The Comparative Value of a Carotene Concentrate, Alfalfa Meal, and a Fish Liver Oil in Maintaining the Vitamin A Content of the Blood and Liver of Fattening Lambs1

Abstract

IT HAS been widely reported in the literature that carotene from different sources varies in its biological value (Ward, 1940; Fraps and Meinke, Rubin and Bird, 1941; Smith and Otis, 1941; Jones et al. 1944). Since much of this work has been done with cattle, poultry, and small laboratory animals it has little direct application to sheep nutrition. If the efficiency of utilization of carotene and other vitamin A active substances by sheep is related to the source of these materials, it should become apparent in a comparison between such widely different sources as alfalfa meal, a natural source of carotene, a carotene concentrate prepared from carrots, and fish liver oil which supplies vitamin A per se. During the course of several experiments, designed to study factors which might influence the concentration of vitamins A and C in the blood plasma of lambs, it was possible to collect data on the storage of vitamin A in the livers of lambs which had received carotene from different sources and vitamin A from fish liver oil.