Contamination Characteristics Of Antibiotics And Antibiotic Resistance Genes(ARGs) In Typical Aquaculture Environments Of Three Kinds Of Crustaceans In Jiangsu Province

Antibiotics and antibiotic resistance genes(ARGs),as new pollutants,are widely distributed in aquaculture environments.In order to evaluate the contamination characteristics of antibiotics and ARGs in the crustaceans aquaculture environments in Jiangsu Province,the aquaculture environments of Eriocheir sinensis,Protocladium clacherii and Macrobrachium rosenbergii were selected as the research objects.Ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)was used to investigate the residues of 40 antibiotics(macrolides,tetracyclines,beta-lactams,quinolones,sulfonamides)in water and sediment samples of all sampling sites,and the risk quotients(RQs)approach was used to assess the risk of residual antibiotics in water;16S r RNA sequencing was used to investigate the bacterial community composition of aquaculture environments;Metagenomic sequencing was used to reveal the diversity and abundance of ARGs,the distribution of mobile genetic elements(MGEs)and the correlation between them.The results showed that there were certain antibiotic pollution and ecological risks in each sampling site,among which XY1 and XY2(two aquaculture ponds of Protocladium clacherii in Xuyi)have the lowest antibiotic pollution levels and ecological risks,while GC2(the second aquaculture pond of Eriocheir sinensis in Gaochun)and GY3(the third aquaculture pond of Macrobrachium rosenbergii in Gaoyou)have the highest.The diversity and abundance of bacteria in aquaculture environments decreased in the order of Procrustus clacherii > Macrobrachium rosenbergii > Eriocheir sinensis.Proteobacteria was the most abundant phylum in all sediments and the water of Eriocheir sinensis aquaculture environments.Cyanobacteria was the most abundant phylum in the water samples of Nanjing Procrustus clacherii and Gaoyou Macrobrachium rosenbergii aquaculture environments,while Proteobacteria and Actinobacteria were the most abundant in the water of Xuyi Procrustus clacherii aquaculture environments.Compared with Eriocheir sinensis aquaculture environments,the diversity and abundance of potential pathogenic bacteria in the aquaculture environment of Procrustonas clacherii and Macrobrachium rosenbergii were relatively higher.The main types of ARGs in the three crustaceans aquaculture environments were bacitracin,multidrug,M-L-S(macrolide-lincosamide-streptogramin)and sulfonamide,while bac A was the main subtype of ARGs.Except for GY3,the concentration of sulfonamide antibiotics was positively correlated with the relative abundance of sulfonamide ARGs at each sampling site(P <0.05).Linear regression analysis revealed that the relative abundance of ARGs in Eriocheir sinensis aquaculture environments was positively correlated with the levels of MGEs(especially for plasmids)(P <0.001),and the relative abundance of ARGs in Macrobrachium rosenbergii aquaculture environments was positively correlated with the levels of integrons(P <0.05).The results showed that compared with other aquaculture environments at home and abroad,the levels of antibiotics and ARGs pollution in three crustaceans aquaculture environments in Jiangsu Province were relatively lower,and the bacterial diversity was relatively higher.The exposure of antibiotics in aquaculture environments would inhibit the growth and reproduction of bacteria.The residues of sulfonamide antibiotics were closely related to the occurrence and transfer of sulfonamide ARGs.Horizontal gene transfer was helpful for the enrichment of ARGs in the aquaculture environments.