Abstract

The present study examined the possible role of reactive oxygen species in the pathogenesis of heart failure in broilers. Our experiment was conducted with 160 one–day-old male broilers (Ross 308) to investigate the mechanisms of cell injury in the pathogenesis of pulmonary hypertension syndrome. The chickens were divided into two groups of four replicates each, with 20 chicks per replicate. One group was raised in normal temperature (NT) while the other group was raised in cold temperature (CT) to induce the pulmonary hypertension syndrome. Mortality was inspected to determine cause of death and diagnose heart failure. Hematological, biochemical and pathological tests were used to determine the incidence of PHS: total red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), activity of alanine transaminase (ALT), aspartate transaminase (AST) and lactate dehydrogenase (LDH). Malondialdehyde (MDA) was used as an indicator of lipid oxidation, subsequent to generated oxidative stress. Samples of blood and liver tissue were taken at day 21 and 42 of age. At the end of the experiment (week 6), 2 chicks from each replicate were randomly selected and slaughtered. The heart was removed, the right ventricle was dissected away from the left ventricle and septum, and the ratio of right ventricle weight to total ventricle weight (RV/TV) was calculated. The results of our experiment indicated the significant difference between the two groups for RBC and HGB and for RBC, HGB and HCT at days 21 and 42 of age, respectively. However, there was no significant difference for activity of ALT, AST and LDH in plasma between the groups at day 21 of age. but CT birds had higher levels (p < 0.05) AST, ALT and LDH activities in plasma as compared with other birds. MDA content of plasma and liver was significantly higher (p < 0.05) in CT group at both ages. RV/TV ratio and mortality due to ascites were significantly higher in CT birds. In conclusion, heart failure and subsequent PHS can be associated with oxidative stress.

Key words: Oxidative stress, heart failure, ascites, hematological, broiler.