Effect of Tributyltin, Cadmium, and Their Combination on Physiological Responses in Juvenile Grass Carp.

Tributyltin (TBT) and cadmium (Cd) are two common pollutants in aquatic environments. This study was designed to examine the physiological responses of juvenile Grass Carp Ctenopharyngodon idella to TBT, Cd, and their combination. Fish were apportioned into a control group, a TBT group (7.5 μg/L), a Cd group (2.97 mg/L), and a TBT-Cd group (7.5 μg/L TBT, 2.97 mg/L Cd(2+)) for 7 d. The following activities were measured: Na(+),K(+)-ATPase in gill tissues; nitric oxide synthase (NOS), acetylcholinesterase (AChE), and monoamine oxidase (MAO) in brain tissues; and lipid peroxidation (LPO), malondialdehyde (MDA), total antioxidative capacity (T-AOC), and glutathione (GSH) in liver tissues. Cadmium-induced stress was suggested by alterations in antioxidant responses (MDA, LPO, and T-AOC) and neurological parameters (AChE, MAO, and NOS). Cadmium also induced Na(+),K(+)-ATPase and GSH activity. Compared with the responses among the Cd group, the combination of TBT and Cd not only decreased the level of GSH and Na(+),K(+)-ATPase but also increased the levels of MDA, LPO, AChE, MAO, and NOS. These results suggest that a combination of TBT and Cd could reduce the adverse effects of Cd on Grass Carp. However, the exact mechanisms for the combined effects TBT and Cd on these biomarkers require further investigation. Received September 28, 2015; accepted April 17, 2016.