Effect of protein and energy intake by broiler breeders during the prebreeder transition period on subsequent reproductive performance

ABSTRACT Two levels of protein and two levels of energy were fed to broiler breeders during the prebreeder period (18 to 23 weeks of age) after which a standard breeder diet was provided to all birds. The differences in intake during the prebreeder period was 140 g protein/bird between the high protein (HP) and low protein (LP) groups and 1145 kcal ME/bird between the high energy (HE) and low energy (LE) groups. Body weights did not differ during the prebreeder period or subsequent breeder period. Cumulative egg production was similar among all treatments with numerical advantages for HP and LE birds due to improved production after 55 weeks of age. Significant protein X energy interactions occurred for egg weight during Weeks 25 to 44, but no significant overall effect was observed. Egg specific gravity was not affected significantly. Fertility did not differ; however, the LP birds exhibited significantly better hatch of fertile eggs and significantly decreased late deads when compared to HP birds. The HE birds exhibited significantly less early embryonic mortality but significantly more late embryonic mortality when compared to LE birds. Hatch of fertile eggs did not differ due to prebreeder energy levels. (Key words: broiler breeders, egg production, hatchability