Effect of waterborne copper on the microstructures of gill and hepatopancreas in Eriocheir sinensis and its induction of metallothionein synthesis

Effects of different waterborne copper concentrations (0.00, 0.01, 0.10, 1.00, and 5.00 mg/l) on microstructures of gill and hepatopancreas, and in inducing metallothionein (MT) synthesis were studied in Chinese mitten crab Eriocheir sinennsis. The results indicated that copper accumulation caused histologic damage to gill and hepatopancreas and induced MT synthesis in hepatopancreas. No significant differences were found in microstructures between 0.01 mg/l copper treatment and the control group. Exposure to copper concentrations ranging from 0.1 to 5.0 mg/l for 10 days resulted in irregularly thickened lamella, enlarged haemocoels, increased hemocytes, and damaged or disassembled epithelia in gill. Similarly, in hepatopancreas, the spaces of the small blind tubules decreased, and nuclei of the epithelia were karyopycnosised or karyorhexised. Also, the basement membranes were rumpled or even ruptured, with new vacuoles formed between the basement membrane and the simple columnar epithelia. MT measurements showed no significant differences in MT contents between the control group and the group treated with 0.01 mg/l waterborne copper. Maximum MT content was observed at the treatment level of 0.10 mg/l waterborne copper.