The Gut Microbiota – A Realistic Therapeutic Target in Obesity and Metabolic Dysregulation

Background: The gut microbiota is an environmental regulator of fat storage and fat composition. We and others have shown the primacy of diet in influencing the microbiota in obesity. Whether the microbiota represents a realistic therapeutic target for improving metabolic health is unclear. Aim: To explore two antimicrobial strategies for their impact on metabolic abnormalities in murine diet-induced obesity (DIO) using: (a)oral vancomycin, (b)a bacteriocin- producing probiotic (Lactobacillus salivarius UCC118Bac+) and (c) its bacteriocin-negative derivative (UCC118Bac-). Methods: Male (7-wk-old) C57BL/J6 mice (n=9-10/group) were fed a low-fat diet (lean) or a high-fat diet (DIO) for 20 weeks with/without vancomycin by gavage at 2mg/d, or with/without the Bac+ or Bac- probiotic (each at a dose of 1x109 cfu/day by gavage). Compositional analysis of the microbiota was by metagenomic pyrosequencing. Results: The metabolic abnormalities of diet-induced obesity were associated with increased relative proportions of Firmicutes (60.7+/-2.8 vs 70.2+/-2.4%; p