Technological quality of eggs in relation to the age of laying hens and Japanese quails

This investigation was carried out to evaluate certain egg quality characteristics of ISA Brown laying hens and Japanese quails (Coturnix coturnix japonica) in relation to their age. One hundred forty-four brown-egg ISA Brown laying hens and one hundred female quails were used in the study. A total of 1,678 eggs of laying hens and 2,060 eggs of Japanese quails were used during the experiment. The eggs for technological values were collected during two consecutive days in a 4-week period when the laying hens were from 20 to 60 weeks of age and the quails were from nine to 49 weeks of age. The results show that egg weight was affected by the age of the hens and quails (overall means 61.13 g and 12.52 g, respectively). Despite frequens fluctuations, as the age of the laying hens and quails increased, the yolk index and yolk proportion increased as well, while the albumen index, eggshell strength and shell thickness decreased. The increasing age of the hens also led to a decrease in egg shape index and eggshell proportion, but these parameters increased in the quails. A significantly higher proportion of albumen was found in the hens than in the quails, but of worse quality than in the quails as expressed by Haugh units score. The egg from ISA Brown hens had a darker yolk color than those from Japanese quails (5.90 vs. 4.87 in the La Roche scale).