Neurotoxicity of xylazine in chicks

Despite the widespread use of xylazine in veterinary medicine, studies on its neurotoxicity are limited. So, our current study aims to reveal its neurotoxicity in chicks by determining the (LD50) of xylazine in Dixon's procedure. Moreover, it aims to study the effects of a small and repeated dose of xylazine on neurobehavioral test and the toxic doses of xylazine on the concentration of (glycine and glutamate) in the plasma of chicks and on the brain tissue after 60 and 90 minutes of injection. The LD50 of xylazine by injection into the chest muscle was 26.65 mg/kg. The injection of xylazine at a dose of 3 and 6 mg/kg in the chest muscle for three consecutive days caused an inhibition in motor activity within the open field as well as a significant elevation in the tonic immobility test response, injection of xylazine at doses 48.96 mg/kg ,60 and 90 minutes after the injection led to a significant increase in the glycine concentration as well as a significant decrease in glutamate after 90 minutes in the plasma of chicks, accompanied by histological variation in the brain tissue characterized by necrosis of neurons, vasogenic edema, neurophagia, cavities, infarction, necrosis of Purkinjean cell with decrees in the number of it. Our results revealed that xylazine had neurotoxic effects in chicks, represented by inhibition of neural behavior and motor activity within the open field, accompanied by a change in the concentration of glycine and glutamate in the plasma of chicks and histological variation in the brain tissue of chicks