This study was conducted to determine the effect of dietary supplement of bacterial lycopene (BL) produced by Escherichia coli on the egg quality and blood characteristics of laying quails. The antioxidant activity measurement showed that BL exhibited 100% 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity at a concentration of 4.65 mu g/ml, which was more effective than butylated hydroxytoluene (BHT) and commercial lycopene (CL). Moreover, seven dietary groups of laying quails consisting of 10 100-day-old quails (Coturnix coturnix japonica) each were fed with the basal diet supplemented with BL, CL or canthaxanthin (CA) for 4 weeks. Consequently, the triglyceride content of yolk was significantly lower in the group with BL and CL supplement. The serum malondialdehyde (MDA) level of the BL- and CA-supplemented groups at 18 mg/kg was lower than the control group. In conclusion, BL has a high antioxidant activity and is promising as a feed additive in the diet of laying quails. (C) 2015, The Society for Biotechnology, Japan. All rights reserved.