Quality of chicken eggs in relation to their weight category

The purpose of this study was to evaluate selected quality traits of chicken eggs in relation to theirweight (weight categories). The experimental material comprised eggs from 250 laying hens (♂ NewHampshire x ♀ Barred Rock). The birds were kept in a poultry house on litter in identical hygienicconditions and fed ad libitum the same compound feed, of appropriate nutritional value, during therearing and egg production period. At 36 weeks of age 160 eggs were taken at random from the hensand divided into four weight categories: below 57.0 g (group A); 57.1 to 60.0 g (group B); 60.1 to 63.0 g(group C) and above 63.0 g (group D). The quality of the albumen, yolk and shell was evaluated andthe concentration and hydrolytic activity of lysozyme was determined in individual albumen fractions.Eggs from group D had the highest share of albumen (60.92%) and the smallest share of shell (10.56%).Furthermore, the albumen of these eggs had the greatest weight (40.19 g) and height (6.61 mm), and theyolks had the highest weight (18.13 g) and darkest colour (13.65 pts). The eggs assigned to group B hadgreater shell thickness (352.46 μm) and strength (38.2 N). Detailed analysis of lysozyme activity showedthat the albumen of the group A eggs had the highest lysozyme concentration and hydrolytic activityin both albumen fractions analysed (0.61%; 131,105 U/ml – thin albumen and 0.38%;80,705 U/ml– thick albumen). The study showed that the heaviest eggs had the most favourable traits for theconsumer. They were distinguished by good albumen quality (the greatest weight and height) and yolkquality (the greatest weight and darkest colour). Moreover, their shells were fairly thick (352.37 μm)and the least susceptible to deformation (70.90 μm). On the other hand, the albumen of the eggs in thelowest weight category had the highest concentration and hydrolytic activity of lysozyme.