ABSTRACT

This study was conducted to estimate the genetic parameters for growth, egg quality, and haematological characteristics of crossbred Japanese quails in humid tropical environment. A total of three hundred and sixty (360) day old chicks comprising of ninety (90) crossbred for each genotype were used for the study. Each genotype was replicated three (3) times with 30 birds per replicate, the mating ratio was 1:3. Data on fertility and hatchability, body weight and linear body traits, external and internal egg quality traits and haematological parameters were measured for each genotype. The data obtained were subjected to analysis of variance and correlation analyses in a randomized complete blocked design and significant means were separated using Duncan new multiple range test. They were also subjected to regression analysis and estimation of repeatability and heritability as appropriate. Results indicate that fertility and hatchability parameters were statistically (P>0.05) similar among the four strains. PWxCB progenies had the heaviest BWT (169.40 g) in week 9. They also recorded highest values in the following linear body parameters in cm; shank length (SL) 3.55, thigh length (TL) 4.57, body length (BL) 14.14, wing length (WL) 8.96, breast length (BRT) 7.88, and keel length (KL) 4.94 at week 9. A rapid increase in the egg weight (EWT), was found from week 6 of age to week 14 (8.28-12.06) g in PWxCB progenies. Significant and non significant differences existed in external and internal egg quality as well as in haematological characteristics measured. Age at first egg was 42 days in all the genotypes except PWxPW progenies (56) day. At weeks 6 and 8, CBxPW progenies showed positive and significantly strong phenotypic correlations (P<0.01) between BWT and SL (0.518), BWT and TL (0.720). Phenotypic correlations among the external egg quality traits of PWxPW progenies at week 10 showed positive and significant correlations (P<0.05, P<0.01) between EWT and EL (0.462), and EWT and SW (0.415).Genetic correlations between body weight and breast length ranged from 0.135- 0.944 while that of egg weight and shell weight ranged from 0.194 -0.334 in CBxPW strain. The best predictor of body weight were; KL, WL, and BRL with coefficient of regression (R²) of 92.40, this was found in PWxCB at week 6. The four strains evaluated showed high repeatability for body weight across the weeks. The heritability for body weight at week 2 for the progenies were: PWxPW (0.90), PWxCB (0.99), CBxPW (0.98), and CBxCB (0.70). Estimates of heritability for mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC) were high in PWxPW (0.62, 0.67) and PWxCB (0.61, 0.40) respectively. Finally at week 14, heritability for EWT for the progenies were: PWxPW (0.65), PWxCB (0.65), CBxPW (0.99), and CBxCB (0.98). This indicates huge influence of addictive genes. Therefore, selection effectiveness will be high at these weeks. It can then be concluded that PWxCB strain performed best in most of the parameters measured and therefore should be selected for enhanced breeding program for both egg and meat production in the humid tropic of Nigeria.