Research

Publications
Title: Pathogen Isolation and Identification of The Zebrafish?Hole in The Head?Disease and Diagnosis of Common Diseases
First author: Liu Li-Yue; Pan Lu-Yuan; Sun Yong-Hua
Journal: PROGRESS IN BIOCHEMISTRY AND BIOPHYSICS
Years: 2022
Volume / issue: /
DOI: 10.16476/j.pibb.2022.0146
Abstract: Objective Zebrafish is one of the most widely used model animals for scientific research in theworld.The health and quality of zebrafish are the basis for accurate data and reliable results.With the rapiddevelopment of zebrafish related research in China,the number of fish diseases in research facilities has been increasing in recent years.However,the research and analysis on these diseases have been lacking.A novel lethaldisease,hole in the headdisease has spread in several zebrafish facilities since2018,whose pathogen wasunrecognized and hard to be controlled.Pathogen identification is urgently needed,and the analysis and advice ofhealth administration are required for the fast-growing field. Methods We necropsied the brain tissue from thehole in the headdisease zebrafish.After the brain tissue was homogenized,the pathogen was isolated and cultured on brain heart infusion agar(BHIA)plates. The isolated pathogen was analyzed for biochemicalcharacteristics and16S rDNA homology.The Koch's Postulate was fulfilled to confirm the pathogen.In addition,we analyzed the zebrafish disease data collected by China Zebrafish Resource Center(CZRC)from2017to2021and summarized the characteristics of various common diseases.ResultsThe isolated and identified pathogenof thehole in the headdisease has the same physicochemical properties withEdwardsiella ictaluri,which alsofulfilled the Koch's Postulate.The16s DNA sequence of this pathogen was highly homologous toEdwardsiellaictalurid.From2017to2021CZRC has collected121disease and fish death cases in Chinese zebrafish facilities.We found that50.4% fish health problems were directly or indirectly caused by equipment failure and abioticfactors,including12.39% fish death caused only by improper equipment maintenance and water qualityproblems.The most lethal problem was gas poisoning.Among all the known pathogens,bacterial pathogens werethe most common,accounting for83.46%,fungal pathogens accounted for2.47%,and parasitic pathogensaccounted for1.65%.Among all the known bacterial diseases,the opportunistic pathogens of the genusAeromonaswere the most common,followed byEdwardsiella,accounting for34.65% and23.76% respectively.ConclusionEdwardsiella ictaluriwas isolated and identified as the pathogen ofhole in the headdisease.Thehighest incidence of zebrafish disease is bacterial infection,and nearly half of zebrafish health problems arecaused by abiotic factors.Well-maintained equipment and proper water quality are the most importantprerequisites to ensure the health of zebrafish,managements of daily hygiene are the main means to prevent fishdiseases,and the prevention of bacterial diseases is the top priority of zebrafish farming