EFFECT OF SHORT-TERM DIVERGENT SELECTION FOR BODY WEIGHT AT 4 WEEK OF AGE IN JAPANESE QUAIL UNDER NORTH-SINAI CONDITIONS B. EFFECT ON GROWTH TRAITS

Abstract

Base population of the evaluated Japanese quail was derived from a randomly mated flock. This flock was used for subsequent divergent body weight selection to produce the next three generations (G1, G2, and G3). The resultant investigational birds during the period from November 2016 to November 2017 were produced and raised at the experimental farm, Department of Animal and Poultry Production, Faculty of Environmental Agricultural Sciences, Arish University, Al-Arish, North Sinai, Egypt. Individual selection for body weight at 4 wk of age was applied. The upmost 2/3 ranked birds were considered ‘the high body weight line (HL)’, while the lowest 1/3 ranked ones were considered ‘the low body weight line (LL)’. At 5 wk of age, the selected birds were transferred to cages (1 male and 2 female assigned at random from the same selection category along with avoiding sib mating). The same trend of body weight selection intensity was applied at each generation but within each line. The used experimental diet was a corn-soybean growing diet in a mash form with approximately 23% crude protein and 2850 kcal ME/kg. Feed and water were offered ad libitum. Results indicated that the interaction between body-weight-selection-type and sex was significant on most evaluated growth traits. Furthermore, line effect highly significant (P≤ 0.0001) on most evaluated growth traits. Also, the RGR decreased with the advancing in age, and higher values were recorded for both sexes and lines for RGR0-2 and reduced gradually by increasing age, also the high females was higher than males at most studied periods. However, the WG, the higher values were obtained for females in both selected lines where the HL showed higher values than the LL.