Immune response of broilers to vitamin C and coenzyme Q10 under cold stress condition

This experiment was conducted to determine the effect of vitamin C (VC) and coenzyme Q10 (CoQ10) on immunity response of broilers in cold stress condition using 500 male chicks in a completely randomized design with 5 treatments and five replicates. Treatments were: positive control (PC، normal conditions growth without antioxidants)، negative control (NC، cold stress without antioxidants)، cold stress + VC (300 mg/kg diet)، cold stress + CoQ10 (40 mg/kg diet) and cold stress + VC + CoQ10 at above mentioned doses. To induce cold stress، from day 15 until end، temperature fixed at 15oC. Vaccine titers، humeral and cellular immune response and relative immune organs weight were studied. Results showed that cold stress decreased relative spleen weight but there was no significant difference between treatments. Relative weight of bursa was increased in cold stress condition (P<0. 01) and using antioxidant especially CoQ10 decreased it (P<0. 05). Lymphocyte percent decreased in cold stress (P<0. 05). Improved cellmediated immune response to subcutaneous injection of phytohemagglutinin and proliferation of T lymphocyte in vitro were observed (P<0. 05). In conclusion، use of antioxidants VC and CoQ10 in the cold stress condition improved immune system activity and decreased mortality