Abstract
To examine the effects of lipoic acid on metabolic response to a ${\beta}$-agonist, isoproterenol, in broilers, chicks were fed dietary lipoic acid at levels of 0 (control) or 50 mg/kg for 24 d. At 27 d of age, chickens were randomly selected. Isoproterenol dissolved in 0.9% saline was injected into the wing vein at a dosage of 2 mg per kg BW; then, blood samples were taken at 0, 10, 20, 30, 60, 90, 120, and 180 min. Amounts of plasma glucose, NEFA, triglyceride and total cholesterol were determined. Dietary lipoic acid reduced only plasma total cholesterol by 25%. Following isoproterenol injection, plasma glucose in both groups increased for 20 min; then, it returned to its basal concentration. In contrast, the maximal reductions in plasma NEFA and triglyceride in both groups (20 to 30 min) were confirmed by isoproterenol injection. In addition, while glucose returned to the basal level, plasma NEFA in the lipoic acid-treated chickens increased above the basal or control value during the 60 to 180 min post-injection. The present study suggests that the dietary administration of lipoic acid elicits fatty acid mobilization in ${\beta}$-adrenergic response to isoproterenol when the basal level of plasma glucose is maintained.