Relationships between eggshell quality parameters and albumen lysozyme activity of eggs in local amateur chickens

The aims of the study were (1) to compare eggshell quality parameters and enzymatic activity of lysozyme in the albumen of eggs obtained from local amateur chickens; (2) to evaluate correlations between eggshell quality parameters and lysozyme activity and content. The study was carried out on eggs collected from two age groups of three local amateur chicken populations: Polish Liliputy Bantams (PLB), native Polish Crested Chickens (PCr, CP-22 strain) and Gold Laced Polish Chickens (GLP). A total of 135 PLB, 75 PCr and 75 GLP chickens were kept on litter in an experimental station. Using appropriate research equipment, the physical quality parameters of the eggshell and the content and activity of lysozyme were determined. Differences were observed among these populations in some physical eggshell parameters and overall elastic deformation of eggs. On the other hand, shell strength was similar among the three populations. In addition, differences were found in lysozyme content and activity in the albumen, with higher values recorded for white eggs than for cream-colored eggs. Positive monotonic relationships were estimated between eggshell strength and shell weight, proportion of shell in the egg, and shell thickness. The variability of eggshell color parameters and age-related values of Spearman’s correlation coefficients between these parameters and shell strength indicate that non-invasive measurement of shell color can be used to predict egg resistance to damage only for the GLP population.