Evaluation of the synergistic influence of selenium and vitamin E on juvenile growth, antioxidant status, and physiological responses of heat-stressed broiler chickens

Heat stress is a growing concern in broiler production and this has been exacerbated by climate change. This study involved 300-one-day-old male Ross 308 broiler chicks, which were divided over five treatments with five replicates of 12 chickens each. The chickens were assigned in a completely randomised design as follows: conventionally reared chicks (CC), chicks subjected to early-age thermal conditioning (EATC) at 38°C for 24 h on day 5 (TC), EATC-treated chicks supplemented with vitamin E at 250 mg kg-1 feed (TCV), EATC-treated chicks supplemented with selenium at 0.5 mg kg-1 feed (TCS), and a combination of TCS and TCV (TCVS). Growth performance data and blood samples were collected and analysed at the end of the third week of the experiment. The results showed that TCVS chickens had higher body weights than CC chickens. The plasma concentration of triiodothyronine (T3) was significantly (P<0.05) higher in the TCVS chickens. Higher levels of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were detected in the TCVS, TCV and TCS groups. The plasma malondialdehyde (MDA) concentration was the lowest (P˂0.05) in the TCVS chickens. The results demonstrated that EATC combined with supplemental vitamin E and selenium (TCVS) improved performance and oxidative status in broiler chickens.