Comparison of Egg Composition and Conservation Ability in Two Belgian Local Breeds and One Commercial Strain

The study was conducted to evaluate the egg quality of two Belgian local chicken breeds (the Ardennaise and the Famennoise) and to compare it with a commonly bred commercial strain (Lohmann brown). Two criteria were used to describe egg quality: egg composition (measured through yolk to albumen ratio) and its stability during conservation (measured through pH). Egg weight, size, composition as well as albumen pH were measured on 140 eggs. Measurements were performed at days 0, 7, 14 and 21 after laying. The egg weight was highest in the Lohmann strain (62.86 g), followed by the Famennoise breed (55.51 g) and lowest in the Ardennaise (50.31 g). Yolk to albumen ratio was significantly higher in the Ardennaise (0.53) when compared with the Famennoise (0.49) and Lohmann breeds (0.43). Albumen pH at laying was lowest in the Lohmann when compared with the local breeds. However, no statistical differences among the three breeds could be detected for this parameter at days 14 or 21 postlaying. The high pH in local breed eggs is often reported to be caused by a lower conservation ability. The present results suggest some physiologically higher pH at laying not resulting from defaults in conservation. As a measure of egg freshness, pH must be adapted by the various poultry breeds.