Further evidence for the involvement of cardiac β-adrenergic receptors in right ventricle hypertrophy and ascites in broiler chickens

Abstract

The present study was carried out to determine, first, the cardiac β-adrenergic receptor characteristics of broiler chick embryos exposed to two different CO2 levels during the last stage of embryonic development, and second, the prophylactic effect of β1-adrenoceptor blocker on right ventricular hypertrophy in broiler chickens. High CO2 embryos showed significantly higher haematocrit values, higher partial pressure of CO2 levels and lower partial pressure of O2 levels than those of normal CO2 embryos. Exposure of chick embryos to high CO2 levels reduced the binding capacity of myocardial β-adrenergic receptors compared with those embryos incubated at the normal CO2 level. Atenolol-supplemented diet numerically reduced ascites incidence in broiler chickens (7%) compared with birds fed the control diet (15%). In conclusion, these data support the important role of the β-adrenergic receptor in the cardiovascular system for cardiac output, and secondary to pulmonary hypertension syndrome.