Effects Of Supplemental Different Level Vc, Ve And Schizochytrium On Non-specific Immunity Of Chinese Shrimp (Fenneropenaeus Chinensis)

Vitamin C and vitamin E are two immunopotentiators applied widely in the aquatic animal health cultivation. Schizochytrium is a Marine fungi , rich in unsaturated fatty acid .In order to providing new thinking for immune mechanism of vitamin, the genes related to immune response signaling pathway and the immune path the two kinds of vitamin were researched in this paper. The Chinese shrimp was used for experimental object in this experiment. The effects of the nonspecific immunity factors and TLR and NF-κB mRNA expression of Chinese shrimp at different concentrations of vitamin C and vitamin E were researched in this paper. The research was divided into two parts:The Chinese shrimp was used for experimental animal in this experiment in the first part. We fed different leVels (0%,0.5%,1%,2%) of Vc to study the influence on the Chinese shrimp.After 1, 3, 6, 9, 12 and 15 days, We sampled and detected survival rate and activity of inducible nitric oxide synthase (iNOS), catalase (CAT), total superoxide dismutase (T-SOD) and lysozyme (LZM), taking which as immune indexs, the nonspecific immunity effects at different concentrations were inVestigated in this paper. We also used real-time fluorescent quantitatiVe PCR (RT-PCR) to examine the expression TLRs and NF-κB genes in the Chinese shrimp. Results showed that: (1) Comparing to control group, all Vc groups could raise the survival rate. The 1% group showed the highest survival rate among groups,with survival rate at 90.28%, significantly higher (P<0.05) than that of other groups. All Vc groups could raise the activity of iNOS,CAT and LZM at some degree and 1% group showed the best immune activating effects among groups. All Vc groups also could raise the activity of T-SOD, 1% group showed the best immune activating effects on T-SOD in serum ,the SOD activity in the gills, muscle and hepatopancreas of the Vc group of high concentration, especially the hepatopancreas, showed higher than that of other groups.In a word, the survival rate and the activity of nonspecific immunity enzyme were the best in the 1% Vc group. (2) RT-PCR showed that, Vc had up-regulatory activity on mRNA expression of TLR and NF-κB. 1% Vc group had the most significant up-regulatory activity on mRNA expression of TLR in the serum. And 0.5% Vc group was in the next. The up-regulatory activity of Vc on mRNA expression of TLR in the gill was related to concentration of Vc. The leVels of mRNA expression of TLR were 2% group>1% group>0.5% group. The mRNA expression of TLR was inhibited in the 1% group and 0.5% group, though, which was inhibited first and then promoted and reached the maximum after 12 days which was 6.87 times of control group. 2% Vc group had down-regulatory activity on mRNA expression of TLR in the muscle. The mRNA expression of TLR of 1% group and 0.5% group showed inhibition first and then promotion. The leVels of TLR and NF-κB mRNA expression in the tissue were different. 0.5% and 2% Vc group both had down-regulatory activity on mRNA expression of TLR and NF-κB in the four tissue. NF-κB mRNA expression in the serum and muscle of 1% group is higher than that in other groups. HoweVer, the actions in the gill and hepatopancreas of the 1% group were on the contrary.The Chinese shrimp was also used for experimental animal in this experiment in the next part. Different concentrations Ve and Schizochytrium were added into basic feedstuff. There were 5 groups, including B group(10% Schizochytrium), C group(200 mg/kg Ve), D group(400 mg/kg Ve), E group(600 mg/kg Ve), and F group(400 mg/kg Ve + 10% Schizochytrium). The A group (basic feedstuff) was control group. The experiment lasted 1 month. After 1, 15 and 30 days, we sampled and detected body weight and length. The death rates and survival rates were checked eVeryday. The activity of inducible nitric oxide synthase (iNOS), total superoxide dismutase (T-SOD), lysozyme (LZM), malondialdehyde (MDA) and glutathione (GSH) were taked as immune indexs to inVestigate the nonspecific immunity effects at different concentrations of Ve. The real-time fluorescent quantitatiVe PCR (RT-PCR) was used to examine the expression TLRs and NF-κB genes in the Chinese shrimp. The results showed that: (1)Comparing to control group, all Ve groups could promote the increase of body weight and length, which of D group was higher than C group and E group while obviously lower than F group. The higher concentration of Ve, the higher survival rate. The survival rates of E group and F group were significantly higher than that of other groups, which indicated that Ve is beneficial to growth and survival rate of the Chinese shrimp. There was no significantly different between A group and B group about the nonspecific immunity enzyme. HoweVer, the nonspecific immunity enzyme of F group was significantly higher than that of B group. (2) The mRNA expression of TLR was inhibited by Ve in the muscle and hepatopancreas. Comparing to control group, 200 mg/kg Ve group could reduce the leVel of TLR on serum and other groups had up- regulatory activity , 200 mg/kg Ve group had down-regulatory activity on mRNA expression of NF-κB in the three kinds of tissue. For A, B, D and F group, the tendency of TLR mRNA expression in the muscle was the same as that of hepatopancreas, whose order of expression leVel was A>B>D>F. And the tendency of NF-κB mRNA expression in the serum was the same as that of hepatopancreas, whose order of expression leVel was B>A>D>F.It indicated that increasing some Schizochytrium in the feedstuff would reduce leVels of NF-κB and TLR mRNA expression. Combining Ve and Schizochytrium could more effectiVely improVe the regulation of immune genes.