Dietary rice bran supplementation prevents Salmonella colonization differentially across varieties and by priming intestinal immunity

The global burden of enteric dysfunction and diarrhoeal disease remains a formidable problem that requires novel interventions. This study investigated the immune-modulatory capacity of bran across rice varieties with phytochemical differences. 129SvEvTac mice were fed a 10% rice bran or control diet followed by infection with Salmonella enterica. Faecal shedding titres were quantified and flow cytometry was used to investigate intestinal immunity. The largest protection against Salmonella colonization was observed with IAC600 variety. Reduced faecal shedding correlated with increased levels of boron, soluble fibre, vitamin E isomers, and fatty acids. IAC600 and Red Wells rice bran modulated small intestinal neutrophils, macrophages, interdigitating dendritic cells, CD8⁺, γδ, and regulatory T cells, as well as CD8⁺ and γδ T cells in the mesenteric lymph nodes. Rice bran is a promising functional food and merits evaluation for the prevention of Salmonella colonization and regulation of intestinal immunity in people.