This study aimed to evaluate the effect of different levels of watercress (Nasturtium officinale) powder on growth performance, antioxidant status, and blood parameters in broiler chickens. A total of 240 day-old male broiler chicks (Cobb-500) were divided into 04 treatments with 04 replicates of 15 birds each. Dietary treatments were included a corn-soybean diet as a control group along with diets containing 0.5, 1 and 1.5 % of watercress powder. The results showed that inclusion of 0.5, 1 and 1.5 % of watercress powder significantly (P<0.05) increased feed intake at 11 and 23 days of age. The inclusion of 0.5 % watercress powder significantly decreased (P<0.05) the total cholesterol in the serum of the chickens. There was no effect of watercress supplementation on glutathione peroxidase, total superoxide dismutase activities, and malondialdehyde concentration in the liver. Supplementation of diet with 1 and 1.5 % watercress powder increased (P<0.05) total glutathione peroxidase activity in red blood cells and total antioxidant capacity of serum, however serum malondialdehyde concentration remained unaffected. The results of present study suggested that supplementation 1% of watercress powder improved antioxidant status and could be considered as a replacement for synthetic antioxidants in diet.

Keywords: Antioxidant status, blood parameters, broiler chickens, growth performance, Nasturtium officinale