The early interest in selenium (Se) focused on its toxicity, but since 1957 it has been recognized as an essential dietary element. The diet is the major Se source and approximately 80% of dietary Se is absorbed, depending on the type of food consumed. In several regions of the world, the content of Se in diets has been estimated as insufficient. The dietary requirement for Se for most species ...

Current knowledge in nutrition is based largely on the use of appropriate animal models together with defined diets. Numerous examples are cited where animal models have been used to solve nutrient x nutrient interactions, to evaluate bioavailability of nutrients and nutrient precursors, and to test for nutrient tolerances and toxicities. Advantages, disadvantages, and idiosyncrasies of various...