Metagenomics and Untargeted Metabolomics Analysis Revealed the Probiotic and Postbiotic Derived from Lactiplantibacillus plantarum DPUL F232 Alleviate Whey Protein-Induced Food Allergy by Reshaping Gut Microbiota and Regulating Key Metabolites

Postbiotics have emerged as a promising alternative to probiotics. However, it remains unclear whether postbiotics can exert regulatory effects on intestinal flora and metabolism as probiotics. Thus, we investigated the effects of probiotic and postbiotic in rats with whey protein-induced food allergy, which demonstrated that postbiotic intervention effectively alleviated allergy symptoms, reduced serum immunoglobulin E (IgE) and mast cell protease-1 (mMCP-1) levels, and regulated the type helper 1 cell/2 cell (Th1/Th2) balance in both serum and spleen. Metagenomic analysis revealed that postbiotics induced more significant changes in intestinal flora. Untargeted metabolomics analysis showed that both probiotics and postbiotics significantly up-regulated various differential metabolites, which were negatively correlated with immune indices, including malvidin-3-glucoside, 3,4-dihydroxymandelic acid, nicotinamide, triterpenoids, pirbuterol, and 4-hydroxybenzoic acid. This study confirms that postbiotics can alleviate food allergies and regulate intestinal flora and metabolites, which provides a valuable reference for the use of postbiotics in mitigating allergic diseases through gut microbiota and metabolite modulation.