Anaesthetic properties of ketamine in chicks stressed with hydrogen peroxide

Abstract

The goal of this study was to examine the effect of oxidative stress (OS) induced with hydrogen peroxide (H₂O₂) on the anaesthetic properties of ketamine in seven and 14 day-old broiler chicks. Spectrophotometric analysis revealed that H₂O₂(0.5%) induced OS through significant inhibition of glutathione (GSH) and elevation of malondialdehyde (MDA) concentrations in the brain of chicks in comparison to control (tap water) group. The hypnotic and analgesic median effective doses (ED_50s) decreased by 44% and 19%, respectively, in the stressed group compared to control group of chicks. On the other hand, the acute toxicity of ketamine increased through decreasing the acute median lethal dose (LD₅₀) (22%) in stressed chicks as determined by the up-and-down method. Injection of multiple ketamine doses at 10, 20 and 40 mg/kg, i.m. produced hypnotic effects for both groups of chicks depending on the dose, whereas H₂O₂ caused an increase in ketamine hypnotic efficacy in comparison to the control group. In the same manner, the antinociceptive effect of ketamine increased in the stressed chicks that underwent electrostimulation for pain induction. Both AST and ALT concentrations in the plasma were significantly elevated in the stressed group when compared to the control group. The results of this study suggest that H₂O₂-induced OS modifies the anaesthetic properties of ketamine in chicks by increasing its efficacy and acute toxicity probably through its pharmacodynamic and pharmacokinetic interactions; thus, care must be taken when stressed animals are undergoing anaesthesia with ketamine.