Effects of supplemental different level Vc on survival and non-specific-immunity of Chinese shrimp(Fenneropenaeus chinensis)

In order to deeply understand the immune function of Vc,we fed different levels(0%,0.5%,1%,2%)of Vc to study the influence on the Chinese shrimp.We detected survival rate and activity of iNOS,CAT and LZM at the different experiment times of Chinese shrimp.Using real-time fluorescent quantitative RT-PCR approach,expression TLRs and NF-κB genes were examined in serum and gills of the Chinese shrimp.Results showed that:(1) VC can raise the survival rate and the activity of iNOS,CAT and LZM.The 1% groups show the best immune activating effects among groups,with survival rate at 90.3%,significantly higher(P<0.05)than that of other groups.(2) Vc has regulatory activity on mRNA expression of TLR and NF-κB.There are significant differences(P<0.05)on TLR expression in the serum and gill of 1% group compared to the control.NF-κB mRNA expression in serum of 1% group is higher than that in other groups,but that in 2% group has the highest levels in early six days,and then declines even lower than the control.NF-κB mRNA expression in gill of 2% group is higher than control.Overall,these results demonstrate that Vc can effectively improve the survival rate and the activity of three non-specific immunity enzymes of the Chinese shrimp and regulate the expression level of TLRs and NF-κB.