The Effect of Dietary Protein and Energy Levels During the Growing

A (3 x 3) factorial arrangement was used in a completely randomized design to study the effect of early nutrition of pullet on subsequent egg production and quality. Three levels of protein and three levels of energy during stages of pullet growth (starter 0-6 wk, grower 7-12 wk and developer 13-18 wk of age) and their effect on laying performance (22-36 wk of age) were evaluated. In all phases of growing period, control levels of protein (P1) and energy (E1) were set according to NRC (1994) and the other levels were higher, for protein in 2% steps (P2 and P3) and for energy by 100 kcal of ME/kg steps (E2 and E3). Each treatment was replicated three times with ten birds each. Treatments in the factorial arrangement were kept the same for bird groups in every phase but at 19 week of age all groups were shifted to the identical layer diet up to the end of the trial. The layer performance of the different treatment groups was evaluated. In phase one of egg production cycle (22-36 week of age), hen-day egg production was influenced (p<0.01) by protein levels fed to the birds during the growing period. P2E3 diet had the best hen-day egg production. Egg mass was significantly (p<0.01) affected by dietary protein levels fed to the birds during the growing period. The higher dietary protein levels (P2 and P3) fed to the birds during the growing period had higher egg mass than those fed the lowest protein level P1. Egg weight, egg length, egg width and feed consumption were not influenced by dietary protein levels fed to the birds during the growing period. Egg weight, mass, length, width and shape index and feed conversion were not affected by dietary energy levels fed to the birds during the growing period. Thus, feeding the higher protein levels (P2 and P3) had the highest hen-day egg production and egg mass. The best egg mass and egg production were recorded with P2E3 diet, so the feeding of the pullets with P2E3 diet during the growing period will give best hen-day egg production.