Growth Rate and Lysine Requirement of the Chick

Abstract

The influence of growth rate on the requirement of the young chick for lysine has been investigated. Variations in the growth rate were achieved by selecting fast- and slow-growing individuals from one population, by adding a nonnutritive growth-depressant to the diet, by use of a fast- and a slow-growing group from two different breeds, and finally by intentionally infecting chicks with the virus of a respiratory disease (bronchitis). In all cases, the difference in growth rate did not appear to influence the lysine requirement, when growth, gain, or the instantaneous rate of growth per day were used as criteria of lysine sufficiency.