Abstract: The effects of dietary lead levels on growth performance, metabolic enzyme activities in serum (ALT, AST and LDH), MDA content and antioxidant defense systems of hepatopancreas of Jian carp(Cyprinus carpio var.Jian) were investigated. Four hundred and eightythree Jian carp (average initial weight, 22.95±0.15 g) were randomly divided into seven treatments and exposed to 0, 2, 5, 10, 20, 50 and 100 mg·kg-1 concentrations of Pb in diet for 60 days. The results showed that weight growth ratio and feed conversation ratio were not significantly affected by dietary Pb (P>0.05), but weight growth ratio presented a downward trend with the increasing Pb concentrations and feed conversation ratio presented an upward trend with the increasing Pb concentrations. After long term Pb exposure, AST activity presented an upward trend with the increasing Pb concentrations, significant increase of AST activity were only found in 100 mg·kg-1 Pb group (P<0.05), ALT and LDH activities presented an upward trend with the increasing Pb concentrations, significant increase of ALT and LDH activities were found in 20, 50 and 100 mg·kg-1 Pb groups (P<0.05). The MDA content in hepatopancreas increased with the increasing Pb concentrations. SOD and GSH-PX activities were induced by dietary Pb. The dietary Pb could lead Pb concentrationdependent toxicity on Jian carp. The changes of the activities of metabolic enzyme activities in serum, MDA content and antioxidant defense systems of hepatopancreas could be used in indication of Pb contamination in diet．

Key words: Pb, growth performance, enzyme activities, Jian carp (Cyprinus carpio var. Jian)