Rearing system, utility type and hens’ age as a factor modifying lysozyme's hydrolytic activity

The aim of study was to analyze the impact of the utility type, age and rearing system of hens on egg quality traits and the enzymatic activity of egg albumen lysozyme (LA). The material consisted of 120 eggs from two genotypes of hens: Hy-Line Brown and parent stock of Ross 308. Laying-type hens were reared divided into 2 systems: intensive (litter, balanced feed) and extensive (open runs, farm fodders). The second source of material was hens age (29, 33, 41, 53 and 70 wks) of the parent stock.. Stocks were differentiated in terms of the hens age (29, 33, 41, 53 and 70 wks). Eggs quality traits and LA were evaluated. The LA of was higher in eggs from laying than from broiler breeder hens. It decreased with the hens’ age and increased with albumen mass, it was also positively correlated with albumen height and Haugh's units. The rearing system considerably modified mass of egg and albumen and the dense albumen height, but does not affect the LA.