Effect of feeding selected strains of conserved breed hens with diets containing legumes on egg quality and content and activity of lysozyme

Abstract The aim of the study was to evaluate the effect of replacing soybean meals with legume grains in diets on laying performance of hens and egg quality, with particular emphasis on egg lysozyme content. The study included 4 breeds/strains of laying hens included in the conservation programme in Poland, i.e.: Green-legged Partridge (Z-11), Yellow-legged Partridge (Ż-33), Rhode Island Red (R-11), and Leghorn (H-22). At 41–56 weeks of age, the hens of each strain were divided into two groups: I (control) – fed ad libitum with a standard diet based soybean meal, and II (experimental) – fed ad libitum with a diet that contained beans, peas and lupins instead of soybean meal. At 56 weeks of age, 32 eggs were taken at random from each group of hens and each strain, which were subjected to quality assessment. The results of the study confirm the possibility of feeding the above-mentioned hens with a diets in which soybeans were replaced with 28% of faba bean, pea, and yellow lupin grains without a significant effect on laying performance, but with a change in some egg quality characteristics. In groups of hens fed a diet without soybean, a decrease in egg and albumen weight, albumen and yolk pH values, and an increase in yolk colour towards yellow were recorded, as well as an increase in Haugh units and air cell height and shell porosity. There was a significant effect of genotype and diet and simultaneously of both factors on the content and activity of lysozyme in the thin and thick albumen. In the experimental groups, the average content and activity of lysozyme in the thin albumen decreased and in the thick albumen increased. Regardless of diet, statistically significant variation in egg internal quality and egg shell quality between hen strains was shown, as well as a correlation between the content and activity of lysozyme in eggs and shell colour.