Effects Of Baicalin And Astaxanthin On Nonspecific Immunity Enzyme Of Fenneropenaeus Chinensis

Shrimp culture industry experienced a sharp decline after 1993 in China which has been rapid developed worldwide scince the sixties of last century. With the efforts of government, researchers and farmers, China becomes to be the biggest shrimp culture country in the world again. But many problems also hide behind the brilliant achievements, such as serious degradation of seed quality, physical weakness of shrimp seed, short of resistance to disease. Although the survival rate of shrimp can be improved by improving germplasm and optimaling farming techniques, the most effect way is to enhance the immune function of shrimp. Immunostimulants can help enhance the immune function and resistance to disease. Currently, many plant extracts which have the merit of low toxicity, low pollution and no drug resistance have been used to the disease controlling of many aquatic animals. In this study, effects of two plant extracts on nonspecific immunity enzyme and immune-related genes of Fenneropenaeus chinensis were analyzed by test of shrimp culture and bacteria toxin attack. The study consists of three parts:The aim of the first part was to research the baicalin on immune enzymes and metabolism of detoxification of shrimp Fenneropenaeus chinensis. Four treatments were designed with different concentrations of baicalin (0g·kg^-1, 50mg·kg^-1, 100mg·kg^-1, 150mg·kg^-1) mixed with the raw diet, and the diets were orally fed to healthy Fenneropenaeus chinensis. The activities of acid phosphatase (ACP), catalase (CAT), induced nitric oxide synthase (INOS), lysozyme (LSZ), superoxide dismutase (SOD) in haemolymph, hepatopancreas and muscle were assayed on days 1, 3, 5, 7, 9 and 11. The data indicated that activities of ACP, INOS, SOD in the group of 100mg·kg^-1 and 150mg·kg^-1 increased significantly (P<0.05) compared to the control level after feeding, and achieved the highest level in three days. All activities in the group of 50mg·kg^-1 were not significant higher than those in control (P>0.05), while activities of LSZ in heamolymph are very significant (P<0.01) in the group of 50mg·kg^-1, 100mg·kg^-1 and 150mg·kg^-1 compared to the control level at the same period. The activities of ?ACP and CAT changed most greatly in hepatopancreas, followed by muscle and hemolymph; and the activities of INOS, LSZ, SOD changed most greatly in hemolymph followed by muscle and hepatopancreas, and the middle level group and high level group reduced significantly (P<0.05) below the control level. Results of infected test showed that the artificial infection with V.anguillarum caused mortality in all groups, but the mortality of the control group was the highest and the mortality of middle dose was the lowest.The baicalin elevated the protective rate of Fenneropenaeus chinensis infected with V.anguillarum.The results showed that baicalin could regulate the immune system of Fenneropenaeus chinensis significantly, enhance non-specific immune function, disease resistance and depress the susceptivity of Fenneropenaeus chinensis efectively. All these results would provide a theoretical basis for preparation of compound Chinese herbal medicine.The results of the second part show that: Three groups of baicalin significantly inhibited mRNA expression of toll-like receptor in muscle, hepatopancreas and hemolymph of Fenneropenaeus chinensis. Baicalin may inhibit the activity of NF-KB which becomes to be the key to inhibit inflammation and its secondary inflammatory response. It can be speculated that baicalin can indirectly inhibit the mRNA expression of TLR genes which inhibited the innate immune system to produce inflammatory cytokines, increased phagocytic capacity relatively and raised the ability of killing natural immune cells.Different concentrations of astaxanthin and Schizochytrwm sp affect Fenneropenaeus chinensis in the second part. Then activity of serum, hepatopancreas, muscle and gill were detected. The result shows that:(1) Compared with the control group, protein content in serum, muscle and gill increased significantly, while little change in hepatopancreas. Protein content in high group was higher than other groups which were divided in low, medium and high concentration.(2) Astaxanthin and Schizochytrwm sp have significant dose effect on SOD activity in serum of Fenneropenaeus chinensis. High concentration group of astaxanthin was significantly higher than the contral group when astaxanthin was feed alone. SOD activity in the mixed feeding group was significantly higher than the group which astaxanthin was feed alone. SOD activity showed a significant upward trend in all the groups and its influence has significant dose effect.(3) No matter in mixed feeding group or in independent feeding group, CAT enzyme activity which were promoted in all the detected tissue was higher than the control group. CAT enzyme activity in mixed feeding group was significantly (P <0.05) to the group in which astaxanthin was feed alone. And the mixed feeding group E achieved the highest level in 10 days. CAT activity of hepatopancreas mixed feeding group F achieved the highest level in 20 days and to be 27 times to the group C which was fed astaxanthin alone. Mixed feeding group D and F showed the effect of promotion and dose effect to CAT activity in musle. Mixed feeding group and independent feeding group showed the effect of promotion overall, but the difference was not significantly.(4) Different concentration in groups of astaxanthin and Schizochytrwm sp showed different inhibition on serum of Fenneropenaeus chinensis. MDA activity of serum was firstly on the rise and fell off in the next in the group of astaxanthin independent feeding group, which had been declining in the group of mix-fed group. The downward trend had no relationship with the dose. MDA activity in hepatopancreas and gill was significantly inhibited by the feeding of astaxanthin in each group, which showed a decreasing trend over time. MDA activity in musle was inhibited in the whole process, and the higher the concentration of astaxanthin greater the inhibition in the late.