Effect of selenium deficiency and high selenium on biomarkers of selenium status in turkeys

This project generates turkeys with selenium (Se) status that ranges from Se-deficient to high-Se by feeding turkey poults a very low Se basal diet supplemented with graded levels of Se, and then analyzes tissues for selenoenzyme activity, for transcript (mRNA) expression for selenotranscripts and for general transcript expression, and for selenometabolites. These studies show that the dietary selenium requirement of the young turkey poult should be raised to 0.4 ug Se/g as inorganic selenium, and that the turkey is resistant to high dietary Se. These studies further indicate that the FDA limit of dietary selenium supplementation could be safely raised to 0.5 ug Se/g as inorganic selenium, at least for young turkey poults.There are, however, no good biomarkers for excess Se and toxic Se status. Because turkeys appear to be more resistant to Se toxicity, we are focusing on assessing transcripts and selenometabolites in turkeys to identify molecular biomarkers for high Se status. Identified biomarkers have potential as biomarkers to help to determine safe upper limits for dietary Se for turkeys, for other production animals, and for humans.