In June 2016,a disease among the cultured rock carp (Procypris rabaudi) in Yongchuan of Chongqing Municipality occurred.The aim of this study was to investigate biological characteristics and provide reference for Aeromonas veronii identification diagnosis and treatment.Pathogenic bacteria strain YY01 from the dying fishes were examined and isolated.Strain YY01's taxonomic status was identified by observing the morphology,studying the physiological and biochemical characters and sequencing the 16S rRNA and housekeeping gene gyrB.Its pathogenicity was checked by artificial infection experiment and virulence genes.Furthermore,effective medicine was detected by drug sensitivity.The 16S rRNA and gyrB gene sequence of the strain YY01 was more than 99％ homology with that of Aeromonas veronii,suggesting that the pathogen was Aeromonas veronii,which was also identified by the results of biochemical analysis.The LD50 of strain YY01 to rcok carp was 5.06 × 104 CFU/g.Four virulence genes were detected from YY01,including aerolysin (aer),hemolysin (Hly),Outer Membrane Protein Gene A (OmpA) and adhesion (Aha) genes.Antibiotic sensitivity assays showed that among 40 antibiotics tested,22 were sensitive and 11 were resistant.In conclusion,the strain YY01 is identified as Aeromonas veronii and it is proved to have strong pathogenicity.

Objective To study the existence and significance of cholesterol-intestinal hepatic circulation in rabbits by establishing a model of enterohepatic circulation and blocking enterohepatic circulation. Methods In this experiment, the experimental group and the control group were set up to conduct high-cholesterol diets and ordinary diets for differential feeding. By establishing a model of enterohepatic circulation and blocking enterohepatic circulation, cholesterol oxidase method was used to measure serum cholesterol concentration in the experimental group and the control group respectively. Based on the statistical analysis of the data for 6 months, the phenomenon of enterohepatic circulation of cholesterol was studied. Results Based on the data of 6 months, the serum cholesterol concentrations of rabbits in groups Aand Cwere gradually increased. After two months, the hypercholesterolemia was significant in the rabbits in group C. The increase degree of serum cholesterol concentration in the rabbits in group Awas weaker than that in group C. Hypercholesterolemia had no obvious effect. There was statistically significant difference between group Aand group C (P＜0. 05); serum cholesterol concentration in rabbits in group Dwas increased slightly, but the increase was not significant. The increase of serum cholesterol concentration in group Bwas more significant than that of group D. There was a statistically significant difference between group Band group D (P＜0. 05). The serum TC-time line graph was plotted with the serum cholesterol concentration in each group as the ordinate and the time as the abscissa. Compared with group A, the serum cholesterol was increased significantly in group C. Compared with group D, the serum cholesterol in group Bwas increased significantly. Conclusion This experiment shows that the cholesterol enterohepatic circulation phenomenon exists in rabbits. By blocking the enterohepatic circulation in rabbits, it has a certain effect on lowering the content of serum cholesterol in rabbits. This will provide a theoretical basis for further studying the role of blocking enterohepatic circulation in reducing cholesterol levels in the body. It provides new ideas for the clinical treatment of hypercholesterolemia by blocking the cholesterol enterohepatic circulation in clinical practice and points a direction for drug development.