glucan inclusion (oat intact or purified) and enzyme inclusion on intestinal microbiota, nutrient digestibility and mineral metabolism in pigs. Twenty eight boars (59 kg live weight) were offered one of four dietary treatments T1) oat-based diet T2) oat-based diet with enzymes, T3) wheat-based diet with exogenous (oat-derived) β-glucans and T4) wheat-based diet with exogenous β-glucans and enzymes. The diets were equalised to contain similar β-glucan and arabinoxylan content. The enzyme supplement contained β-glucanase and β-xylanase. Pigs offered diets containing intact β-glucans had higher populations of Bifidobacteria (P < 0.01), and Lactobacilli (P < 0.01) compared to pigs offered diets supplemented with purified β-glucans. Diets containing intact β-glucans had lower digestibility of DM (P < 0.001), OM (P < 0.001), NDF (P < 0.001), N (P < 0.05) and GE (P < 0.001) and a higher total short chain fatty acids (SCFA) concentration in the colon (P < 0.001) compared to pigs supplemented with purified β-glucans. Pigs offered diets containing intact β-glucans had a higher P retention (P < 0.05) and Ca retention (P < 0.05) compared to pigs offered diets supplemented with exogenous β-glucans. Except for faecal nitrogen digestibility, enzyme inclusion had no effect on any variable measured. In conclusion, intact β-glucans increased the populations of Bifidobacteria and Lactobacilli, as well as increasing phosphorus retention compared to pigs supplemented with purified β-glucans.