Effects Of Three Kinds Of Medical Herb Extraction On Non-specific Immunology And Disease Resistance Of Gibel Carp Against Aeromonas Hydrophila Infection

Chinese herbal medicines and their active compounds are characterized by naturalness,low toxicity and side effects,and low drug resistance.It not only has good antibacterial effect,but in addition can enhance the immunity of fish and reduce the risk of fish disease.In this paper,three medical herb extractions were selected for antibacterial infection experiments.Resveratrol(RES)has many pharmacological functions such as anti-oxidation,inflammatory immune regulation,lipid metabolism regulation,anti-virus.Curcumin(CUR)has the functions of lowering blood fat,anti-inflammatory and anti-oxidation.As a plant polysaccharide,Scutellaria baicalensis polysaccharide(SBP)has antioxidant activity,can increase the body’s immune function,affect cell division and differentiation,and promote antibody production.Aeromonas hydrophila belongs to Gram-negative bacteria and is widely found in fresh water,sewage and soil.In the production,it is found that there are many diseases caused by Aeromonas hydrophila,and the diseases infected by the bacteria are mostly malignant infectious diseases,and the mortality is high.We constructed a model of Aeromonas hydrophila infection by intraperitoneal injection.After drug treatment,the mortality was counted,plasma and liver samples were collected for blood biochemical indicators and liver antioxidant function analysis.In addition,the expression of antioxidant and immune related genes in the liver was detected by real-time PCR.The main results are as follows:1.In the monomer experiment,the mortality rate of all drug treatment groups was lower than that of the control group,and the 0.5‰ SBP group have the highest relative percent survival(RPS)of 45%;the immunoglobulin G(IgG)content of the drug-treated group was significantly higher than that of the control group(P<0.05),and the content of complement component 3(C3)in the 0.5‰ SBP group was significantly higher than that in the control group(P<0.05).The content of malondialdehyde(MDA)in the 5.0‰ RES group was significantly lower than that in the control group(P<0.05).In the drug-treated groups,the antioxidant-related genes CAT,SOD,GSTA and the immune-related genes IL-10,IL-1 were significantly lower than those in the control group and the antibiotic group(P<0.05).The research findings demonstrated,when gibel carp are infected by Aeromonas hydrophila,feeding them with medical herb extraction all can reduce their mortality,improve their immune function and antioxidant capacity,and the effect of adding 0.5‰SBP to the feed is most significant.2.In the compound experiment,the mortality of three experimental groups(0.2‰ RES+2.5‰ CUR+0.5‰ SBP,1.0‰ RES+0.1‰ CUR+0.1‰ SBP,5.0‰ RES+2.5‰ CUR+0.1 ‰ SBP)significantly lower than the control group(P<0.05),and the RPS reached 63.16%;Blood biochemical indicators showed that the IgG content of Group 9(5.0‰ RES+2.5‰ CUR+0.1‰ SBP)was significantly higher than that of the control group(P<0.05),and the TP and ALB content of Group 3(0.2‰ RES+2.5‰CUR+0.5‰ SBP)and Group 4(1.0‰ RES+0.1 ‰CUR+0.1‰ SBP)were significantly higher than the control group(P<0.05).The liver antioxidant index showed that the MDA content of each experimental group did not change significantly compared with the control group(P>0.05).According to fluorescence quantitative analysis,the relative expression levels of antioxidant-related genes CAT of Group 4(1.0‰ RES+0.1‰ CUR＋0.1‰ SBP)were significantly higher than the control group(P<0.05),and the relative expression levels of immune-related genes IL-10 and TNF-α in Group 9(5.0‰ RES+2.5‰ CUR+0.1‰ SBP)were significantly higher than those in the control group(P<0.05).The results showed that the combination of 0.2‰ RES,2.5‰ CUR and 0.5‰ SBP was the most effective,the mortality was significantly reduced,and the antioxidant capacity and immune function were significantly enhanced in this experimental group.