Effects of ACTH and Acute Heat Stress on Oxidative Stress in an Early Environmentally Enriched Broilers

Abstract

Objective: In this study, the effects of early (≤21. d) environmental enrichment and acute heat stress on oxidative stress were investigated and the ability of broilers to cope with later heat stress and adrenocorticotropic hormone (ACTH) treatments were determined. Material and Methods: Six hundred day-old chicks were randomly assigned to 3 experimental groups as a control (C), environmental enrichment (EE) and environmental enrichment plus heat stress (EE+HS). At 21 d of age, broilers in EE+HS group were exposed to acute heat stress at 38±1 ˚C for 3 h. On the day 42nd, C and EE groups were divided into 2 subgroups as well Control, Control+ACTH, EE, EE+ACTH. While 50 IU ACTH/kg body weight was injected to Control+ACTH and EE+ACTH groups intramuscularly, broilers in C, EE and EE+HS groups were exposed to heat stress and oxidative stress responses of birds were evaluated. Results: Environmental enrichment did not affect blood corticosterone (CORT), malondialdehyde (MDA) and liver superoxide dismutase (SOD) levels of broilers at 21 d of age. ACTH treatment caused a significant decrease in CORT and MDA concentrations in EE broilers compared to the control group. Exposing birds to heat stress (42nd day) significantly increased CORT, MDA and decreased liver SOD levels in control as compared to EE and EE+HS groups. No significant differences were found in the SOD serum levels between groups. ACTH treatment caused more stress reactions than heat stress. Conclusion: The results obtained from this study show that exposure of broilers to acute heat stress or treatment of experimental adrenocorticotropic hormone causes preferable reactions in oxidative metabolism. It was concluded that rearing in an enrichment environment beginning from early ages can be recommended as a useful method for adaptation to stress.