ObjectivesTo investigate the correlation between a single administration of Lactobacillus acidophilus 5 (LA5)–a potent lactic acid-producing bacterium previously been shown to attenuate obesity–vs microbiota alteration. MethodsLA5 was administered daily together at 1 × 108 colonies forming unit with a high-fat diet (HFD) for 8 weeks in male C57BL/6 mice. Fecal samples with bowel tissues were collected to measure Lactobacillus spp. and Akkermansia spp. Gut permeability, lipid profiles, obesity-induced liver damage, and serum cytokines were also measured. In vitro experiment was conducted by using the HepG2 hepatocyte cell-line with palmitic acid and/or endotoxin. ResultsLA5 attenuated obesity in mice as demonstrated by weight reduction, regional fat accumulation, lipidemia, liver injury, gut permeability defect, endotoxemia, and serum cytokines. Unsurprisingly, LA5 improved these parameters and acidified fecal pH leads to the attenuation of fecal dysbiosis. The fecal microbiome analysis in obese mice with or without LA5 indicated; i) decreased Bacteroideles, ii) reduced total fecal Gram-negative bacterial burdens (the sources of gut LPS), iii) enhanced Firmicutes (Gram-positive bacteria with potential benefits) and iv) increased Verrucomycobia, especially Akkermansia muciniphila, a bacterium with the anti-obesity property. With LA5 administration, A. muciniphila in the colon were more than 2,000 folds higher than the regular diet mice as determined by 16S rRNA. Besides, LA5 produced anti-inflammatory molecules with a similar molecular weight to LPS that reduced cytokine production in LPS-activated HepG2 cells. ConclusionsLA5 attenuated obesity through i) gut dysbiosis attenuation, partly through the promotion of A. muciniphila (probiotics with the difficulty in preparation processes), ii) reduced endotoxemia, and iii) possibly decreased liver injury by producing the anti-inflammatory molecules. Funding SourcesThis research was supported by Thailand Research Fund (RDG6150124), Thailand Government Fund (RSA6080023), the Program Management Unit for Human Resources & Institutional Development Research and Innovation-CU [Global Partnership B16F630071 and Flagship B05F630073], and Matching fund (RA-MF-12/62). TO was funded by Second Century Fund (C2F), Chulalongkorn University.