Fortification of α-Lactalbumin and β-Casein in Infant Formula Alleviate Dextran Sulfate Sodium-Induced Colitis in a Young Rat Model: Assessment of Gut Barrier, Inflammatory Response, and Metabolites.

This study evaluated α-lactalbumin (α-La)- and β-casein (β-CN)-fortified infant formula (whey:casein 60:40) on intestinal inflammation and metabolism in dextran sulfate sodium (DSS)-induced colitis in young rats. Fortification with α-La and β-CN significantly improved colonic morphology, reduced serum markers of barrier dysfunction, and upregulated epithelial junction proteins, especially occludin (P < 0.05). Fortification with α-La and β-CN significantly modulated both proinflammatory and anti-inflammatory cytokine levels in colitis-induced rats. In parallel, α-La and β-CN fortification induced genus-level shifts in gut microbiota composition, characterized by an increased abundance of beneficial genera (e.g., Akkermansia) and a decrease in potentially proinflammatory taxa (e.g., Desulfovibrio). Moreover, α-La and β-CN fortification modulated the levels of several arachidonic acid and glycerophospholipid metabolites. Correlation analysis showed that prostaglandin D2 (PGD2) and 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) were positively associated with Bifidobacterium and Blautia, whereas 2-arachidonoylglycerol (2-AG) was positively correlated with Parabacteroides and Enterobacteriaceae.