Rhodotorula mucilaginosa JAASSRY Alleviated Oxidative Damage in D-Galactose-Induced Aging Mice by Modulating the Gut Microbiota

As one of the few carotenoid-producing microorganisms,Rhodotorula mucilaginosaremains underexplored for its antioxidant activity. This study investigated the effects ofR. mucilaginosaJAASSRY on D-galactose-induced aging mice. The high-dose JAASSRY (HR) significantly increased body weight by 9.89% compared to the model group (AM), while reducing organ indices of the spleen, liver, kidneys, and brain (p< 0.01). Compared with the AM group, the HR group exhibited increased serum activities of SOD (20.26%), GSH-Px (9.03%), and CAT (133.01%), with a 24.87% decrease in MDA level. In brain tissue, SOD, GSH-Px, and CAT activities increased by 79.49%, 8.45%, and 60.23%, respectively, while MDA decreased by 8.29%.R. mucilaginosaJAASSRY also dose-dependently alleviated structural damage in the hippocampus and spleen and improved motor strength and learning-memory capacity. Furthermore,R. mucilaginosaJAASSRY increased the abundance ofLactobacillusand reducedProteobacteria,Helicobacter, andOscillospira, while enhancing antioxidant capacity by modulating nucleotide, lipid, and carbohydrate metabolism.LactobacillusandPediococcuswere positively correlated with memory latency and CAT/SOD activities (p< 0.05), whereasActinormycesandDehalobacteriumshowed negative correlations. Notably, HR performed comparably or superiorly to β-carotene in improving cerebral oxidative stress and beneficial microbiota, suggesting its potential in neuroprotection and gut–brain axis regulation. In conclusion,R. mucilaginosaJAASSRY mitigates aging-related oxidative damage and behavioral deficits by modulating gut microbiota structure and function, demonstrating its promise as a β-carotene alternative in animal husbandry and functional foods.