Egg quality traits of laying hens reared in organic and conventional systems

This study aims to compare the physico-chemical properties of eggs (weight, eggshell breaking strength, Haugh index, yolk colour, lipid, cholesterol, protein, ash and dry matter) laid either by hens reared according to the organic method or by caged hens kept in conventional system. More than 1,400 eggs have been analysed at the beginning, in the middle and at the end of the laying cycle in organic and conventional farms. The egg obtained from the organic system were lighter (64.4 vs 66.2 g) being yolk, albumen and eggshell weights statistically lower in comparison with those produced in conventional system. The yolk/albumen ratio resulted lower in the organic eggs (0.38 vs 0.39). The percentage of eggshell was not affected by the hen rearing system while the eggshell strength resulted higher in the eggs produced in the conventional system (3.265 vs3.135 kg). The organic yolks were paler than the conventional ones. Organic eggs showed significantly higher contents of protein (17.1% vs16.7%) and cholesterol (1.26% vs1.21%).