the effect of divergent selection on 4-wk bw on the shape of growth curve in japanese quail

the current study was conducted to investigate the effect of short-term divergent selection on the shape growth curve in different lines of japanese quail. the quail lines utilized in this study were two divergently selected for high (hw) and low (lw) 4-wk body weight during 7 generation and also a control line (c). the richard function parameters were used to describe growth curves of different lines. the weight at hatch was approximately similar among lines (8.08 g, 7.55 g and 8.76 g for hw, lw and c line respectively). the results of current study indicated that the selected lines (hw & lw) were immediately diverged from the c line after hatch. sexes within each line had no difference in average growth rate, age and body weight at inflection point and adult body weight. however significant differences were found in the growth curve parameters among lines. the results of current study indicated that short term divergent selection for 4-wk bw in japanese quail can change the growth pattern and the carcass compartments of the selected birds. therefore to avoid undesirable side effects due to selection in japanese quails it is recommended to consider the growth pattern changes of the selected birds in the breeding programs