Abstract: An experiment was conducted to investigate effects of exposure for 3 weeks to high concentration of Zn²⁺  (50 mg·L^-1) on immunochemical variation of serum and hepatopancreas in Procambarus clarkii.Antioxidative and immune parameters such as superoxide dismutase(SOD),lysozyme,acid phosphatase(ACP),and malondialdehyde(MDA) were measured.Results show that activities of SOD,ACP and lysozyme and content of MDA in serum all increased on Day 1,then turned downwards and decreased continuously with the prolonging of the exposure time,but the activities of SOD and ACP and the content of MDA were all only slightly inhibited after 21 days of exposure,but lysozyme remained higher in activity than that in the control groups.The activity of SOD in hepatopancreas was inhibited within 7 days of exposure and activated on Day 14(P<0.05),but suppressed slightly again after Day 21.Lysozyme and ACP both were activated first and inhibited later,but the inhibition effect was more significant in hepatopancreas than in serum after Day 21,indicating that hepatopancreas is more sensitive to Zn²⁺  than to serum,and Procambarus clarkii can tolerate high Zn²⁺  contamination by enhancing its immunochemical enzyme system.

Key words: Procambarus clarkii, Zn²⁺, SOD, MDA, ACP, lysozyme