Weanling gut microbiota composition of a mouse model selectively bred for high voluntary wheel-running behavior.

We compared the fecal microbial community composition and diversity of four replicate lines of mice selectively bred for high wheel-running activity over 81 generations (HR lines) and four non-selected control (C) lines. We performed 16S rRNA gene sequencing on fecal samples taken 24 hours after weaning, identifying a total of 2,074 bacterial Operational Taxonomic Units. HR and C mice did not significantly differ for measures of alpha diversity, but HR had a higher relative abundance of the family Clostridiaceae. These results differ from a study of rats, where a line bred for high forced-treadmill endurance and that also ran more on wheels had lower relative abundance of Clostridiaceae, as compared with a line bred for low endurance that ran less on wheels. Within the HR and C groups, replicate lines had unique microbiomes based on unweighted UniFrac beta diversity, indicating random genetic drift and/or multiple adaptive responses to selection.