Oat arabinoxylan promoted <i>Lactobacillus gasseri</i> to alleviate metabolic disorders in high-fat diet-induced obese mice

Arabinoxylan (AX) has been found to improve an imbalanced gut microbiota. <i>Lactobacillus gasseri</i> is a beneficial endogenous bacterium that has been shown to have several health benefits in the human gut, particularly its lipid-lowering activity. However, it is not known whether AX can promote the action of <i>L. gasseri</i>. The results of <i>in vitro</i> experiments showed that AX promoted biofilm formation in <i>L. gasseri</i>, its acid and bile salt resistance could be enhanced, and enabled better colonization of <i>L. gasseri</i> in the intestinal tract of mice. <i>In vivo</i> experiments showed that the AX + <i>L. gasseri</i> group could effectively ameliorate weight gain and fat accumulation in high-fat diet-induced obese mice, and the <i>L. gasseri</i> group or AX + <i>L. gasseri</i> alleviated liver injury in mice. 16S rRNA sequencing showed that <i>L. gasseri</i> can colonize the mice intestine and AX + <i>L. gasseri</i> can ameliorate gut microbiota dysbiosis in obese mice by increasing <i>Lactobacillus</i> spp. and Coriobacteriaceae_UCG-002, and decreasing Peptococcaceae. In addition, metabolomics results indicated that the <i>L. gasseri</i> group and the AX + <i>L. gasseri</i> group could alleviate metabolic disorders by decreasing the levels of <i>L</i>-phenylalanine, <i>L</i>-tyrosine, kynurenine acid, and arachidonic acid in obese mice. The effect of AX + <i>L. gasseri</i> group was better than that of the <i>L. gasseri</i> group, suggesting that AX promotes the lipid-lowering activity of <i>L. gasseri</i>, and the mechanism may be due to the activation of retrograde endocannabinoid signaling. AX can be used as a functional food ingredient to potentially alleviate obesity and metabolic syndrome.