GROWTH RESPONSES TO SELECTION FOR HIGH BODY WEIGHT IN MEAT LINE OF JAPANESE QUAIL

The main objectives of the present study were to estimate the direct response to individual selection for high body weight at six weeks of age (BW6) with estimated the realized heritability of BW6 from two successive selected generations of this line. Besides that, estimate the correlated responses for other growth traits in meat line of Japanese quail. The results were obtained from this work; the means of body weight at different ages for selected line were higher than for control line with highly significant differences in both selected generations. with respect to generation, the results were shown the heaviest body weight at all different ages in the second generation and the lightest in the base with highly significant differences. The results revealed improving of daily weight gain during different periods for selected line in both selected generations compared control line with significant differences. Among generations, the daily weight gains during all different periods of second selected generation were the highest than the rest of generations with highly significant differences. Direct selection response of BW6 was in the first generation (16.76 g). However, selection response decreases in the second generation (5.97 g). Finally of two selected generations, the body weight at 6 weeks of age increased by 22.73 g. for selected line comparing with control line. Also, the selection for BW6 had positive correlated responses on body weight at hatch, 2 and 4 weeks of ages. The daily weight gains have improved after two generations of BW6 selection by 0.41, 0.67, 0.50 and 0.53 g/d during 0 (hatch) – 2, 2 – 4, 4 6 and 0 – 6 weeks of ages, respectively. It can conclude that the results of selection for high body weight at 6 weeks of age was caused improvement body weight at the same age and also improvements both of body weight at different ages and daily weight gain during different periods of quail growth stage. Moreover, these improvements were higher in the first generation of selection than the second.