Evaluation the Viability of the Saccharomyces Boulardii Bld-3 and its Influence on the Colonic Microbiota Composition by SHIME

During this study the viability of Saccharomyces Boulardii Bld-3 during passage through the upper GIT under fed and fasted conditions was evaluated. For this purpose, a Simulator of the Human Intestinal Microbial Ecosystem (SHIME®) was used, which allows to re-create the physiological conditions that are representative of the human GIT. Furthermore, the aim of this study was also to study the modulatory effect of the Saccharomyces Boulardii Bld-3 on the colonic microbiota composition and activity after passage of the strain through the fed or fasted upper GIT or when delivered directly to the colon. For this purpose, four different types of short-term colonic batch experiments were performed that simulate the colonic fermentation process. The Saccharomyces Boulardii Bld-3 completely survived the stomach phase of the fed upper GIT, characterized with a long residence time and intermediate pH conditions and was capable to cope with the high concentrations of bile acids in the fed small intestine. Subtle effects were observed on SCFA, BCFA and ethanol production with a consistent significantly moderately higher acetate production in the present of Saccharomyces Boulardii Bld-3. This was also confirmed through determination of the concentrations of lactobacilli, bifidobacterial, and firmicutes at the end of the colonic incubations. Indeed, no statistical significant differences were observed between the control experiments and those performed with the Saccharomyces Boulardii Bld-3. Only higher concentrations of Bacteroidetes were present at the end of the experiments to which the Saccharomyces Boulardii Bld-3 was added (highest effect after fed and fasted upper GIT passage). This could explain the higher concentrations of BCFA during the colonic incubations with the Saccharomyces Boulardii Bld-3 since several members of the Bacteroidetes are known proteolytic bacteria.