Selenium is an essential trace element with important benefits in human and animal health. Selenium functions in enzymes reducing oxidative stress and allowing for a better antioxidant status, but it can also improve reproduction parameters, immune responses, performance and meat quality. Selenium is naturally present in raw materials, mostly in the form of L-selenomethionine.

However, the level of selenium in plant-based feedstuffs is dependent on the selenium levels in the soil, and is often quite low and variable. Therefore, it is important to supplement the feed with additional selenium. The supplemented selenium can be either in an organic or an inorganic form. Different forms of selenium differ greatly in bioavailability.