不同蛋氨酸水平对人肠道菌群影响的体外评价研究OA

Methionine is the only essential sulfur-containing amino acid in humans,and its intake varies considerably among populations with different dietary patterns;however,the impact of different methionine intake levels on the human gut microbiota remains unknown.This study aimed to investigate the effects of different methionine levels on the human gut microbiota using an in vitro simulated anaerobic fermentation method,in which 16S rDNA high-throughput sequencing was used to detect the composition of the gut microbiota,gas chromatography to determine the content of short-chain fatty acids(SCFAs),and methylene blue spectrophotometry to determine the content of hydrogen sulfide(H2S).The results showed that after in vitro fermentation,the fermentation broth was mainly composed of Firmicutes,Proteobacteria,and Bacteroidota at the phylum level,and at the genus level,with the increase in methionine level,the abundance of H2S-producing bacteria(Desulfovibrio and Bilophila)gradually increased,while the abundance of SCFA-producing bacteria(Lachnoclostridium,Bacteroides and Parabacteroides)gradually decreased,and the abundance of harmful bacteria(Escherichia-Shigella,Klebsiella,and Dialister)also gradually increased;in addition,the concentration of H2S in the fermentation broth increased gradually with the increase in methionine level,while the concentration of SCFAs decreased gradually,and correlation analysis revealed that H2S concentration was extremely significantly negatively correlated with SCFAs concentration,positively correlated with the abundance of harmful bacteria,and negatively correlated with the abundance of beneficial bacteria,while SCFAs concentration was negatively correlated with the abundance of harmful bacteria and positively correlated with the abundance of beneficial bacteria.Therefore,moderate reduction of methionine intake may have the potential to improve human intestinal microbiota composition and internal environment health,and this study provides a theoretical basis for establishing the association between dietary methionine intake and human intestinal homeostasis,as well as new scientific evidence for improving human gut microbiota and intestinal health through precision methionine nutrition.