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Abstract
The present study was carried out at the Department of Animal Husbandry and Wealth Development, Faculty of Veterinary Medicine, Alexandria University, throughout the period from January 2008 till March2009.
This study aimed to investigate the effect of divergent selection for four weeks body weight of Japanese quails reared under cage versus floor systems and different lighting systems on laying performance parameters and other related traits (Egg production, egg weight, age at sexual maturity, fertility and hatchability), as well as estimation of genetic parameters for studied trait.
The experiment included three successive generations (the base, first and the
second) divergently selected for body weight.
The main results obtained were.
I. First experiment (Cage versus floor rearing)
1.1. Selection for four weeks body weight resulted in increasing body weight from 125.34 g in base generation to 135.43 g during first generation to 136A6 g in second generation for high cage line, in addition for high floor line four weeks body weight increased from 125.34 g in base generation to 134.16 g during first generation to 135.44 g during second generation.
1.2. Fertility percentages during base, first and second generation did not showed significant differences between selected high, low and control lines either cage or floor. Higher non significant differences between cage lines (high, low and control) for hatchability percentages over floor lines in second generation (high, low and control) (88.53, 86.25 and 82.48%) versus (64.35, 65.12 and 68.47); respectively.
1.3. Non significant differences for livability between high, low as well as control body weight lines either cage or floor through two generations of selection.
1.4. High weight lines of cage and floor rearing reached sexual maturity earlier than low and random controls lines during the base generation (50.83 and 51.72 days) vs. (56.09 and 55.55 days) and (52.67 and 53.43 days); respectively, in first generation (50.04 and 49.38 days) vs. (56.57 and 56.53 days) and (53.04 and 53.15 days); respectively, moreover in the second generation (49.77 and 49.13 days) vs. (55.29 and 55.20 days) and (52.60 and 52.04 days); respectively. It was observed that floor lines either high and low recorded earlier sexual maturity than cage lines high and low during first and second generations.
1.5. High body weight cage line recorded higher non significant differences for
45 days egg production with control line but highly significant with low cage line during first generation (59.93, 52.80 and 48.02 %); respectively, as well as in second generation (72.83, 71.20 and 63.80 %). Control floor line recorded higher non significant differences with high floor line (72.73 and 68.91 %) during the second generation, while low floor line recorded the lowest egg production percentage (57.66
%).