The Influence of Dietary Calorie: Protein Ratios on the Weight Gain and Feed Efficiency of Growing Chicks

THERE is a considerable body of evidence to show that the Calorie: protein (C/P) ratio in the diet exerts a profound influence upon the growth rate, feed consumption, feed efficiency, body composition, egg production, and feathering of poultry (Berg and Bearse, 1958; Berg, 1959; Donaldson et al., 1955, 1956, 1958; Leong et al., 1955, 1959; Lockhart and Thayer, 1955; Matterson et al., 1955; McDaniel et al., 1957, 1959; Mraz et al., 1958; Scott et al., 1959; Sunde, 1956; Vondell and Ringrose, 1958). Working with rats Sibbald et al. (1957a,b,c) demonstrated that as the ratio of digestible energy to digestible nitrogen in the diet changed, the percentage of digestible nitrogen retained in the body varied in a curvilinear manner. As the amount of nitrogen retained would probably influence the change in weight of an animal, it was decided to determine whether the weight gain of chicks varied in a curvilinear manner …