Phase feeding with different energy and protein levels in comparison with NRC and Ross feeding system on growth performance, carcass characteristics and blood metabolites of broilers

In this experiment, 160 one day old male broilers were used to compare the effect of weekly changing of metabolizable energy (ME) and protein (CP) levels with NRC and Ross feeding system on growth performance, carcass characteristics and blood metabolites of broilers. Experiment was done in a completely randomized design with 4 treatment and 4 replicates (10 birds each). There were four experimental treatments including: T1: diets formulated based on NRC recommendation, T2: diets formulated based on Ross recommendation T3: phase feeding 1 and T4: phase feeding 2. The results showed that lowering ME and CP level did not have any adverse effect on broiler performance till 14 days of age. In grower, finisher and whole period, significant effect of treatments was seen on performance traits (P