Screening And Application Of Chinese Herbal Medicion Possessing Bacteriostatic Effect On Aeromonas Schubertii From Hybrid Snakehead

In recent years,with high density Hybrid Snakehead(Channa maculata♀×C. argus♂) culture systerm promotion, water quality of aquaculture in poor, the frequent occurrence of disease, restricts to sustainable and healthy development. Visceral sarcoidosis caused by Aeromonas schubertii is one of the common diseases of Hybrid Snakehead. Chinese herbal medicine commonly used as drugs in aquaculture, with the advantages of the natural property,muti-function,low-residues and abundant sources. And Chinese herbal medicine have antibacterial,enhance immunity and many more features. Therefore, use Chinese herbal medicine to improve the immunity of the fish body, reduce the occurrence of disease is an important measure to maintain sustainable development of aquaculture Hybrid Snakehead.In first trail, 60 kinds of Chinese herbal medicine was used for selecting out those who have function of restraining bacteria growth. The effective components in the crude medicine were separated by water extraction, before they were made into 1g/m L aqueous solutions.We conducted bacteriostatic tests in vitro by agar diffusion assay and the two fold dilution method, while diameter of inhibition zone and MIC was used as the evaluating indicator.The results revealed that Chinensis Gall, Rhubarb,Amur Corktree Bark,Garden Burnet Root,Flos Caryophyllata,Common Floweringquince Fruit,Medicine Terminalia Fruit,Chinese Magnoliavine Fruit, Catechu,Dark Plum Fruit, Golden Thread had better selective bacteriostatic functions.In second trail,the orthogonal t value method was applied,the agar diffusion assay was adopted to study the best compatibility of bacteriostatic effect with the diameter of inhibition zone(DIZ) as the evaluating indicator.The eleven herbs were chosen to compose prescriptions.The results indicated that formula consists of Dark Plum Fruit and Common Floweringquince Fruit;through acute toxicity test evaluated the safety of Chinese herbal prescription,the results indicated that the LD50 is not less than 8×105mg/L,and the herbal medicament was hence determined as non-toxic substance, belonging to safe medicine.Hybrid Snakehead with weight of(22.42±0.99)g and length of(15.45±1.02)cm were randomly divided into 8 groups with 3 replicates and 30 fish in each replicate in the third and the forth trails.To investigate the effect of different doses of Dark Plum Fruit and compound herb medieine in feed on the growth,Hybrid Snakehead were fed by Dark Plum Fruit and compound herb medieine at different levels of 0.5%,l%,2% respectively for 60 days.Hybrid Snakehead weight and length were tested in company at the last day.The results indicated that after the 60-day test,with the increase of the added amount, the end weight,weight gain, SGR, WGR appeared slowly decreased, the maximum occurred at 0.5% compound groups, respectively 14.93%、20.92%、22.46%、11.47%;the experimental groups are indistinct different on the effects of Form factor;but the maximum of spleen index was in 2% Dark Plum Fruit group.To investigate the effect of different doses of Dark Plum Fruit and compound herb medieine in feed on the non-specific immune,activitiesof SOD, MDA, CAT, ACP, AKP in the liver, muscle and serum. The results showed that, compared with the control group, the activity of SOD was improved and MDA was reduced in the tested organ of three compound herb medieine groups and three single drug groups; the activity of SOD in the 1% single drug group in the live and serum and the 2% compound additive group in the muscle were both significantly higher than that in the control group;the activity of MDA of 1% single drug group in the live was greatly significantly higher,0.5% compound additive group in the muscle and 2% single drug group in the muscle and serum were all signifieantly lower than that in the control group; compare with the control group, the activity of CAT in 0.5%、1%、2% compound additive groups and 2% single drug group were all improved, the activity of CAT in the single drug group 2% was greatly significantly higher in the live and serum,the activity of CAT in the compound additive group 2% was greatly significantly higher in the muscle;But the experimental groups are indistinct different on the effects of ACP and AKP in the liver, muscle and serum。The results of full test showed that adding 0.5% of Chinese herbal compound to essential feed can promote growth; it suggested that the 2% of Dark Plum Fruit is the better level when apply to enhance immunity.