A comparative study on egg cholesterol contents and eggshell protoporphyrin and biliverdin pigments of different poultry species

Abstract

This study was conducted to compare cholesterol levels and shell pigments (protoporphyrin and biliverdin) of chicken (conventional, organic), quail, pheasant and goose eggs. Chicken (organic system - Lohmann Brown and cage system - HyLine Brown), quail (Coturnix coturnix japonica), goose (local) and pheasant (Phasianus colchicus) eggs homogeneously selected with a subjective scoring were used as the material of the study. For each poultry species, 20 eggs were used to determine egg yolk cholesterol and eggshell protoporphyrin and biliverdin levels. Egg yolk cholesterol levels varied between 14.96–16.96 mg/g and cholesterol levels of the cage system were found lower. The greatest eggshell protoporphyrin level (81.92 µM/g) was obtained from quail eggs and the lowest (10.73 µM/g) from chicken eggs of the cage system. While biliverdin was not encountered in chicken and goose eggshells, the difference in biliverdin levels of quail (2.83 µM/g) and pheasant (1.02 µM/g) eggs were found to be significant. Further detailed research is recommended to put forth the effects of different housing systems on egg cholesterol levels and shell pigment concentrations and to identify the factors (physiological, environmental and feeding) playing a role in these effects.