[Effects of different carbohydrates on the simulation of human intestinal bacterial flora with in vitro culture]

Effects of Different Feeding Methods on the Structure, Metabolism, and Gas Production of Infant and Toddler Intestinal Flora and Their Mechanisms

In this study, we evaluated the effects of different feeding methods on the characteristics of intestinal flora and gas production in infants and toddlers by using an in vitro simulated intestinal microecology fermentation and organoid model. We found that the feeding method influences intestinal gas and fecal ammonia production in infants and toddlers. Supplementation with milk powder for infants in the late lactation period could promote the proliferation of beneficial bacteria, including Bifidobacteria. Intestinal flora gas production in a culture medium supplemented with fucosyllactose (2′-FL) was significantly lower than that in media containing other carbon sources. In conclusion, 2′-FL may reduce gas production in infant and toddler guts through two mechanisms: first, it cannot be used by harmful intestinal bacteria to produce gas; second, it can inhibit intestinal mucosa colonization by harmful bacteria by regulating the expression of intestinal epithelial pathogenic genes/signaling pathways, thus reducing the proliferation of gas-producing harmful bacteria in the gut.

Effect of Lactobacillus gasseri PA3 on gut microbiota in an in vitro colonic simulation

It has been reported that Lactobacillus gasseri PA3 has an ability to absorb exogenous purines in the intestine to reduce a risk of gout and hyperuricemia. However, influences of this strain on gut microbiota and their metabolisms remain unclear. Herein, we aimed to investigate the effect of L. gasseri PA3 on microbiota composition and metabolisms. L. gasseri PA3 was isolated from yogurt and supplemented into a single-stage colonic fermentation in a culture volume of 30 ml and subjected to in vitro colonic simulation for 8 days. Microbiota composition was determined with 16S rRNA (V3 + V4) sequencing, and their metabolisms were predicted by PICRUSt. Short-chain fatty acids were measured by GC-MS. We found that L. gasseri PA3 reduced the diversity of microbiota, increased the relative abundances of Lactobacillus (73.5%) and Escherichia (36.5%), and decreased Bacterioides and Phascolarctobacterium. Total amount of short-chain fatty acids was found to decline. Fundamental metabolisms, especially nucleotide, was significantly higher after intervention with L. gasseri PA3, but the purine metabolism was lower, which means that PA3 might reduce uric acid concentrations by weakening purine metabolism. Our results indicated that L. gasseri PA3 can survive and play a role in the ascending colon environment. Therefore, the evaluation of the effect of L. gasseri PA3 on intestinal microbes and their metabolisms has great guiding significance for the development of treatment to prevent gout.