Phenotypic correlations between egg weight and some egg quality traits in three varieties of Japanese quail (Coturnix coturnix japonica)
This study was conducted to determine the relationship between egg weight and some egg quality traits in three varieties of Japanese quail. A total of 240 eggs (80 eggs/ plumage variety) obtained from 60 eight weeks old Japanese quails of three different plumage colour varieties: Pharaoh Quail (Black), A & M white (White) and Manchurian Gold (Brown) at 8-14 weeks of age were used in this study. Eggs were examined for both internal and external egg quality traits.Data obtained were subjected to one-way analysis of variance using the general linear procedure of SAS (2012). Differences in means were ranked using the Duncan’s multiple Range test. Phenotypic correlations between egg weight and other egg quality traits for each variety were also determined. Mean egg weight was significantly higher (P<0.05) in the Brown variety (10.53g) than in the Black and White varieties. Likewise the Brown variety was significantly higher (P<0.05) in egg width, yolk weight, yolk diameter, shell weight, albumen weight and height and egg index. Egg length, yolk height, shell thickness and Haugh unit however were not significantly influenced (P>0.05) by plumage varieties. Egg weight was positively and significantly correlated with egg width, egg length all external traits measured in the three varieties and with all internal traits in the Black variety. However, egg weight was negatively correlated with albumen height (-0.023) and Haugh unit (-0.228) in the White and with Haugh unit (-0.209) in the Brown variety. The results on correlation suggest that egg weight could be used as an index of egg quality in Japanese quails. Further study is recommended to explain the genetic basis for the association between plumage gene and egg characteristics in different varieties of Japanese quail.
Keywords: Japanese quail, egg quality traits, phenotypic correlation