Continuous infusion of lipoic acid rapidly reduces plasma β-hydroxybutyrate with elevation of non-esterified fatty acids in broiler chickens

The present study was conducted to determine the effects of a-lipoic acid (ALA) on fatty acid mobilisation and ketone body production in female broiler chickens. In the first experiment, chickens received an intravenous infusion of ALA (0, 25 or 50 mg/kg per h) for 90 min. Blood was drawn at 30 min intervals, and plasma glucose, NEFA, free glycerol and hydroxybutyrate were analysed. In the second experiment, ALA (100mg/kg per h) was continuously infused to chickens fed or fasted for at least 24 h. Changes in plasma metabolites for 90 min were determined. In the first experiment, as shown by the response area, ALA infusion did not affect plasma glucose but increased (P < 0.05) plasma NEFA, regardless of the dose level. In contrast, plasma hydroxybutyrate was reduced at the lower infusion rate (P < 0.05). No significant changes in plasma free glycerol were observed. In experiment 2, ALA stimulated both plasma glucose (P < 0.01) and NEFA (P < 0.001) and the responses were greater than those of controls, regardless of the feeding state. The interaction between ALA and the feeding condition had a significant effect on plasma hydroxybutyrate (P < 0.01). ALA reduced plasma hydroxybutyrate, and this response was greater in the fasted birds than in those fed. Therefore, the present study found a lowering effect of ALA on plasma hydroxybutyrate level and suggests that the ALA-induced plasma NEFA increment was attributable to decreased hepatic fatty acid oxidation in chickens.