Selenium-enriched Tibetan kefir grain-fermented goji juice attenuates patulin-induced liver injury and is associated with gut microbiota modulation in mice.

Background: Patulin (PAT) is a mycotoxin commonly detected in spoiled fruits and fruit-derived products. PAT exposure can induce liver injury through oxidative stress, inflammatory responses, and mitochondrial dysfunction. Aim: This study aimed to evaluate whether selenium-enriched Tibetan kefir grain-fermented goji juice (SFGJ) could serve as a protective dietary intervention against PAT-induced liver injury. Methodology: Se-enriched Tibetan kefir grains were prepared under optimized conditions, including 2% inoculum, selenium addition at 2 h, and 36 h cultivation. The optimized grains were then used to ferment goji juice at 28 °C for 36 h. Selenium content, total phenolic content, in vitro antioxidant activity, serum biochemical markers, oxidative stress indices, inflammatory cytokines, liver histopathology, and gut microbiota were evaluated. Result: The optimized Se-enriched Tibetan kefir grains contained 1356.60 ± 23.75 μg g-1 total selenium, of which 86.81 ± 0.89% was organic selenium. SFGJ showed increased total phenolic content (271.18 ± 1.20 mg GAE per 100 mL) and DPPH radical scavenging activity (80.07 ± 1.56%). In PAT-exposed mice, SFGJ reduced liver histopathological damage and decreased serum ALT, AST, and LDH levels. SFGJ also improved antioxidant status, as indicated by increased SOD and GSH-Px, and attenuated inflammatory responses by increasing IL-10 and decreasing IL-6, IL-1β, and TNF-α. 16S rRNA gene sequencing showed that PAT reduced microbial richness, whereas SFGJ treatment restored ASV richness to a level close to that of the blank control. SFGJ was also associated with increased relative abundance of Ligilactobacillus and Akkermansia and decreased relative abundance of Desulfovibrio. Conclusion: These findings suggest that SFGJ may be a promising fermented functional food for reducing PAT-associated liver injury. Its protective effect may be related to improved redox balance, reduced inflammation, and gut microbiota modulation. Further studies are needed to identify key bioactive metabolites, verify intestinal barrier function, and evaluate dose-response relationships.