Supplementation of a low protein diet in an attempt to optimize egg mass output

Abstract

Pullets were brought into production on a low-protein corn, soybean meal diet to which various nutrients including essential amino acids, choline, corn oil and feathermeal were supplemented. Production commenced between 18 and 20 wk of age and up to at least 60% production, hens fed the low protein diets (10% CP) produced at least as many eggs and as great an egg mass as these given a 17% protein corn, soybean meal control diet. Pullets fed the corn, soybean meal test diets, peaked at around 80% as compared to slightly over 90% for the control. Egg production immediately fell for birds fed the test diets to around 70% for most of the test treatments. Body weight remained constant or fell after peak production for birds fed the test diets as compared to a normal increase for birds on the control diet. Egg size increased for the test diets at a rate which was comparable to that of the control birds. In a second experiment, with older hens, supplementation of the 10% protein test diet with methionine, lysine, arginine and tryptophan, resulted in intakes of these amino acids which met NRC minimum requirement levels. However, egg mass output was reduced approximately 11% compared to the 17% protein control diet. While intakes of several essential amino acids fell below requirement levels, the degree that valine was calculated to be deficient in both experiments corresponded closely with the reduction in egg mass output of hens fed the test as compared to the control diet. Key words: Lysine, methionine, egg weight, body weight, hens.