A Study On Population Quality Control And Application Of Specific Pathogen-free Jinding Ducks

Cultivating agricultural experimental animals of great value was an important part of enriching new resources for experimental animals.Our country was the largest duck producer in the world and the diseases were seriously endangering the aquaculture industry.Standardized non-specific pathogenic ducks was important experimental animals and raw materials for scientific researches in the agricultural field,also the production and verification of various biological products.This study was based on the cultivation of F1 Jinding ducks（A,B,C,D families）through the cultivation of research.Population breeding used duck isolator feeding,efficient filtration of air,cobalt 60 irradiation feed,drinking acidified water,strict control of the flow of people and other ways to block external environmental pollution and reinfection.At present,the population had been cultivated to the F3 generation.The total number of ducks totaled 461 and388 was female.The population was named HJD-SPF duck.In this study,three main researches on etiology,genetics and feed nutrition were conducted on the population.In terms of microbiology,the detection of pathogenic microorganisms was carried out in a regular population survey to eliminate positive individuals and ducks were purified of type duck hepatitis virus I,duck plague virus,duck circovirus,duck tembusuvirus,goose paroviruse,avian leucosis viruses,avian reovirus,avian influenza virus（H5 subtype（Re8 strain）,H7 subtype,H9 subtype）,Newcastle disease virus and avian adenovirus III were 10 kinds of pathogens.In terms of genetics,17 pairs of microsatellite markers were used to evaluate the genetic diversity of the population.The results showed that 13 sites in this population were highly polymorphic（PIC>0.5）and the average heterozygosity was 0.5816±0.0142.Twelve loci deviated significantly from Hardy-Weinberg equilibrium（P<0.01）,which was accorded with the genetic characteristics of breeding and breeding of closed colonies.In addition,SPF Jinding ducks and SPF Jinding ducks embryos were sensitive to DHV-I and DPV.To detection it is ELD₅₀ and TCID₅₀ were 10^-4.6 and 10^-4.8 in the SPF Jinding duck embryos.The umbilical cord of duck embryo was established by SPF and the stem cell line derived from the umbilical cord of duck embryo was established by tissue digestive culture method.DPV（CSC strain）was inoculated on duck embryo umbilical cord stem cells.The proliferation characteristics of DPV on stem cells derived from the umbilical cord of duck embryos were analyzed by pathological observation,PCR detection,IFA detection,and virus particle electron microscopy observation in cell sections.The results showed that the DPV（CSC strain）was first inoculated on stem cells derived from the umbilical cord of duck embryos,which caused lesions and the lesions could stably exist along with the passage of stem cells from the umbilical cord of duck embryos.The UL6 gene fragment with a size of 416 bp was amplified from F1-F35 of DPV derived from duck embryo umbilical cord-derived stem cells.Indirect immunofluorescence assays further confirmed that rabbit anti-DPV positive serum can produce specific immunofluorescence on infected cells.Electron microscopy of the cell sections revealed that intact and incompletely virus particles could be observed in the intercellular space and vesicles as well as cytoplasm.The above results indicate that DPV can proliferate on the stem cells of duck embryo umbilical cord.To sum up,we initially established a standardized SPF Jinding ducks population with no specific pathogens,with a clear genetic background and epidemic-prone diseases.Established a stem cell line derived from the umbilical cord of duck embryos that can be used for DPV proliferation.