Influence of Fish Poison Rotenone on Thyroid Activity and Metabolite Regulation in Air-Breathing Perch (Anabas testudineus Bloch)

The bark and seed of Derris plant have been used by fishermen to capture fishes, as they contain a toxic compound, rotenone, which can intoxicate fishes. In the present study, the effects of rotenone on the status of thyroid hormone and metabolites were tested in the air-breathing fish Anabas testudineus Bloch. Rotenone (1 and 5 mg L¹) exposure for 48 h produced significant reduction in serum T₃ and T₄ levels. Similarly, rotenone exposure reduced the serum T₃ and T₄ levels in thyroid hormone (TH)-pretreated fish, indicating the disruption of thyroid by rotenone. Rotenone exposure increased the serum glucose, triglycerides, urea and total liver protein in fish. On the contrary, significant reduction in LDH and aspartate aminotransferase activities in the liver and serum was found, though alkaline phosphate activity in the serum and liver, and alanine aminotransferase activity in the liver showed significant decline. A similar pattern of metabolite distribution and thyroid inhibition was also found in the TH-treated fish, ruling out the possibility of involvement of thyroid in rotenone-induced metabolite regulation. Overall, disruption of thyroid by rotenone was evident in this fish.