Effect of different amino acids density diets on lysine, methionine and protein efficiency in Arian broiler

The advantages provided by amino acid (AA) densities to broiler performance have been well documented, but little research has been reported on comparing the effect of different densities, i.e. high, medium, standard and low amino acid levels (HAA, MAA, SAA, and LAA), on protein and energy efficiency in broiler. This study evaluated the effects of the four different amino acid densities in a completely randomized experimental design on 800 male (10 replicates per treatment) broilers. All diets were isocaloric and isonitrogenous. In broilers receiving HAA, there had been a significant increase in body weight at Day 42. Feeding broilers with HAA diets significantly increased protein and energy intake in the grower period and during the overall study period (0-42 days of age) (P<0.05). There was a significant difference in efficiency of lysine and methionine during all time periods (P<0.05) and HAA levels were significantly higher than SAA. Protein efficiency ratio (PER) and energy efficiency ratio (EER) were not affected by an increase in AA density. AA levels had a significant effect on production efficiency factor (PEF). The results of this study suggest that additional lysine and methionine at 120% and other AA at 110% of National Research Council recommendations in starter and grower diets significantly improved body weight and PEF.