<i>Bifidobacterium bifidum</i> Alleviate Intestinal Barrier Damage by Regulating the Intestinal Flora and Colonic Mucin O-Glycan Structural Patterns

<i>Bifidobacterium bifidum</i> can alleviate intestinal barrier damage, but its reliance on mucin O-glycan modifications remains unclear. A dextran sodium sulfate-induced colitis mouse model was established to evaluate the therapeutic potential of <i>B. bifidum</i> Z29-2, C5, and their mixture. The results demonstrated that <i>B. bifidum</i> alleviated intestinal injury by preventing colon shortening and goblet cell depletion, as well as reducing levels of inflammatory cytokines. Furthermore, <i>B. bifidum</i> maintained the structural integrity of gut microbiota by enriching beneficial bacteria like <i>Faecalibaculum</i> and <i>Olsenella</i>, while suppressing the abundance of opportunistic pathogens, including <i>Mucispirillum</i> and <i>Erysipelatoclostridium</i>. Additionally, strains Z29-2 and C5 promoted goblet cell differentiation and MUC2 secretion by inhibiting of the Notch signaling pathway. Crucially, these strains enhanced mucin fucosylation by upregulating Fut1 and Fut2, while maintaining glycan homeostasis by reducing O-glycan sulfation and chain truncation. This study provides deeper protective mechanism of <i>B. bifidum</i> in colitis and supports its potential application as a functional supplements.