Expression data from pituitary of steers grazing endophyte-infected tall fescue and supplemented with different forms of Se

The goal of this study was to test the hypothesis that sodium selenite (ISe), SEL-PLEX (OSe), vs. a 1:1 blend (MIX) of ISe and OSe in a basal vitamin-mineral (VM) mix would differetianlly alter pituitary transcriptome profiles in growing beef steers commonly grazing an endophyte-infected tall fescue pasture. Predominately-Angus steers (BW = 183 ± 34 kg) were randomly selected from herds of fall-calving cows grazing E+ pasture and consuming VM mixes that contained 35 ppm Se as ISe, OSe, and MIX forms. Steers were weaned, depleted of Se for 98 d, and subjected to summer-long common grazing of an E+ pasture (0.51 ppm total ergovaline per ergovalinine; 10.1 ha). Steers were assigned (n = 8 per treatment) to the same Se-form treatments upon which they were raised. Selenium treatments were administered by daily top-dressing 85 g of VM mix onto 0.23 kg soyhulls, using in-pasture Calan gates. We collected pituitary samples and examine for changes in global expression pattern by microarray analysis. 20 total samples were analyzed (n = 6 for ISe, and n=7 for both OSe and MIX).