COBALT-INDUCED POLYCYTHEMIA CAUSING RIGHT-VENTRICULAR HYPERTROPHY ANDASCITES IN MEAT-TYPE CHICKENS

Cobalt increases the red cell mass in both man and animals by increasi ng the production of erythropoietin. Since meat-type chickens can deve lop pulmonary hypertension from increased erythropoiesis and polycytha emia, two trials were conducted to investigate the role of cobalt on b roiler chicken erythropoiesis and pulmonary hypertension. The results showed that feeding cobaltous chloride at 500 parts/10(6) to meat-type chickens from 1-day-old for 42 days significantly increased haemoglob in content and, to a lesser extent red blood cell count, and haematocr it. No effect was observed on mean corpuscular volume. Increased haemo globin content was linearly correlated with pulmonary hypertension as measured by the right ventricle weight to total ventricle weight ratio (RV:TV). Levels of malondialdehyde in cardiac tissue were also correl ated with the RV:TV ratio, suggesting that peroxidative damage may be related to ventricular hyper-trophy. Chickens fed cobalt showed a sign ificantly higher incidence of right ventricular hypertrophy and right ventricular failure and 18.3% developed ascites.