Acute neurotoxicity of acetaminophen in chicks

Acetaminophen is a non-steroidal drug used as an anti-inflammatory, analgesic and antipyretic in humans and animals. In chicks, neurotoxicity associated with acetaminophen has not been fully elucidated. The aim of this study was to identify the neurobehavioral, biochemical and histopathological effects of acetaminophen in 7 day-old broiler chicks. The acute LD50 of acetaminophen was estimated by the up- and- down method, and then the influence of acetaminophen on the open field activity and tonic immobility test was recorded. The behavioral signs and toxicity scores were recorded. The liver enzymes, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were estimated. Histopathology of the brain and liver were performed. The acetaminophen LD50 value in chicks was 1077 mg/kg, intramuscularly. Acetaminophen reduced the general locomotive activity of the chicks, measured in the open- field arena, as a result of a significant rise in latency in moving from the central square, and a reduction in the numbers of lines crossed as well as reduction in the vocalization score compared to the control. Intramuscular injections of acetaminophen at doses of 500 and 1000 mg/kg induced signs of toxicosis, such as head dropping, closed eyelids, immobility, loss of vocalization, and recumbency, followed by death. Histopathological examination of the brain showed the presence of congestion of blood vessels, vasogenic edema and necrosis of Purkinje cells. Degenerative changes and liver enzyme function showed liver dysfunction. Our results show behavioral, biochemical and histopathological data demonstrating that acetaminophen at high doses produced acute neurotoxicity in chicks.