Abstract

Fermented dairy products are regarded as ideal vehicles for delivering probiotics to the human gastrointestinal tract. This study aimed to investigate the physicochemical properties of milk fermented with probiotic yeast and the protective effects of fermented milk (FM) on the colitis model. Our results showed that the lactose content of FM was decreased by 31.18%, and higher alcohols and volatile acids were increased by 98.63% and 68.44%, respectively. Yeast fermentation caused protein degradation in milk and the precipitate of FM (FM-Pre) exhibited beneficial effects on RAW264.7 cells. Dextran sulfate sodium (DSS) treatment induced significant weight loss, colon shortening, and elevated disease activity index (DAI). Notably, oral administration of FM-Pre effectively alleviated these pathological symptoms. Furthermore, the beneficial effects of FM-Pre were associated with reduced levels of inflammatory markers (MPO, IL-1β, TNF-α, and IL-6) and increased protein expression of ZO-1, MUC-2, and Occludin-1. The levels of FITC-dextran and results of tissue staining indicated that FM-Pre improved intestinal barrier integrity and confirmed the healthy status of the host gut. Therefore, FM and its precipitate could relieve DSS-induced colitis, which was associated with reduced inflammatory responses and improved gut barrier integrity.