Comparative Selenium Retention by Chicks Fed Sodium Selenite, Selenomethionine, Fish Meal and Fish Solubles

Two experiments were conducted to assay the retention of Se from varying levels of fish meal and solubles and in the second experiment to compare also the retention with that from comparable levels of sodium selenite and selenomethionine. The basal diet contained crystalline amino acid diets and high levels of α-tocopherol acetate (200 and 300 p.p.m.). In the first experiment day-old chicks were found to contain 11 μg. Se whereas chicks fed the basal diet for 21 days without any Se supplements contained 37% less. In the second experiment the day-old chicks started with a body reserve of 13 μg. Se, of which 35% was lost when fed the basal diet for 18 days. A Se balance in the chick was maintained by a dietary level of 0.05 p.p.m. from any of the sources studied. This quantity of Se was supplied by a dietary level of 2.5% fish meal or solubles. A level of 5% fish meal or solubles in the diet supplied about 0.1 p.p.m. total Se of which 16–29% was retained in the chick body in the first experiment and 15% in the second experiment. The retention value obtained in the second experiment, by supplying 0.1 p.p.m. Se from sodium selenite, was 35% and, therefore, in comparison the same levels of Se in fish meal or solubles was about 43% as effective as the standard. Compared to selenomethionine at the same level of Se, the fishery products were 31% as effective.