Comparison of Lysozyme and Antibacterial Activity among Different Tissues and Organs of Carassius auratus in Qihe River

Carassius auratus in Qihe River,a natural triploid crucian carp,is an important commercial fish. To understand its antibacterial ability in various tissues and organs will be useful for preventing disease. In this study,lysozyme and antibacterial activities were measured in different tissues and organs of C. auratus in Qihe River. The results showed that lysozyme and antibacterial activities in various tissues and organs were different. The measured values of lysozyme activities were: hepatopancreas > kidney > gill > brain > intestine > spleen. Antibacterial activities were shown by the order of hepatopancreas > kidney > brain > gill > intestine > spleen,with significant difference among them( P < 0. 01). Antibacterial activities in hepatopancreas and kidney were significantly higher than those in other tissues and organs,and the activity was significantly higher in hepatopancreas than in kidney( P <0. 01). The antibacterial ability in kidney and gill was significantly higher than that in spleen( P <0. 01). The research indicates there is difference in lysozyme and antimicrobial activity among the various tissues and organs of fish,which is resulted from the different physiological function of various tissues and organs. At the same time,it is suggested that different tissues and organs play different roles in the intervention process of pathogenic bacteria in fish.