Modulation of gut flore by dietary fibers from Pyrus bretschneideri Rehd.: Evaluation of fermentation characteristics using a colonic in vitro fermentation model.

[Display omitted] • Four carbon sources derived from Pyrus bretschneideri Rehd. affect the growth of microorganisms associated with obesity. • Different gut microorganisms are correlated with short-chain fatty acids. • Anaerostipes used lactic acid and acetic acid as substrates to produce butyric acid. Nutrients such as dietary fiber in Pyrus bretschneideri Rehd. (PBR), which is mainly produced on the Tibetan Plateau, can be used as a fermentable carbon source for microorganisms. However, the mechanisms by which different carbon sources interact with microorganisms and their fermentation metabolites are not clear. In this study, four different carbon sources extracted from PBR were used to explore the effect of carbon source type on gut flora (GF) and the metabolites thereof through an in vitro simulated colonic fermentation model. The results showed a differentiation of the type of carbon source on the species composition and structure of GF, as well as on the production of metabolites during in vitro fermentation. Correlations between some microbial taxa and their metabolites were also revealed, such as Subdoligranulum and acetic acid, Collinsella and propionic acid, and Fusicatenibacter and butyric acid showing significant positive correlations. Notably, a cross-feeding pathway was clarified: Anaerostipes uses lactic acid and acetic acid as substrates to produce butyric acid. Overall, this study provided insight into the effects of different carbon sources from PBR as fermentation substrates on GF growth and metabolism, which could provide a basis for exploring the relationship between carbon source types, GF and their metabolites, and promote the integrated development of PBR resources in Qinghai Province. [ABSTRACT FROM AUTHOR]