Performance of White- and Brown-Egg Pullets Fed Varying Levels of Diet Protein with Constant Sulfur Amino Acids, Lysine, and Tryptophan

Abstract

Two experiments were conducted with either white or brown egg pullets to observe their growth and development when fed low protein diets supplemented to normal calculated levels of methionine, methionine + cystine, lysine, and tryptophan. Regardless of diet energy level, pullets were smaller in weight and stature when the protein level declined. This weight differential was maintained through a full laying cycle, during which there was a clear trend of smaller weight birds producing smaller eggs. Egg production and other egg characteristics were unaffected by protein levels in the growing diet. It is possible that the reduction in crude protein level of pullet grower diets will be controlled by the economics of using crystalline threonine.