Efficacy of oral metformin (Metf) amidst antibiotics. Male C57 BL/6 mice (6 wk old; n = 5 per condition) were maintained on a Western-style low-fiber high-fat diet (HFD) for 8 wk. HFD-fed mice were administered drinking water containing metformin or vehicle control (Con) from wk 1 of study, with or without antibiotics (ABX) in drinking water. A and B: body weightMRI and analyzing body composition. C: epididymal fat pad pass measured post-euthanasia. D: histologic scoring of section of liver. E: mice were fasted for 5 h every 4 wk, and glucose was measured. F and G: glucose measured 0, 30, 60, and 90 min after intraperitoneal injection of glucose at wk 3 and wk 8. H: mRNA extracted from adipose and expression level of macrophage chemotactic protein-1 (MCP)-1. I and J: CXCL1 and TNFα was measured by RT-PCR. K: fecal lipocalin-2 measured by ELISA at 8 wk timepoint. Data are shown as means ± SE. *Statistical significance (P < 0.05) by Student’s t test for HFD/metformin vs. HFD control.