| Fenpropathrin, as a third-generation pyrethroid insecticides, is widely used in agriculture due to have series features such as high efficiency, low toxicity and a wide range insecticidal. Pyrethroid is highly lipophilic pesticide and highly toxic drug and it can be serious damage to the fish, shrimp and other aquatic organisms with direct access to the gills and blood in the water. The study, an experimentation about the actue and the sub-actue of carp which exposing to the different concentrations of fenpropathrin. To explore the damage and toxic effects of fish in fenpropathrin, through detecting the gill tissue of Na-K-ATPase, liver and kidney tissue SOD, CAT activity and MDA content, and observateing pathological tissue. The rusults show:1. The acute toxicity test of fenpropathrin on carpAccording to the previous trials, six concentrations (1μg/L,2μg/L,4μg/L,8μg/L,16μg/L,32μg/L) and one blank control group, each with three parallel, were setted. Sub-lethal concentration was8.53μg/L through the modified Korbor. Based on the toxicity grading standards, fenpropathrin was highlytoxic to the carps.2. The effect of fenpropathrin on the Na-K-ATPase and antioxidant defense system of carpsThe carps exposed to fenpropathrin of different concentrations (0μg/L,0.43μg/L,0.85μg/L,1.71μg/L,4.27μg/L) for21day. The gill, liver and kidney were sampled on the1,3,7,14,21days and the activity of Na-K-ATPase, superoxide dismutase (SOD), catalase (CAT) and the lever of malondialdehyde (MDA) in different tissues of carps have been detected through microplate reader.The results of the activity Na-K-ATPase in the gill of carps show that:during different exposure periods it varied as waved shape, decreased and then increased with the increasing exposing time at the same concentrations, and another downward trend followed. The activity of ATPase reached the lowest at day3, and the difference was significant compared with the control group (P<0.01), the inhibition rates were42.49%, 27.48%,59.03%,46.31%. The enzyme activity of all concentration groups were the highest at the14th day, and significantly (P<0.05) or highly significant (P<0.01) higher than that in the control group. At the21st day, the enzyme activity of the highest concentration group was significantly lower than the control group but the ather3groups were still higher than that in the control group.The results about the activity of SOD show that:in the liver of carps it was inhibited and the increased over time. The activity of SOD in low concentration groups (0.43μg/L,0.85μg/L) were inhibited to the lowest level and significantly lower compared with control groups (P<0.05or P<0.01) after3d exposed; in high concentration groups (1.71μg/L,4.27μg/L) were decreased to the lowest level and high significantly lower compared with control groups (P<0.01) after7d exposed.21d later, the activity in all the treatment groups were higher than the control group. In the kidney of carps, the activity of SOD had no clear changes in the low concentration groups (0.43kdg/L,0.85μg/L), while it tend to be increased and then inhibited in the high concentration groups over time, and the variational ranges were becoming higher with the concentration. It significantly increased to the highest level after exposed3d (P<0.01). after21d, all the treatment groups tend to be as the control group except the highest concentration group.The results about the activity of CAT show that:in liver besides exposed in0.43μg/L group it decreased significantly (P<0.01) at3d, the activity in the others were not different between with the control group; it highly significant decreased after exposed1d (P<0.01), and then to the lowest level after3d. It inhibited to the lowest level at7d and the increased rapid in groups1.71μg/L and4.27μg/L; After21d exposed, all the treatment groups were not different between with the control group. In kidney the changes of CAT activity were first increase then decrease with times went on; at1d and3d, the changes were the clearest and became to the highest level.The level of MDA show that:it both changed as time in liver and kidney. The0.43μg/L group was not significant different with control group (P>0.05). The content of MDA in liver increased rapid after7d, and then slowed. In kidney it changed at3d, and the high concentration groups(1.71μg/L,4.27μg/L) increasing went on to the21d.3. The effect of fenpropathrin on the histopathological damageThe toxicity and the effect on histomorphology of gill, liver and kidney of carps which exposed for21days in five different test concentrations (0μg/L,0.43μg/L,0.85μg/L,1.71μg/L,4.27μg/L) of fenpropathrin had been studied by watching the changes of behavior, and the pathologic examination of gill, liver and kidney which exposing for1d,3d,7d,14d,21d. The result of hematoxylin-eosin dyeing assay showed that histological changes in the gills included gill-amells distorted, epithelial cell and pillar cell droped, blood capillary of gill-amells expanded and hyperaemia, mucilage cell and basal cell hyperplasia. In the serious, gill-amells adhesion, gill filament changed club-shape. It appeared following symptoms in liver, cells hydropic degeneration, sinusoids enlargement, cytolysis in the serious. The main symptoms in the kidney of carp, renal tubular epithelial cell swelling, hydropic degeneration, renal interstitial cells increased and lymphocytic cell infiltrated, hemosiderin deposited increased, cytolysis when the high concentration group were exposed for21days. It indicated that the damage to the gill, liver and kidney is not only related to the concentration, but also the effect of time accumulation. The ultramicroscopical observation of high concentration fenpropathrin intoxicated liver cells shows that, the nuclear atrophy, the marginal heterochromatined, the mitochondria swelling, spine fracture and membrane rupture, the rough endoplasmic reticulum swelled, loosed even fratured; the microscopic observation of renal tubular epithelial cells showed, golgi apparatus swelling; organelle disintegration and liquefied make to many autophagic lysosome and mixed cyst; The nucleus disintegration, etc. |
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