Effect of salinity stress on the activities of phenoloxidase and superoxide dismutase of the serum、tissue and organ of mud crab,Scylla serrata

This paper studied the effect of salinity(5,15,25 and 35) stress on the biochemical response of Scylla serrata by enzyme analysising.Scylla serrata were acclimated in close-cycle system before transferred to different groups.Each treatment was run in triplicate.The activities of phenoloxidase(PO) and superoxide dismutase(SOD) were determined after 24~96h.The results showed that the phenoloxidase activity was increased significantly with salinity decreasing in salinty(p0.05).The serum PO activities of S5 and S15 were significantly higher than those of S25 and S35(p0.05).Each experiment group displayed certain changes except that the S15 group showed the trend of incessantly descending.Meanwhile,the SOD activity of muscle in mud crab increased significantly when transferred to 5,15 and 35(p0.05).The effect of the muscle SOD activity of Scylla serrata in the experimental group decreased with the time over 72h stress.Whereas the SOD activity in hepatopancreas of mud crabs that transferred from salinity 25 to salinity 5,15 and 35 increased.The influence of salinity stress on the SOD activity of mud crab was significant(p0.05),relative to the elapsed time.In conclusion,the effects of salinity stress on the non-specific immunity of mud crab would affect activities of PO in serum and SOD in muscle and the hepatopancreas.