Background and Aim: Production of reactive oxygen species (ROS) increases during oxidative stress conditions, which stimulates diabetes, inflammatory reactions, rheumatism and anemia. Some antioxidant properties of turmeric rhizome powder (TRP) were revealed by previous researchers. The present study was conducted to evaluate the influence of TRP on decreasing effects of oxidative stress resulted from heat stress in broiler chickens.

  Materials and Methods: In this experimental study, two-hundred-sixty-four 1-day-old broilers were divided into 3 dietary treatments. The dietary treatments involved 0(control), 0.4 and 0.8% turmeric rhizome powder (cases). In order to create oxidative stress, the ambient temperature was daily raised from 21 to 33^oc for 5 hours (11a.m-4p.m) throughout the 28th-42nd days. Blood lipids, Glutathione peroxidase (GPx) ,superoxide dismutase (SOD), and Tiobarbituric acid reaction score (TBARS) were determined at the end of the experiment.

  Results: The results revealed that total cholesterol and triglyceride were not affected. The 0.4 TRP diet decreased blood LDL (46.7±3.01) compared to basal group (52.0±2.17). HDL increased in broilers fed 0.8% TRP (74.0 ± 3.87) compared to chickens with basal diet (63.7± 2.98). Enzyme activity of GPx improved in broilers fed TRP diets (225.9± 11.52) as compared to chickens with basal diet(183.1± 8.52) however, the TRP diet did not affect enzyme activity of SOD (P > 0.05). The TBARS index decreased in broilers fed TRP
(0.76 ± 0.0052 in basal vs.0.49 ± 0.0032 in 0.8% TRP).

  Conclusion: The major bioactive component of TRP is Curcumin that can improve the antioxidant properties under oxidative stress and high ambient temperature.