This study draws attention to OA as feed additives in broiler nutrition to improve feed efficiency, weight gain, and carcass yield. Also, the present findings show that reducing dietary CP level had no detrimental effect on weight gain during the starter and finisher periods when the limiting amino acids were provided at the sufficient quantities. On the other hand, reducing dietary CP level by 1 percentage point resulted in a marked decrease in serum uric acid, which is of great importance from bioenvironmental issues viewpoint. The influence of supplemental OA on dietary protein and amino acid requirements of different poultry species, however, needs further and extensive investigations.