Phenotypic Correlations Between Egg Quality Traits Amid the Laying Phase of Broiler Breeder Hens

Abstract

Summary In order to determine phenotypic correlations between the quality traits of eggs from 41-week-old broiler breeder hens (Cobb 500), a total of 105 eggs suitable for incubation were analyzed using descriptive statistics and Pearson’s correlation coefficient. The average values of egg weight, egg length, egg width, egg shape index, shell thickness, shell weight, and shell ratio were 66.90 g, 60.00 mm, 44.81 mm, 74.70%, 0.37 mm, 6.07 g, and 9.07%, respectively. Moreover, the average values of yolk weight, albumen weight, yolk ratio, albumen ratio, Haugh units, yolk index, and yolk-to-albumen ratio were 20.04 g, 40.80 g, 29.97%, 60.95%, 82.12, 46.17%, and 0.49, respectively. A significant positive correlation (p < 0.01) was found between the egg weight and the egg length (0.75), egg width (0.80), shell (0.55), yolk (0.60), albumen weight (0.91), and albumen ratio (0.25). However, a significant negative correlation (p < 0.01) was found between the egg weight and both the yolk ratio (-0.20) and yolk-to-albumen ratio (-0.23). The egg shape index proved not to be significantly correlated with any of the internal egg quality traits considered. The shell thickness was in a significant positive correlation (p < 0.01) with the shell weight (0.83) and ratio (0.86), whereas a significant negative correlation (p < 0.05) was found between the shell thickness and yolk ratio (-0.23). The Haugh units were in a significant positive correlation (p < 0.05) with the albumen ratio (0.24) and yolk index (0.27), whereas a significant negative correlation (p<0.05) was found between the Haugh units and both the yolk ratio (-0.22) and yolk-to-albumen ratio (-0.23). The results obtained confirm significant phenotypic correlations not only between egg weight and the egg quality traits considered, but also between a number of external and internal quality traits of broiler hatching eggs.