Rectal temperatures are increased in BF mice compared with SPF mice and BF mice with antibiotics-induced gut flora depletion. Rectal temperatures of C57BL/6 mice upon arrival and after 1 week of housing in a BF or SPF environment. BF-housed mice that were housed for a week were also subsequently treated with broad spectrum antibiotics for a week. For the statistical analyses, only significant comparisons of interest are shown. Statistical analysis was performed with a 1-way analysis of variance (ANOVA) with Dunn multiple comparison’s test. Each dot represents 1 mouse; error bars represent standard deviation (SD). Figure shows combinatorial data from 3 experiments. *P < .05, **P < .01, ****P < .0001. NS, nonsignificant.