Modulation of Rat Cecal Microbiota by the Administration of Raffinose and Encapsulated Bifidobacterium breve

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 To investigate the effects of raffinose and encapsulated Bifidobacterium breve JCM 1192 cells administration on rat cecal microbiota, as a preclinical synbiotic study, groups of male WKAH/Hkm Slc rats were fed for three weeks with four different test diets: basal diet (BD), BD supplemented with raffinose (RAF), BD supplemented with encapsulated B. breve (CB), and BD supplemented with both raffinose and encapsulated B. breve (RCB). The bacterial populations of cecal samples were determined by fluorescence in situ hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP). B. breve cells were detected only in the RCB diet group and represented about 6.3% of the total cells as determined by FISH analysis. The presence of B. breve was also detected only in the RCB group by T-RFLP analysis. This was in contrast to the CB group in which no B. breve signals were detected by either FISH or T-RFLP. Increase of the population of Bifidobacterium animalis, an indigenous Bifidobacterium of the rat, was observed in the RAF and RCB groups. Principal component analysis of T-RFLP results revealed significant alterations in the bacterial populations of rats in the RAF and RCB groups; the population in the CB group was similar to that of the control (BD) group. To the best of our knowledge, these results provide the first clear picture of the changes of rat cecal microbiota in response to the synbiotic administration.