Role of organic selenium in resisting oxidative stress during tropical summer in broiler chicken

The present study was conducted to investigate the effect of selenium supplementation on the oxidative status of hepatic tissue during heat stress in broilers. The study was conducted in two phases, one during autumn and the other during summer with a total of 300 birds. During the first phase, 60 chicks were divided into six replicates with 10 birds in each and during the second phase, 240 chicks were divided into four groups with six replicates containing 10 birds in each. The experimental rations given to different groups were control (Basal ration), HS I (Basal ration), HS II (Basal ration + 0.3 ppm Se, HS III (Basal ration + 0.6 ppm Se) and HS IV (Basal ration + 0.9 ppm Se). Hepatic tissues collected at 21 and 42d were analyzed for oxidative status. HS-induced oxidative stress was revealed by the significant elevation in lipid hydroperoxides, MDA and protein carbonyl levels which in turn triggered the activities of anti-oxidant enzymes, i.e GPx, GST, SOD and G6PD in the hepatic cytosol. The total antioxidant capacity and glutathione concentration were significantly altered due to HS. Selenium at 0.3 ppm was effective in counteracting the oxidative stress at 21d while 0.6 ppm of Se was more effective at 42d. Se supplementation at 0.6 ppm improved the activities of antioxidant enzymes and G6PD. The total antioxidant capacity and GSH concentrations were better improved with 0.6 ppm of Se compared to other treatments.