Obesity is a major global health concern associated with metabolic complications such as insulin resistance, dyslipidemia, and chronic inflammation. Hence, we investigated the effects of heat-treated culture-dried Lactiplantibacillus plantarum L-14 (L14) supplementation on lipid metabolism and obesity-related metabolic dysregulation in a high-fat diet (HFD)-induced mouse model. Male C57BL/6J mice were fed an HFD with or without L14 supplementation for 10 weeks. Throughout this period, body weight, fat mass, and biochemical parameters were evaluated, while adipose tissue was analyzed for histological changes and gene expression related to lipogenesis and lipolysis. L14 supplementation significantly reduced body weight and fat mass without affecting food intake. Serum glucose levels, lipid profiles, and liver function markers were improved in the supplemented groups. Histological and micro-CT analyses showed reduced fat mass and adipocyte size in adipose tissue. At the molecular level, L14 downregulated key lipogenic genes SREBP-1, PPARγ, SCD1, FAS, ACC, and DCAT while upregulating genes AMPK, PGC-1α, PPARα, ATGL, HSL, UCP-1, and CPT-1 involved in lipolysis and fatty acid oxidation. These findings indicate that L14 suppresses lipid synthesis while enhancing lipid breakdown and energy utilization in adipose tissue. L14 effectively mitigated HFD-induced obesity and metabolic dysregulation by modulating lipid metabolism in adipose tissue. These results suggest that L14 has potential as a functional probiotic for the management of obesity and related metabolic disorders.
