Phenotypic Correlations between External and Internal Egg Quality Traits of Coturnix Quails Reared under Intensive Housing System

Abstract

Aims: The present study investigated phenotypic correlations between external and internal egg quality traits in Japanese quail. Study Design: Laboratory analysis was carried out using sensitive scale and Vernier calipers. Place and Duration of Study: Teaching and Research Farm, Department of Animal Production and Health Sciences, Ekiti State University, between September 2013 and December, 2013. Methodology: The quails were housed in the cage at the ratio of 1 male: 3 females. Freshly laid eggs were collected and taken to the laboratory for external and internal analysis. Egg weight was taken with sensitive scale, while egg length and egg width were taken with Vernier calipers. Thereafter, the eggs were broken at equatorial region and the contents poured into a dish. Subsequently, egg yolk weight, length and width, albumen length and width were measured, while albumen weight was obtained by subtracting the addition of yolk weight and shell weight from egg weight. Results: Results revealed that egg weight has no significant phenotypic correlation with egg width, egg length, shell weight and shell thickness (P>0.05). With regard to internal egg quality traits, albumen weight was found statistically insignificantly correlated with all internal qualities including Haugh unit. In the case of albumen height, positive and highly significant phenotypic correlation was recorded with Haugh unit. The implication is that albumen height is a good determinant of Haugh unit. The higher the value, the higher the Haugh unit score, and the better the quality of an egg. However, the trait has negative and significant phenotypic correlation with albumen width, yolk weight and yolk width. In addition, egg weight has positive statistically significant phenotypic correlation with albumen and yolk indices (P=0.01). Conclusion: The size of an egg determines its albumen and yolk proportions. Egg weight therefore, is a good determinant of albumen weight and yolk weight in quail bird.