Two basal diets containing an adequate and a low supply of available P (4.7 vs 2.5 g/kg diet) and three others containing a low available P but supplemented with 250, 500 and 12,500 units of phytase (FTU) per kg diet, respectively, were prepared. Each diet was fed ad libitum to birds in six metabolism cages (five birds in each cage) in a randomised block design. It was found that birds fed a high (12,500 ETU) dosage of phytase grew faster (P < 0.001) and retained proportionally more carotenoids in the liver (P < 0.05) compared to birds fed unsupplemented diet. The results suggest that dietary phytase may improve the anti-oxidative status of birds fed low P diets through enhancing dietary carotenoid availability. (C) 2010 Elsevier Ltd. All rights reserved.