Studys On Eggshell Change And CaBP-D28k Gene Expression In Oviduct After AIV H9N2Infected With Layers

H9N2, a subtype of avian influenza virus, is distributed throughout the world. H9N2canexert negative influence on the production and the quality of eggs after infecting layers,especially during the peak time. When infected H9N2avian influenza virus, the eggproduction quickly decrease, and their eggshell will turn sandy, soft and deformed, whichcauses great loss to poultry industry. The eggshell quality becomes worse and easy to eggshellcrack, pose a threat in bacterial infection because of crack, which cause food safety andpotential economic loss. At present, what remains to know is the changing rules for thequality of eggshells after layers get infected with subtype H9N2of avian influenza virus. Theformation area of eggshell is mainly in the uterine of layers oviduct, when the egg through thefallopian tubes and uterus isthmus, the various components of the eggshell assembles eggshell.Calcium binding protein related CaBP-D28k gene is related to the quality of eggshells.In present study, subtype H9N2of avian influenza virus was used for artificial linfecting30-week old non-immuned healthy layers at their peak period of production, and eggs werecollected on the first, second, third and fifth day after the infection, in addition, layers oviductwere also collected understerility when eggs were in uterus. The collected eggs were broken,and a certain amount of eggshell was used to determine the content of calcium in the shellusing atomic spectrophotometry, and the ultrastructure of inner and outer surfaces as well astransverse surface of eggshell was observed using scanning electron microscope. The totalRNA of infundibulum、magnm、isthmus、uterus and vagina five different parts of the oviductwere extracted using Trizol, then reverse-transcribed into cDNA. The expression level ofcalcium-binding protein D28K (CaBP-D28k) gene in different parts of the oviduct wereanalyzed using the relative fluorescence quantitative method, so that we can further study therelationship between the eggshell calcification and the eggshell qualit.The results are asfollows:The expression of CaBP-D28K gene decreased gradually and regularly in the uterustissue of the layers’ oviduct, with the content of Ca in eggshells reducing by degrees. Withscanning electron microscope for ultra microstructure observation, it was discovered that theouter surface of eggshells gradually became rough, the cross-section turning thinner, and thestructure going looser; and there was a loosened fibre structure on the inner surface of eggshells.On the seventh day of infection, the expression of CaBP-D28k began to recover and riseup diminutively, meanwhile, the content of Ca in eggshells increased at a slow speed, withcross-section becoming thicker and no obvious change of fibre structures on the inner surface.The result showed that there was a positive correlation between the quality change ofeggshells and the gene expression of CaBP-D28k after the layers got infected with subtypeH9N2of avian influenza virus.