The Immune Regulation Of Astragalus Polysaccharides On Paramisgurnus Dabryanus

Current researchs and applications about immunostimulant effect on Paramisgurnus dabryanus were less reported. It was a great significance for establishing immunosuppression model and research and development of natural immune enhancer to loach ecological farming and the immune prevention of disease of loach.In this paper, taking cyclophosphamide(CYP) as immunosuppressant was order to form Paramisgurnus dabryanus immunosuppression experimental model method, and to study the immune regulation of Astragalus polysaccharides(APS) on immunosuppressive Paramisgurnus dabryanus on the basis of the effect of APS on the healthy Paramisgurnus dabryanus.The result s of the experiment were as follows:1.We fed Paramisgurnus dabryanus with the basal feed added the different doses of APS(0,50,100,200,400 mg/kg) for 28 days, sampled the blood and hepatopancreas at the beginning of 7,14,21,28 day respectively and tested the effect of APS on Paramisgurnus dabryanus’ s non-specific immune function. The results showed that the groups of 50~400 mg/kg APS significantly increased the total hemocyte counts(BRC and WRC), the acticity of acid phosphatase(ACP), alkaline phosphatase(AKP) and lysozyme(LSZ) in serum, the activity of catalase(CAT) and the tatal superoxide dismutase(T-SOD) in hepatopancreas(P<0.05),and reduced the activity of the glutamic oxalocetie transaminase(GOT), glutamic pyruvic transaminase(GPT) and the content of MDA in hepatopancreas(P<0.05); The groups of 50、100 mg/kg APS had a significantly enhanced effect on C3 activity in serum(P<0.05); The content of NO of 50 and 100 mg/kg APS groups in serum were higer than the control group at the first week and the second week of feeding respectively, but the serum NO levels of 50, 100 and 400 mg/kg groups at the third week, and the serum NO levels of 50 and 100 mg/kg groups at the fourth week were significantly lower than control group(P < 0.05). In general, 50~400 mg/kg APS were relatively appropriate levels of feed additives. But according to the effect and the principle of small dose, it suggested to add 50 mg/kg APS in feed when used to prevent disease happening and improve body immunity.2. We used the different doses of CYP(0, 100, 200, 300 mg/kg weight) to suppress the immunity of Paramisgurnus dabryanus by peritoneal injection only for one time. Blood and hepatopancreas samples were collected at the first 4, 8, 12, 16 days after injection for testing BRC、WRC、LSZ、ACP、AKP、NO、C3 activity in serum and SOD activity 、 MDA content in hepatopancreas.The results showed that the three concentration groups of CYP could reduce BRC,WRC,the activity of LSZ, AKP, ACP in serum and the content of C3 in serum, increase the content of NO in serum and the content of MDA in hepatopancreas significantly(P<0.05).As well as the effect of immunosuppression was the best on the eighth day of injection. Therefore, CYP could be used to build immunosuppression model of Paramisgurnus dabryanus. Considering the CYP effect and cost, the dose of 200 mg/kg body weight was suitable.3. Paramisgurnus dabryanus was fed with the basal feed respectively added the 0(control group)、0(model group)、100、200、400 mg/kg of APS for 28 days,then we used 200 mg·kg-1 of CYP body weight to inject Paramisgurnus dabryanus in the fifiteenth day, and the control group were injected the same amount of 0.85% saline. On the first 4, 8, 12 days after injection, sampling the blood and hepatopancreas was to test the Paramisgurnus dabryanus’ non-specific immune response each group. Experimental results indicated that the WBC,LSZ, ACP and AKP activity in serum, CAT activity and T AOC in hepatopancreas of model group were significantly lower than the control group on the 4, 8 and 12 days after the injection of CYP(P < 0.05). The LSZ, ACP and AKP activities in seeum and T-AOC in hepatopancreas of 100, 200 and 400 mg/kg of APS groups almost were significantly higher than that of model group(P < 0.05). The pancreatic liver MDA content of model group was significantly increased than the control group(P < 0.05), the pancreatic liver MDA content of 200 mg/kg APS group was significantly lower than that of model group on the 4 and 8 day after injection of CYP(P < 0.05). The RBC and the content of serum complement C3 in model group were both significantly lower than that of control group, but that of 100 and 200 mg/kg APS were significantly higher than the model group on the 8 day after the injection of CYP(P < 0.05). On the 4 day after the injection of CYP, the WBC of 100、200 and 400 mg/kg APS groups were significantly higher than that of model group(P < 0.05). Thus it could be seen that CYP successfully induced immunosuppression of Paramisgurnus dabryanus, and APS had obvious regulation effect on the immune function and antioxidant capacity of Paramisgurnus dabryanus, and it was appropriate to add 200 mg/kg APS in feed when confronted with diseases and decreased immunity.