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 CO 2 levels during the last stage of embryonic development, and second, the prophylactic effect of β 1 -adrenoceptor blocker on right ventricular hypertrophy in broiler chickens. High CO 2 embryos showed significantly higher haematocrit values, higher partial pressure of CO 2 levels and lower partial pressure of O 2 levels than those of normal CO 2 embryos. Exposure of chick embryos to high CO 2 levels reduced the binding capacity of myocardial β -adrenergic receptors compared with those embryos incubated at the normal CO 2 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.