The effect of L-lysine intake on egg component yield and composition in laying hens

Abstract

Over the past two decades an increasing percentage of egg consumption has been in the form of processed eggs. Per capita consumption of processed eggs increased from 31 to 54 over the past 20 years. This comprises 21-23% of the total U. S. egg supply. Liquid egg products (LEP) are the one area of the commercial egg industry that has exhibited growth as per capita shell egg consumption decreases. The commercial value of liquid yolk and albumen is primarily evaluated by percent solids. With the increasing demand for LEP's it would be beneficial if producers had a better understanding of layer flock production, management, and nutritional effects on liquid egg composition. The focus of this experiment was the examination of dietary L-lysine monohvdrochloride (lysine-HCI) and its effects on liquid egg production. Experimental procedures were designed to examine the effect of lysine-HCI on egg component yield and composition, texture profile analysis in albumen and yolk, and yolk emulsion separations. Two experiments were conducted using standard layer rations supplemented with graded levels of lysine ranging from .71 to 2.04%. Egg production was not affected in Experiment 1, although production increased in Experiment 2, up to 1.6 % lysine. In Experiment 2, lysine levels of 2.04% resulted in significant reductions in feed consumption and egg production. Supplemental lysine increased egg weight in the first experiment while it did not in the second. Egg component yield and composition were significantly affected by supplemental lysine in both experiments. Albumen crude protein and total solids increased with elevated lysine intakes in both experiments. Yolk solids did not increase in either experiment. Yolk protein did not increase in the first experiment, whereas in Experiment 2, increased lysine intake significantly increased yolk protein levels. Texture profile analysis revealed that supplemental lysine intake did not significantly effect springiness, however, albumen hardness values were increased in a linear fashion with increasing lysine supplementation. Yolk hardness increased as well, the maximum level of yolk protein, solids, and functional properties were observed at 1040 mg lysine/hen per day. The maximum effect of dietary lysine on albumen protein was at observed 1477 mg lysine/hen per day.