Value of Selenium in Alfalfa for the Prevention of Selenium Deficiencies in Chicks and Rats

The value of the Se contained in alfalfa grown at a low level of available S, and in alfalfa grown at a high level of available S, was compared with that of Se from Na2SeO3 for the prevention of exudative diathesis in chicks and liver necrosis in rats. All of the sources of Se were supplied as additions to basal diets low in vitamin E and containing Torula yeast as the principal source of protein. The amount of alfalfa in the diets was held constant by using a low Se alfalfa in the diets containing Na2SeO3. Since the added alfalfa made up less than 2% of the total diet, levels of dietary S were nearly constant for all comparisons of Se sources. Se from the different sources, i.e., Na2SeO3, low S alfalfa and high S alfalfa, tended to be of similar value for the prevention of liver necrosis in rats and in the promotion of growth in both species. The Se in the high S alfalfa was about 25% less effective than the Se from the other sources for the prevention of exudative diathesis in chicks.