Research On Screening Compounds Of Herbs And Antibiotics For Prevention And Treatment Of Tilapia Streptococcus Disease

Streptococcus agalactiae(SA)is one of the important pathogens of tilapia,with high morbidity and high mortality characteristics,caused huge economic losses to the development of tilapia aquaculture,become the bottleneck of the healthy and sustainable development of the tilapia aquaculture.At present,antibiotics such as sulfanilamide grou are frequently used to prevention and cure of SA,However,antibiotic drugs carry the risk of drug resistance and drug residue,so it is severely limited.Chinese herbal medicine that multi component multi target cooperative interaction have some advantages of Not easily cause resistance,green and low toxicity,widely used in the prevention and treatment of diseases in aquaculture.However,The Chinese herbal medicine has a slow onset,which has a bad effect on the treatment of most acute diseases,so its application has been restricted in the prevention and treatment of aquaculture diseases.Use of Chinese herbal medicine combined with antibiotics that under limit,that can set the advantages of both and make up for their own shortcomings,is considered One of the most promising means of disease control in aquaculture.In this paper,preliminary studies caulis spatholobi extract that has been screened with good resistance to the activity of Streptococcus.On the basis of this,the agar diffusion method(included in<People's Republic of China Veterinary Pharmacopoeia>)was used to detect the activity of 9 kinds of antibiotics in different types of antibiotics,draw the standard curve between the concentration logarithm that caulis spatholobi extract and antimicrobial activity of antibiotics and the diameter of the inhibition zone,make the reasonable design of the extract and antibiotic compound solution of caulis spatholobi,and calculate the diameter of the inhibition zone when the additive effect of each compound.According to the standard,the extract of caulis spatholobi and antibiotics have synergistic antibacterial effect when the antibacterial circle diameter is larger than the range.Using the Box-behnken experimental design combined with response surface analysis to optimize the best proportion of caulis spatholobi extract and antibiotics,and using the gradient dilution method respectively of caulis spatholobi extract,antibiotics and Chinese-Western Medicine minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC).Results show that the oxytetracycline,tetracycline hydrochloride,chlortetracycline hydrochloride 3 kinds of tetracycline antibiotics and gentamycin sulfate,sulfuric acid neomycin,streptomycin sulphate 3 kinds of aminoglycoside antibiotics,with anti-streptococcus agalactiae activity.The extract of caulis spatholobi and streptomycin sulfate has a synergistic activity against streptococcus agalactiae.Response surface optimization to obtain caulis spatholobi extract and the best ratio of compound streptomycin sulphate was 42.5:1(m:m).Caulis spatholobi extract,streptomycin sulfate and their compound,the minimum inhibition concentration(MIC)and minimum bactericidal concentration(MBC)were 27.84 mg/ml and 32.48 mg/ml,0.66 mg/ml and 0.66 mg/ml,5.95 mg/ml + 0.14 mg/ml and 16.15 mg/ml + 0.38 mg/ml.Using the agar diffusion method were used respectively to determine caulis spatholobi extract,streptomycin sulfate and their compound on Staphylococcus aureus,Streptococcus agalactiae,streptococcus iniae,Micrococcus luteus 4 strains of gram positive bacteria and Vibrio natriegen,Vibrio vulnificus,Vibrio alginolyticus,Vibrio harveyi,Vibrio parahaemolyticus,d31 Escherichia coli,Pseudomonas fluorescens,Slow Edward's bacteria,Morganella morganii,Pseudomonas aeruginosa and E.coli 11 strains of gram-negative bacteria antibacterial activities,at the same time using the gradient dilution method respectively to determine the compound strains of MIC and MBC of the above.The results showed that:0.24mg/ml streptomycin sulfate have antibacterial activity to 4 strains of gram positive bacteria and 7 strains of gram-negative bacteria that In addition to Vibrio natriegen,Vibrio vulnificus,Vibrio harveyi,Vibrio parahaemolyticus and Escherichia coli;27.84mg/ml caulis spatholobi extract have antibacterial activity to 3 strains of gram positive bacteria that in addition to Micrococcus luteus and 5 strains of gram-negative bacteria that include Vibrio natriegen,Vibrio alginolyticus,Vibrio parahaemolyticus,Pseudomonas fluorescens,and Slow Edward's bacteria.And 5.95mg/ml caulis spatholobi extract and 0.12mg/ml streptomycin sulfate compound have antibacterial activity to 3 strains of gram positive bacteria that in addition to Micrococcus luteus and 9 strains of gram-negative bacteria that In addition to Morganella morganii and Pseudomonas aeruginosa.The antibacterial spectrum of the compound was more than that of the folk prescription in the case of low concentration compared to one side.MIC range of Caulis Spatholobi extract and streptomycin sulfate compound to 15 strains of bacteria is 16.70mg/ml caulis spatholobi extract + 0.39mg/ml streptomycin sulfate-30.62mg/ml caulis spatholobi extract + 0.72mg/ml streptomycin sulfate.But it is no bactericidal activity for sodium vibrio,gambogic micrococcus,mohs Morgan bacteria,pseudomonas aeruginosa and E.coli.MIC range that the remaining 10 strains of bacteria is 20.42mg/ml caulis spatholobi extract + 0.48mg/ml streptomycin sulfate-30.62mg/ml caulis spatholobi extract + 0.72mg/ml streptomycin sulfate.Intraperitoneal injection is adopted to establish the artificial tilapia streptococcus infection disease model,and based on this model respectively to investigate caulis spatholobi extract,streptomycin sulfate,caulis spatholobi extract and streptomycin sulphate compound treatment effect.The results indicate that the compound traditional Chinese medicine mixture concentration is 5.57g/kg + 0.13g/kg(Caulis spatholobi acetone extract + streptomycin sulfate),protection rate was 80.56%,and at this time 5.57g/kg caulis spatholobi extract and 0.13g/kg streptomycin sulfate protection rate were 52.63%and 13.89%,Addition and value for 66.52%,lower than the compound protective rate.Although caulis spatholobi extract has significant curative effect on tilapia streptococcus,but its dosage is too large.This paper screened the extract of Caulis Spatholobi and streptomycin sulfate compound that has synergistic antitumor activity of Streptococcus agalactiae.This compound can significantly reduce the caulis spatholobi using dose,for the development of safe and effective prevention and control of tilapia drugs do matting,streptococcus disease,for the development of new safe efficient fishery drugs provide a new way of thinking.