尿素对中华绒螯蟹幼蟹非特异性免疫功能的影响

Impact of urea on non-specific immune response of juvenile Eriocheir sinensis

分别用0.24、0.48、0.72、0.96、1.20g/L的尿素溶液饲养中华绒螯蟹幼蟹7d,测定幼蟹血清中超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化氢酶(Catalase,CAT)、谷胱甘肽-S转移酶(Glutathione-S transferase,GST)的活性和丙二醛(Malondialdehyde,MDA)的含量。结果表明,随着时间的延长,各浓度组中华绒螯蟹幼蟹血清中上述3种酶的活性逐渐下降,丙二醛含量逐渐上升;随着浓度的增加,3种酶活性有逐渐下降的趋势,但0.24g/L尿素浓度组中华绒螯蟹幼蟹血清中超氧化物歧化酶活性和0.96g/L浓度组中华绒螯蟹幼蟹血清中谷胱甘肽-S转移酶活性显著高于其他处理组,这两组中华绒螯蟹血清中丙二醛含量则相应下降。表明尿素浓度增加使得中华绒螯蟹幼蟹体内清除脂质过氧化物、过氧化氢和自由基的能力下降,对中华绒螯蟹幼蟹体内的非特异性防御系统有损伤。

Urea is an important factor for paddy production in paddy-crab ecosystem.However,application of urea may impose negative effects on the growth of crabs.In our research,the effects of different concentrations of urea on the non-specific immune system of juvenile Eriocheir sinensis were studied in order to provide necessary theoretical support for setting up regulations for the paddy-crab ecosystem.The juvenile E.sinensis were reared in water containing 0.24,0.48,0.72,0.96,and 1.2 g/L urea respectively for 7 days without feeding.The activities of three enzymes including superoxide dismutase（SOD）,catalase（CAT）,and glutathione-S transferase（GST）,as well as the content of malondialdehyde（MDA）in crab serum were determined.The results showed that the activities of SOD,CAT,and GST decreased gradually in crab serum for all urea concentrations during the experimental period,while the content of MDA increased instead.Also the activities of the above three enzymes showed a decreasing tendency as the urea concentration increased.However,the SOD activity in 0.24g/L and the GST activity in 0.96g/L urea treatments were significantly higher than those in the other urea-treated groups,while the content of MDA in these two treatments decreased.The results suggest that the added urea reduces the E.sinensis＇s capability of eliminating lipid peroxides,hydrogen peroxide and free radicals.As a result,the non-specific defense system was damaged with the application of urea.