Extending laying cycle is a tendency in hen breeding, but egg quality declines as laying hens age. The present study was conducted to investigate the interactive effects of vitamins A and K-3 on laying performance, egg and tibia quality, and antioxidative status of aged Roman Pink laying hens. In a 3 x 3 factorial arrangement, 1 080 87-week-old laying hens were allocated to nine groups with eight replicates in each group. Deficient, adequate and excess vitamins A (0, 7 000 and 14 000 IU/kg) and K-3 (0, 2.0 and 4.0 mg/kg) were supplemented into a basal diet with 1 320 IU/kg of vitamin A and 0.5...
