In Vitro Gut Microbiome Response to Carbohydrate Supplementation is Minimally Affected by a Sudden Change in Diet

Abstract

Background: Interactions between diet, stress and the gut microbiome are of interest as a means to modulate health and performance. Here, in vitro fermentation was used to explore the effects of a sudden change in diet, 21 days sole sustenance on the Meal, Ready-to-Eat (MRE) U.S. military combat ration, on inter-species competition and functional potential of the human gut microbiota. Human fecal samples collected before and after MRE intervention or consuming a habitual diet (HAB) were introduced to nutrient-rich media supplemented with starch for in vitro fermentation under ascending colon conditions. 16S rRNA amplicon and Whole Genome Sequencing (WGS) were used to measure community composition and functional potential. Specific statistical analyses were implemented to detect changes in relative abundance from taxa, genes and pathways.Results: Differential changes in relative abundance of five taxa, Dorea spp., Akkermansia muciniphila, Prevotella spp., Desulfovibrio spp., and Dialister spp., and four Carbohydrate-Active Enzymes, specifically GH13_14, over the 24 h fermentation were observed as a function of the diet intervention and correlated to specific taxa of interest. Conclusions: These findings suggest that consuming MRE for 21 days minimally effects changes in gut microbiota structure in response to carbohydrate, but may induce alterations in metabolic capacity. Additionally, these findings demonstrate the potential of starch as a candidate supplemental strategy to functionally modulate specific gut commensals during stress-induced states.

In Vitro Fermentation Evaluation of Engineered Sense and Respond Probiotics in Polymicrobial Communities

“…33−37 Additionally, the technique has been employed for understanding functional metabolic changes within the human gut microbiome during acute stress states and exposure of regionally specific microbiota composition and microbial activity in luminal and mucosal domains. 38,39 At relevant use of these systems is as an in vitro-based test bed for engineered organisms that employs a systematic approach to increasing metabolic competition using simplified, defined communities to assess engineered probiotic persistence, functional output, and impact on commensal organisms. 40 Defined synthetic communities offer less complexity than fecal inoculum but have been used to mimic complex environments to conduct studies not feasible using in vivo methods.…”