Study On The Inhibitory Effect Of Single And Multiple Traditional Chinese Medicine On Five Pathogens And Bacterial Population Structure Of Aquaculture Rearing Water

Chinese herbal medicine is a natural medicine which contains a variety of effective ingredients.It has been widely used in agriculture,livestock industry,aquaculture and other industries partly instead of chemical drugs(such as antibiotics).However,there is no systematic evaluation regarding the synergic effects of Chinese herbal medicine on the multiple pathogens.The potential application of Chinese herbal medicine in the recirculating aquaculture system also is poorly described.This study mainly focused on compatibility of Chinese herbal medicine and their effects on five common pathogens isolated from the aquatic animals,as well as the effects of Chinese herbal medicine on microbial communities in aquaculture water and bacterial community structure change and the influence of difference analysis,aimed at rich in Chinese herbal medicine for intensive aquaculture water body micro ecological aspect research results,for traditional Chinese medicine to provide a theoretical basis for prevention and control of diseases in aquaculture production.The inhibitory effects of 25 Chinese herbal medicines,such as Prunella vulgaris,on Aeromonas hydrophila,Vibrio parahemolyticus,Bacillus cereus,Pseudomonas fluorescens and Citrobacter freundii,were determined by agar diffusion method(paper method).The minimal inhibitory(MIC)and minimum bactericidal concentration(MBC)of 4 Chinese herbs with strong inhibitory effect against 5 pathogenic bacteria were determined by double dilution method.The compatibility of Chinese herbal medicine with five pathogenic bacteria was studied by the orthogonal test.Results showed that there were 25 kinds of Chinese herbal medicines that had inhibitory effects on the 5 pathogenic bacteria,among which the P.mume,P.granatum,C.chinensis Franch,and P.chinensis had the strongest inhibitory effects.The most obvious inhibitory effect on A.hydrophila,P.fluorescens and C.freundii was on P.mume,the most obvious inhibitory effect on V.parahemolyticus was on P.mume and C.chinensis Franch,and the most obvious inhibitory effect on B.cereus was on P.mume.Orthogonal test results showed that the combination with the best bacteriostatic effect on A.hydrophila and V.parahaemolyticus was P.mume+P.granatum.The combinations with the best antibacterial effect on B.cereus were P.mume+P.chinensis and P.granatum+P.chinensis.The combination with the best antibacterial effect on P.fluorescens was P.mume+C.chinensis Franch and P.mume+P.chinensis.The combination with the best bacteriostatic effect on C.freundii was P.mume+P.chinensis and P.mume+C.chinensis Franch.In view of the five pathogenic bacteria,P.mume+P.granatum,P.mume+P.chinensis is the best antibacterial Chinese medicine compatibility combination,Chinese herbal medicine compatibility effect is better than a single drug.Meanwhile,The extract of Chinese herbal medicines such as Prunus mume and Coptis chinensis Franch greatly reduced the abundance of Vibrio sp.and other pathogens and had a great influence on the bacterial community in the aquaculture water.Illumina Hiseq high-throughput sequencing technology was used to amplify and sequence bacterial 16 SrDNA V4 region in the water in the circulating water system under the influence of Chinese herbal liquid of black plum and coptis chinensis.The OTU dilution curve gradually flattened out and the Good’s Coverage index was 99.9%,indicating that the sample sequencing depth was large enough and the number of OTU was close to the actual situation.Furthermore,OTU clustering was performed on the gene sequences,and the bacterial community composition was analyzed on the basis of OTU.The number of effective sequences obtained by HTS was 716470,and the main species were Vibrio,Cobetia,Lentisphaera and Marinobacter.In the circulating water system,the composition of the bacterial community in the water was rich,and the bacterial community structure changed with the addition of the traditional Chinese medicine extract.The dominant microorganisms in the water,vibrio(45.64%)and myxobacteria(20.88%),were successively replaced by hyacobella(30.78%).The average OTU species with the treatment of black plum was 141,while the average OTU species with coptis was 163.The results showed that the bacterial communities of A01 and E01 samples from coptis chinensis and coptis chinensis were diverse.Diversity analysis showed that there were significant differences in bacterial structure and abundance among the three groups.which laid a foundation for future studies on the application of Chinese herbal medicines on recirculating aquaculture systems.This study compared the synergic effects of Chinese herbal medicine on the multiple pathogens.the extract of P.mume and C.chinensis Franch had significant effect on aquaculture water environment and could improve the microecological water environment of seawater circulating water system to some extent.These findings provide basic data for further exploration and systematic and in-depth research in the future,and expand our understanding of the prevention and control of bacterial infectious diseases in aquaculture systems.