The change on the activity of lysozyme in hepatopancreas and kidney of grass carp exposed to different concentration of beta-cypermethrin was researched.The concentrations of the 5 group samples of beta-cypermethrin used in the experiment were 0 μg/L,0.5 μg/L,1.0 μg/L,3.0 μg/L and 5.0 μg/L respectively.The first day,fifth day and twelfth day of each group of beta-cypermethrin were utilized to determine the activity of hepatopancreas and kidney lysozyme.Results showed that all groups of hepatopancreas LSZ ac...