Four types of fresh shell eggs (n = 72 each) were used in this
study. The eggs were not sterilized or UV treated before. Normal
table eggs and eggs from two heritage chicken breeds (white leghorns
and brown leghorns) were obtained from the Poultry
Research Centre of the University of Alberta (Edmonton, AB,
Canada). Heritage chicken breeds are characterized by an original
genetic line; they are not selected based on egg laying or quality
performances. Eggs enriched in lutein and omega-3 fatty acids
were purchased from a local supermarket (Edmonton, AB,
Canada). Eggs were stored under normal retail storage conditions,
i.e. at 4 C in packages for 35 days and analyzed on a weekly basis.