The Rowett Institute, University of Aberdeen, Aberdeen, UK.
Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile.
Environ Microbiol. 2023 Aug;25(8):1484-1504. doi: 10.1111/1462-2920.16368. Epub 2023 Mar 28.
Dietary fibre is a major energy source for the human gut microbiota, but it is unclear to what extent the fibre source and complexity affect microbial growth and metabolite production. Cell wall material and pectin were extracted from five different dicotyledon plant sources, apples, beet leaves, beetroots, carrots and kale, and compositional analysis revealed differences in the monosaccharide composition. Human faecal batch incubations were conducted with 14 different substrates, including the plant extracts, wheat bran and commercially available carbohydrates. Microbial activity was determined for up to 72 h by measuring gas and fermentation acid production, total bacteria (by qPCR) and microbial community composition by 16S rRNA amplicon sequencing. The more complex substrates gave rise to more microbiota variation compared with the pectins. The comparison of different plant organs showed that the leaves (beet leaf and kale) and roots (carrot and beetroot) did not give rise to similar bacterial communities. Rather, the compositional features of the plants, such as high arabinan levels in beet and high galactan levels in carrot, appear to be major predictors of bacterial enrichment on the substrates. Thus, in-depth knowledge on dietary fibre composition should aid the design of diets focused on optimizing the microbiota.
膳食纤维是人类肠道微生物群的主要能量来源，但膳食纤维的来源和复杂性对微生物生长和代谢产物产生的影响程度尚不清楚。从五种不同的双子叶植物源（苹果、甜菜叶、甜菜根、胡萝卜和羽衣甘蓝）中提取细胞壁物质和果胶，并进行组成分析，揭示了单糖组成的差异。用 14 种不同的底物（包括植物提取物、麦麸和市售碳水化合物）进行人体粪便批量孵育。通过测量气体和发酵酸的产生、总细菌（通过 qPCR）和 16S rRNA 扩增子测序来测定微生物群落组成，在长达 72 小时的时间内测定微生物活性。与果胶相比，更复杂的底物引起了更多的微生物多样性变化。不同植物器官的比较表明，叶子（甜菜叶和羽衣甘蓝）和根（胡萝卜和甜菜根）不会产生相似的细菌群落。相反，植物的组成特征，如甜菜中的高阿拉伯聚糖水平和胡萝卜中的高半乳聚糖水平，似乎是细菌在底物上富集的主要预测因子。因此，深入了解膳食纤维的组成应该有助于设计旨在优化微生物群的饮食。
