CARBOHYDRATE SOURCE AND BIFIDOBACTERIA INFLUENCE THE GROWTH OF CLOSTRIDIUM-PERFRINGENS IN-VIVO AND IN-VITRO

The purpose of this study was to test the effects of administering bif idobacteria with either 2% frcutooligosaccharide (FOS), 2% wheat bran oligosaccharide (WBOS), 2% soybean oligosaccharide (SBOS) or no added oligosaccharide (control) on cecal populations of bifidobacteria and C . perfringens, a potential pathogen and normal inhabitant of the mamma lian colon, in the rat. Rats were randomly assigned to one of four tre atment groups: basal diet + 1 ml daily gavage of skim milk containing 10(8) bifidobacteria, 2% FOS + bifidobacteria, 2% SBOS + bifidobacteri a or 2% WBOS + bifidobacteria. The rats were fed the diets for 4 wk, a fter which cecal concentrations of bifidobacteria and C. perfringens w ere assessed. WBOS and SBOS feeding resulted in higher concentrations of bifidobacteria and C. perfringens relative to FOS-feeding or contro l. However, no differences in either bifidobacteria or C. perfringens were detected between control and FOS groups. Parallel to this animal study, in vitro competition experiments with bifidobacteria and C. per fringens were performed in growth media containing either glucose, FOS or WBOS as the primary carbon source. The concentrations of bifidobac teria and C. perfringens were determined at each hour for 10 h and spe cific growth rates (mu) were calculated. The lr for C. perfringens, co -cultured with bifidobacteria in glucose-based or WBOS-based media was significantly decreased relative to C. perfringens alone. However, no significant difference was found between the mu for C. perfringens co -cultured in FOS-based media with bifidobacteria and the C. perfringen s grown alone in FOS-based media. These findings indicate that differe nt oligosaccharides have differential effects on the populations of bi fidobacteria and C. perfringens in vivo and that certain oligosacchari des may potentiate an inhibitory action of bifidobacteria against C. p erfringens. (C) 1998 Elsevier Science Inc.