Infant Fecal Fermentations with Galacto-Oligosaccharides and 2'-Fucosyllactose Show Differential Bifidobacterium longum Stimulation at Subspecies Level.

The objective of the current study was to evaluate the potential of 2'-FL and GOS, individually and combined, in beneficially modulating the microbial composition of infant and toddler (12-18 months) feces using the micro-Matrix bioreactor. In addition, the impacts of GOS and 2'-FL, individually and combined, on the outgrowth of fecal bifidobacteria at (sub)species level was investigated using the baby M-SHIME model. For young toddlers, significant increases in the genera , , and , and decreases in , XIVa, and were observed in all supplemented fermentations. In addition, GOS, and combinations of GOS and 2'-FL, increased and decreased , whereas 2'-FL, and combined GOS and 2'-FL, decreased . Alpha diversity increased significantly in infants with GOS and/or 2'-FL, as well as the relative abundances of the genera and with 2'-FL, and with GOS. Combinations of GOS and 2'-FL significantly stimulated , , , and . In all supplemented fermentations, Proteobacteria decreased, with the most profound decreases accomplished by the combination of GOS and 2'-FL. When zooming in on the different (sub)species of , GOS and 2'-FL were shown to be complementary in stimulating breast-fed infant-associated subspecies of in a dose-dependent manner: GOS stimulated subsp. , whereas 2'-FL supported outgrowth of subsp. .