| Beta-cypermethrin, a type Ⅱ pyrethroid insecticide, is widely used in agriculture around the world. Although much research on the toxicity of beta-cypermethrin has been done in fishes, little is so far available regarding its toxicity to crustaceans, such as shrimp, crab and crayfish. To investigate the acute toxic effect of beta-cypermethrin on Procambarus clarkii, the crayfishes were exposed to various concentrations of beta-cypermethrin（0 μg·L-1, 0.005 μg·L-1, 0.01 μg·L-1, 0.02 μg·L-1 and 0.04 μg·L-1） until 96 h according to the 96 h LC50 values（0.2 μg·L-1） measured previously. Activities of antioxidant enzymes viz. superoxide dismutase（SOD） and catalase（CAT）, and contents of malondialdehyde（MDA） in gill, hepatopancreas and serum were determined at 24 h, 48 h, 72 h and 96 h, respectively. Results indicated that SOD activities first increased then declined in different tissues during the 96 h exposure, and that CAT activities showed the similar trends. MDA contents in all treatments were higher than those in the control group at all the time and they increased with the exposed time and concentration increasing. After 96 h, the activities of SOD in hepatopancreas, gill and serum at 0.04 μg·L-1 treatment decreased by 28.3%, 44.1% and 27.2%, compared with control group, respectively. Similarly, the activities of CAT in different tissues decreased by 38.1%, 39.4% and 12.3%, respectively. MDA contents in hepatopancreas, gill and serum were 0.72 times, 1.09 times and 0.46 times higher than those in the control group, respectively. This study showed that beta-cypermethrin was able to induce oxidative stress and had significant negative effects on antioxidant enzyme activities of Procambarus clarkii. |
