Malathion toxicity: effect on the liver of the fish Brachydanio rerio (Cyprinidae).

Four-month-old siblings of zebra fish, Brachydanio rerio, were exposed to 0.5, 0.7, 0.9, and 1.1 mg/liter of malathion for 7 days. DNA, RNA, protein, and free amino acid contents and the activities of acid and alkaline phosphatases were monitored in the liver. There was marked inhibition in DNA, RNA, and protein contents and the activities of acid and alkaline phosphatase. Total free amino acid content, however, significantly increased. Seven days withdrawal to freshwater indicated a recovery trend. The probable reasons for various changes are discussed.