The regulatory effects of butyrylated starch on gut microbiota and metabolites during in vitro fermentation: advantages over exogenous butyrate and resistant starch

Butyrylated normal maize starch (BNMS) is a butyrate-carrying and resistant starch (RS). BNMS is fermented by the gut microbiota to produce large amounts of short-chain fatty acids (SCFAs), particularly butyrate, which are beneficial for intestinal health. However, the effects of BNMS on gut microbiota and metabolites, and its advantages over exogenous butyrate and RS, are unclear. The specific effects of BNMS were investigated via in vitro fermentation using sodium butyrate (SB) and high-amylose maize starch (HAMS) as controls. Compared to SB and HAMS, BNMS enhanced gas production, lowered pH, and produced numerous SCFAs. Additionally, BNMS effectively stimulated beneficial bacteria proliferation, including Coprococcus , Faecalibacterium , Megamonas , Collinsella , Blautia , and Bifidobacterium , and suppressed harmful bacteria proliferation, including Escherichia-shigella and Desulfovibrio , resulting in a healthier colony structure. Similarly, BNMS modulated many amino acids, neurotransmitters, vitamins, sphingolipids, carbohydrates, hormones levels, and multiple metabolic pathways, including arginine and proline metabolism, tryptophan metabolism, synaptic vesicle cycle, sphingolipid metabolism, riboflavin metabolism, amino sugar and nucleotide sugar metabolism, and steroid hormone biosynthesis. Overall, BNMS positively affected gut microbiota and metabolites, exhibiting advantages over exogenous butyrate and RS. These results provide some theoretical basis for the BNMS development and application as a functional food.