Combined Administration of Bifidobacterium adolescentis XA-1069 and Lactobacillus plantarum XA-6827 Attenuates Obesity in High-Fat Diet-Induced Obese Mice

Obesity, a major global health issue, is increasingly associated with gut microbiota dysbiosis and chronic inflammation. Probiotics and their derivatives have emerged as promising modulators of metabolic health. This study aimed to evaluate the anti-obesity effects of Bifidobacterium adolescentis XA-1069 and Lactobacillus plantarum XA-6827, isolated from healthy human fecal samples, administered in either live or heat-inactivated form in high-fat diet-induced obese mice. The live combination (BA+LP) significantly reduced body weight gain, adiposity, and serum lipid levels, outperforming single strains. The heat-inactivated formulation (h-kBA+LP) yielded moderate phenotypic benefits but more prominently altered gut microbiota composition, notably increasing Akkermansia. Both formulations downregulated pro-inflammatory and lipogenic gene expression. Metabolomic analysis revealed reduced deoxycholic acid and increased beneficial lipid-related metabolites, contributing to improved metabolic profiles. These findings support the complementary roles of v iable and non-viable probiotics in obesity management and highlight the potential of postbiotics as functional metabolic modulators.