Trace mineral content of conventional, organic and courtyard eggs analysed by inductively coupled plasma mass spectrometry (ICP-MS)

We investigated the contents in yolk and albumen of the trace minerals Se, Zn, Mn, Co, Cu, Mo, V, Cr, Ni, Tl, As and Cd in eggs from hens from three husbandry systems by ICP-MS. Conventional hens were given a commercial feed with added minerals, organic hens were given a feed based on organic feedstuffs also with added minerals, and courtyard hens were fed on cereals, legumes, grass and swill. Dietary Se, Zn, Mn, Co and Cu concentrations were lower in courtyard compared to conventional and organic diets; Cr concentration was highest in courtyard compared to organic diet. Trace element contents in yolks were higher than those in albumen. The highest content of Se in yolks was in organic, followed by conventional eggs. Zn contents were highest in courtyard yolk, followed by conventional, which in turn was higher than organic. Mn yolk contents were lowest in courtyard eggs; Cr contents were highest in courtyard eggs. The differences in albumen were in Zn and Cr values, which were highest in courtyard eggs. Τhe results provide baseline measurements of trace mineral contents of eggs and suggest measurable differences amongst eggs from hens in different husbandry systems; the physiological significance of these differences are discussed.