Altering the intestinal microbiota during a critical developmental window. mouse gut metagenome

Disruption of the microbiota by low-dose antibiotic exposure can alter host metabolism and adiposity. We now show that low-dose penicillin (LDP) delivered from birth enhanced metabolic alterations, and that there were additive effects in combination with high fat diet. LDP that was limited to early life was sufficient for sustained effects on body composition. After the cessation of penicillin, the microbial communities recovered, yet metabolic phenotypes persisted, indicating that microbiota interactions in infancy may be critical determinants of long-term host effects. Early-life LDP was associated with alterations in ileal expression of genes involved in immunity. The growth promotion phenotype was transferrable to germ-free hosts by LDP-selected microbiota, not antibiotics per se. These studies characterize important variables in early-life microbe-host metabolic interaction, and identify several taxa consistently linked with metabolic alterations.