查看文章

In regions with selenium (Se) deficient soils, producers should supplement this mineral to the diet of forage-grazing cattle. Commercial supplements are typically formulated using inorganic forms of Se, but the organic forms are those naturally available in forages. We previously reported that circulating concentrations of progesterone are affected by the form of Se supplemented to cows. In this report, we aimed to determine (1) how the form of Se affects the expression of mRNA encoding selenoproteins in the corpus luteum, and (2) whether form of Se-induced increases in progesterone are the result of direct increases in the expression of steroidogenic transcripts. Cows were supplemented with the industry standard, an inorganic form of Se, or a 1:1 mix of organic and inorganic forms (MIX), with corpora lutea recovered on Day 7 of the estrous cycle. Transcripts encoding selenoproteins, as well as those regulating the uptake of cholesterol were affected by form of Se, but not those directly regulating steroidogenesis. We demonstrated that the expression of multiple selenoprotein mRNAs are affected by the form of Se, some of which are associated with intracellular antioxidant activity, and that the previously reported form of Se-induced increase in progesterone appears to be due to increased cholesterol availability by the corpus luteum, not by an increase in the expression of key steroidogenic enzymes.

Selenium (Se)-deficient soils necessitate supplementation of this mineral to the diet of forage-grazing cattle. Functionally, Se is incorporated into selenoproteins, some of which function as …