Absorption and Distribution of Selenium Following Oral Administration of Selenium-Enriched Bifidobacterium longum...

Selenium (Se) is one of the essential elements required to maintain human health. Although various kinds of Se supplements are now available on the market, their biological activities and toxicities vary based on the transportation characteristics of Se. In this study, we compared the absorption and distribution of Se in rats administered with different Se supplements: Se-enriched Bifidobacterium longum DD98 (Se-DD98), selenized yeast (Se-Y), and sodium selenite (Na₂SeO₃). Se-DD98, Se-Y, and Na₂SeO₃ were orally administered to rats. The plasma Se content at different time points after administration was determined within 72 h. Pharmacokinetic parameters were analyzed to reveal the absorption of Se. Se-DD98, Se-Y, and Na₂SeO₃ were also repeatedly administered by oral gavage for 30 days, and Se content of the heart, liver, spleen, lungs, kidneys, and muscle was determined to analyze the distribution of Se. The results showed that the organic Se supplements (Se-DD98 and Se-Y) were more easily absorbed into the blood and retained longer in the plasma than the inorganic Na₂SeO₃ was. Moreover, Se-DD98 induced better absorption of Se in plasma than Se-Y did. Furthermore, significantly higher concentrations of Se were found in the heart, liver, spleen, kidneys, and muscle of rats administered with organic Se supplements (Se-DD98 and Se-Y) than those administered the inorganic Na₂SeO₃. Rats administered Se-DD98 accumulated more Se in the spleen, lung, and kidney than those administered Se-Y, while Se-Y led to higher concentration of Se in the liver compared to Se-DD98. These results suggest that the organic form of Se was better absorbed and accumulated than the inorganic form was. Se-enriched B. longum DD98 induced greater absorption of Se in plasma and accumulation of Se in several organs than the selenized yeast did, which could suggest the potential superior nutritional function of Se-DD98.