Bifidobacterium animalis subsp. lactis A6 Alleviates Obesity Associated with Promoting Mitochondrial Biogenesis and Function of Adipose Tissue in Mice

Probiotics are widely known for their health benefits. Mitochondrial dysfunction is related to obesity. The aim of this study was to illuminate whether Bifidobacterium animalis subsp. lactis A6 (BAA6) could improve obesity due to increased mitochondrial biogenesis and function of adipose tissues. Four-week-old male C57BL/6 mice were fed with a high-fat diet (HFD) for 17 weeks. For the final eight weeks, the HFD group was divided into three groups including HFD, HFD with BAA6 (HFD + BAA6 group), and HFD with Akkermansia muciniphila (AKK) (HFD + AKK group as positive control). The composition of the microbiota, serum lipopolysaccharides (LPS), and mitochondrial biosynthesis and function of epididymal adipose tissues were measured. Compared with the HFD group, body weight, relative fat weight, the relative abundance of Oscillibacter and Bilophila, and serum LPS were significantly decreased in the HFD + BAA6 and HFD + AKK groups (p < 0.05). Furthermore, the addition of BAA6 and AKK increased the expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1 alpha) (by 21.53- and 18.51-fold), estrogen-related receptor alpha (ERR alpha) (by 2.83- and 1.24-fold), and uncoupling protein-1 (UCP-1) (by 1.51- and 0.60-fold) in epididymal adipose tissues. Our results suggest that BAA6 could improve obesity associated with promoting mitochondrial biogenesis and function of adipose tissues in mice.