The Influence of Dietary Energy Level, Energy Source, Breed and Sex on Vitamin A Requirement in the Chick

Abstract

REVIEW OF LITERATURETHE dietary requirement for vitamin A in the young chick has been estimated to be 1,200 U.S.P. units per pound of feed (National Research Council, 1954). Although this estimate is based on work prior to 1954 (Wilson et al., 1936; and Record et al., 1937), which showed that levels of 1,200 U.S.P. units and lower were sufficient for normal growth and health of chicks, considerable question has arisen as to its adequacy under current conditions.The development of the faster growing bird, the advent of the high energy ration and the production of vitamin A supplements of increased stability are among various factors which may be influential in changing the dietary requirement for vitamin A. Thus it is important that the requirements for such nutrients be reevaluated periodically. In some recent work, Scott et al. (1957), found that 400 to 600 U.S.P. units of vitamin A were …