Male C57BL/6J mice aged 7 weeks were purchased from Jackson Laboratories and were group housed under specific-pathogen free conditions on a 12-hr light/dark cycle (lights on 7:00 am-7:00 pm). All animals were allowed to acclimate to the facility for one week prior to the start of any treatments. Antibiotics were administered via the drinking water in an adaptation of a previously published protocol that has been shown to substantially deplete the gut microbiota4. Antibiotic doses were: Bacitracin 0.5 mg/ml, Neomycin 2 mg/ml, Vancomycin 0.2 mg/ml and Pimaricin 1.2 μg/ml. Concentrations were adjusted from the cited study as our animals did not drink the higher concentrations; vancomycin was added to increase coverage of gram positive organisms. Doses based on mean daily intake were calculated to be at or above what would normally be given to treat gastrointestinal infections. These agents were specifically selected because they are well characterized as being non-absorbed from the intestine4272829. This allows for maximal debulking of gut bacteria and minimal off-target effects due to systemic absorption. The antibiotic mixture was changed every two days and animals were
