An experiment was conducted to compare 2 levels of dietary protein (19 versus 23%) and 2 methods of feed formulation (total versus digestible amino acid) on Ross male broiler performance during 3-21 days of age. Four isocalloric (3200 Kcal MEn/Kg)experimental diets, supplemented with appropriate levels of synthetic essential amino acids to match the NRC (1994) recommendations, were fed to seven groups of five chicks to each treatment. Diets 1 and 3 contained 23 and 19% CP, respectively, along with 1.1% Lys and 0.9% SAA (NRC, 1994). Diets 2 and 4 contained 23 and 19% CP, respectively. L-Lysine and DL-Met were added (as a replacement for the starch present in diets 1 and 3) till digestible Lys and SAA became 1.04 and 0.846% (Amounts determined in previous experiments). A completely randomized design, with a factorial arrangement was employed to test the effects of the 2 dietary protein levels (19 versus 23% CP) as well as 2 methods of feed formulation (total versus digestible amino acid). Dietary protein did not show a significant effect on broiler performance but, broilers fed with diet formulated to meet the digestible rather than total amino acid requirements had a higher weight gain (485 versus 459 g). Their feed conversion was shown to be lower by 0.06 units.
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