The effects of probiotic, prebiotic and synbiotic diets containing Bacillus coagulans and inulin on rat intestinal microbiota

An in vivo experiment was conducted to study the effects of probiotic Bacillus coagulans spores، with and without prebiotic، inulin، on gastrointestinal (GI) microbiota of healthy rats and its potentiality to survive in the GI tract. Forty-eight male Wistar rats were randomly divided into four groups (n=12) and fed as follows: standard diet (control)، standard diet supplied with 5% w/w long chain inulin (prebiotic)، standard diet with 109/day spores of B. coagulans by orogastric gavage (probiotic)، and standard diet with 5% w/w long chain inulin and 109 spores/day of B. coagulans by orogastric gavage (synbiotic). Rats were fed the diets for 30 days. At day 10، 20 and 30 of experiment، 24 h post administration، four rats from each group were randomly selected and after faecal collection were sacrificed. Small intestine، cecum، and colon were excised from each rat and used for microbial analysis. Administration of synbiotic and probiotic diets led to a significant (P<0. 05) increment in lactic acid bacteria (LAB)، total aerobic and total anaerobic population compared the prebiotic and control diets. A significant decrease in Enterobacteriaceae counts of varioussegments of GI tract (except small intestine) in synbiotic، probiotic and prebiotic fed groups were also seen. The obvious decline in spores count through passing GI tract and high surviving spore counts in faecal samples showed that spores are not a normal resident of GI microbiota and affect intestinal microbiota by temporary proliferation. In conclusion، the present study clearly showed probiotic B. coagulans was efficient in beneficially modulating GI microbiota and considering transitional characteristics of B. coagulans، daily consumption of probiotic products is necessary for any long-term effect.