Lysine and methionine supplements in diets for laying pullets

Abstract

In two experiments the effects of supplementary methionine (0.10%) and lysine (0.08% in experiment 1 and 0.10% in experiment 2) on the performance of three strains of laying pullets were examined. In both experiments small but significant responses to methionine were observed, in egg weight and daily egg mass in experiment 1 and in daily weight gain in experiment 2. In both experiments large and significant increases in rate of lay and egg weight resulted from addition of lysine. It was concluded that lysine was a major limiting amino acid in the diets used. In the second experiment a high protein (18.1%) diet produced significantly higher peak production, rate of lay and egg weight than a low protein (14.3%) diet. It was concluded that a difference in lysine content of the diets was primarily responsible for the differences. Significant strain x methionine and strain x lysine interactions were observed. Lysine requirements, however, could be predicted in the second experiment by the regression equation: Total lysine required (mg/day) = 0.086 W + 8.71G + 11.17E where body weight (W), daily weight gain (G) and egg mass (E) are expressed in grams. Predicted lysine requirements based on this regression are compared with predictions based on published multiple regression equations.