The impact of breeder age on egg quality and lysozyme activity

The aim of this study was to analyze the biological components of eggs as well as lysozyme activity in relation to the age of hens. The research material consisted of eggs from parent stock of Ross 308 meat chickens. The eggs were evaluated at peak laying, i.e. eggs from 30-week-old hens, and after peak laying, i.e. from hens aged 60 weeks. Ninety eggs were evaluated in each period (180 eggs in total). Egg quality traits were divided into destructive and nondestructive traits. In addition, lysozyme activity in the albumen of the eggs was assessed. The quantitative characteristics of the eggs were found to increase with the age of the hens, with a smaller proportion of albumen and a larger of yolk. Egg weight, egg shape index, albumen and yolk weight, and air cell depth were increased with the hen?s age. The eggshell qualitative traits were changed with the hen?s age. Analyses showed that the shell weight and color of shells increased with the decrease of the density and strength of this element. In eggs from older hens marbled shells and pimples were found significantly more frequently. The lysozyme activity in the egg albumen also changed with the age of the hens. The activity of this enzyme was higher in the eggs of older hens.