Taheri HR - Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
Mansouri A - Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran
Ghaderi O - Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran

Two trials were conducted to study the effect of multi-steps phase-feeding (PF) program on growth performance of broiler chickens from 1 to 24 and 1 to 39 d of age. The control group was the nutrient recommendation of Aviagen (2019) with a three-step PF program (1-10, 11-24 and 25-39 d of age). In the first trial, the control group was compared with an eight-step PF program (PF8), and in the second trial, it was compared with a thirteen-step PF program (PF13). A gradual increase of metabolizable energy and a decrease of crude protein and amino acids were applied in PF8 and PF13 over time of life. Treatments were replicated in 5 pens of 15 males per each. Feed conversion ratio, lysine intake efficiency and feed cost efficiency were improved (P ≤ 0.05) by the PF8 and PF13. In trial 1 (during 1 to 24 and 1 to 39 d of age) and trial 2 (during 1 to 39 d of age), energy intake efficiency was increased (P ≤ 0.05) by the multi-step PF program. In trial 1 (during 1 to 24 and 1 to 39 d of age) and trial 2 (during 1 to 24 d of age), average daily gain was not improved (P > 0.05) by the multi-step PF program compared to the control group; however, the PF13 increased (P ≤ 0.05) average daily gain during 1 to 39 d of age. In conclusion, the current study shows the eight-step or thirteen-step phase feeding program improves feed conversion ratio compared to the current commercial three-step feeding program. Meanwhile, the thirteen-step phase feeding program increases weight gain from 1 to 39 d of age.

Broiler, Phase-feeding, Feed efficiency