Milk
oligosaccharides exert a
prebiotic action that contributes to the development of the infant gut microbiota during lactation. Given that milk
oligosaccharides remain intact after passage through stomach and small intestine, they can potentially influence the composition of the gut microbiota when ingested as dietary supplements after weaning. To address the regulatory effects of specific
oligosaccharides in
colitis linked to the microbiota composition, we have supplemented
interleukin-10 null (
Il10 -/-) mice with four fucosylated and sialylated
oligosaccharides. We found that oral supplementation with
2-fucosyllactose significantly decreased the severity of
colitis as displayed by reduced inflammatory marker expression, histological and
diarrhea scores, an increased epithelial integrity and less pronounced colon shortening. Oral supplementation with
2-fucosyllactose led to a marked expansion of the commensal Ruminococcus gnavus, which was accompanied by an enhanced cecal concentration of
propionate. Decreased activation of immune cells by R. gnavus was confirmed by reconstitution of
antibiotic-treated
Il10 -/- mice and by stimulation of dendritic cells in vitro. This study demonstrates that post-weaning administration of specific
oligosaccharides can shift the composition of the gut microbiota to lessen chronic
inflammation as observed in
Il10 -/- mice. The expansion of R. gnavus sets a positive microbial environment at the cost of pro-inflammatory Gram-negative bacteria, thereby lowering intestinal
inflammation.