PRINCIPAL COMPONENT ANALYSIS OF EGG QUALITY TRAITS OF JAPANESE QUAIL REARED IN BORNO STATE, NORTHEAST NIGERIA

Abstract

Animal breeding research usually involved large number of correlated traits which makes data analysis presumably difficult to handle and interpret. Such limitations can be handled using Principal Component Analysis (PCA). The study was conducted to estimate the variation in egg quality characteristics of Japanese quail reared in Northeast Nigeria using Principal Component Analysis. 220 Japanese quail eggs were used. Data were collected on Egg Weight (EW), Egg Height(EH), Egg Width(WE), Shell Weight(SW), Shell Thickness(ST), Albumen Height(AH), Yolk Height(YH), Haugh Unit (HU) and Albumen Index(AI). The respective mean values for the traits were 9.77 g, 2.99 cm, 2.42 cm, 0.90 g, 0.25 mm, 3.95 mm, 1.00 cm, 87.84% and 6.48%. Data were subjected to Principal Component Analysis. The three Principal factors (PCs) extracted contributed 72.14% of the total variance of the original nine egg qualities examined. The three PCs had Eigen values 2.86, 2.62 and 1.01 which accounted for 31.78, 29.14 and 11.22% of the total variance, respectively. Moderate to large communalities (0.439-0.934) were observed indicating that a large number of variance has been accounted for by the factor solution. PC 1 had high positive loadings on AH(0.957), HU(0.957) and AI(0.893); PC 2 had high positive loadings on EW(0.621), EH(0.756), WE(0.762) and a moderate loading on YH(0.497) while PC 3 had high positive loadings on SW(0.754) and ST(0.878), indicating that PC1 is a descriptor of internal egg qualities; PC2 is a descriptor of egg size qualities and PC3 is a descriptor of egg shell qualities. The PCA therefore provided the description of interdependence in the original nine egg quality traits of Japanes quails.