Abstract:The effects of different concentration of fenvalerate on the activity of superoxide dismutase(SOD),content of malondialdehyde (MDA) in serum and liver and histomorphology of liver and kidney of common carp were studied.The results indicated that in the serum and liver,the activities of SOD in the treatment groups increased first,then decreased,and the activity of SOD in the serum incresed earlier than that in the liver.The activities of SOD in the experimental groups were all significantly lower than that in the control group after exposure in fenvalerate for 21 d ( P <0.01).The content of MDA was significantly increased with the increase of exposing time,especialy between 3 and 14 d after exposure.The result of HE stain dyeing showed that in the liver,hepatic sinusoid dilated and congested,liver cell denatured and dissolved,and even worse,local necrosis appeared,which were more noticeable after exposure in 0.8 μg/L fenvalerate for 21 d and in 4.05 or 20.25 μg/L fenvalerate for 3 d.In the kidney of common carp,renal interstitial cells increased,lymphocytic cell infiltrated,some basement membrane separated from renal tubular,and renal tubular cells hydropic degenerated.The glomerulus shrunk and a large amount of hemosiderin deposited in the high concentration group after exposure for 21 d.The ultramicroscopical observation of liver cells after exposure in high concentration fenvalerate for 21 d showed that the marginal heterochromatined,the rough endoplasmic reticulum swelled,loosed and fratured and lipid droplets increased.The above damage was not only related to the concentration,but also had time accumulative effect.