A feather protein hydrolysate was effectively produced using the keratinolytic bacterium Bacillus pumilus strain A1. In fact, complete feather degradation was achieved in medium containing up to 50 g/l of raw feathers. Cultivation of 50 g/l of feathers for two days, at 45 C and at initial pH of 10.0, resulted in maximum production of amino acids and peptides (42.4 g/l). The feather protein hydrolysate (FPH) presents a very high in vitro digestibility (98%) compared with that of the untreated feathers (2%). Furthermore, the antioxidant activities of FPH were evaluated using in vitro antioxidant assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and reducing power. Interestingly, FPH presents an important antioxidant potential with an IC(50) value of 0.3 +/- 0.01 mg/ml. These results indicate that FPH may be useful as supplementary protein and antioxidants in animal feed formulations. (C) 2011 Published by Elsevier Ltd.