Oral administration of L. plantarum strains

L. plantarum AR113 and its seven bshmutant strains were obtained from Shanghai Engineering Research Center of Food Microbiology, University of Shanghai for Science and Technology (Shanghai, China).³² (link) All strains were anaerobically cultured in deMan, Rogosa, and Sharpe (MRS) medium at 37°C for 16h before centrifugation (3,000 × g for 3minat 4°C). The cell pellets were washed twice with phosphate buffer solution (pH 7.4) and then resuspended at a density of approximately 5 × 10⁹CFU/mL, which was determined by colony counting on MRS plates, for the following experiments. Each mouse was orally administered with 1 x10⁹ CFU of the strains in 0.2mL (5 × 10⁹CFU/mL) by oral gavage daily from day 5 to day 12 of the experiment.