Bifidobacterial blooms in the ceca of rats fed Hi-Maize starch

This study addresses the microbiology and function of a natural ecosystem (the rat gut) using DNA-based observations and in vitro experimentation. Our work revealed that increased abundance of bifidobacteria in the rat gut, induced by feeding indigestible starch, involved a species that cannot itself degrade the starch (Bifidobacterium animalis) but cohabits with a species that can (Bifidobacterium pseudolongum). This latter species has the characteristics of a keystone species in the community because it had low abundance but high ability to perform a critical function (hydrolysis of resistant starch).