Dietary Adrenergic Active Compounds and The Response of Broilers to Isoproterenol and Cyclic Adenosine Monophosphate in Vitro

Abstract

Broiler chickens, growing from 7–28 days of age, were fed diets containing 18% protein and 0, 1, 10 or 100 mg/kg yohimbine (alpha2-adrenergic antagonist) or metaproterenol (beta-adrenergic agonist) to determine the role of adrenergic agents in the regulation of feeding behavior and metabolism. Data from this experiment suggest that beta-adrenergic agonists have slight effects on feed intake, growth and more pronounced effects on metabolism in the broiler chicken. In vitro lipogenesis (IVL) was determined by incubating liver explants for 2 h at 37°C in the presence of cAMP or isoproterenol (ISO) and [2-14C]acetate and by measuring acetate incorporation into total hepatic lipid. Metaproterenol and yohimbine (100 mg/kg) depressed growth from 7 to 28 days. Both metaproterenol and yohimbine (100 mg/kg) decreased (P < 0.05) IVL compared to controls. These dietary additions also decreased (P < 0.05) hepatic malic enzyme activity without affecting the activities of either isocitrate dehydrogenase or aspartate aminotransferase.