Dietary supplementation with novel selenium-enriched Pichia kudriavzevii regulates gut microbiota and host metabolism in mice

Insufficient selenium intake can lead to serious health problems. However, most research on the functional properties of selenium-enriched probiotics has focused on sub-health conditions or disease models, with limited studies involving healthy subjects. Additionally, previous research has primarily explored the direct effects of selenium itself, neglecting its influence on gut microbiota and metabolism. This study aimed to explore whether long-term intake of Pichia kudriavzevii enriched with selenium affected gut microbiota and host metabolism in mice and to identify microbiota and metabolites related to beneficial outcomes. Results demonstrated that selenium-enriched P. kudriavzevii (SeY) exhibited non-toxic properties, did not cause colon or liver damage, enhanced antioxidant capacity, and reduced inflammation in a selenium dose-dependent manner. Additionally, SeY supplementation significantly altered the gut microbiota. High-dose SeY (HSeY) elevated the abundance of beneficial bacteria such as Lactobacillus and suppressed harmful bacteria such as Eubacterium nodatum group, Prevotellaceae_NK3B31_group, and unclassified_f__Lachnospiraceae. Low-dose SeY (LSeY) increased the abundance of Faecalibaculum. The strain without enriched selenium exhibited higher levels of Akkermansia compared to selenium-enriched strains. Both strains, with or without enriched selenium, stimulated the production of short-chain fatty acids. Non-targeted metabolomics analysis revealed that HSeY treatment regulated various metabolic pathways, such as tryptophan metabolism, tyrosine metabolism, and arginine biosynthesis. LSeY treatment modulated tyrosine metabolism, secondary bile acid metabolism, bile secretion, and primary bile acid metabolism. P. kudriavzevii regulated the metabolism of purine, arginine, proline, and tryptophan. Our study highlights the promise of SeY supplementation in regulating host metabolism and the gut microbiota, offering insights into its implications for promoting health.