Analysis Of The Pathogenicity Of Novel Goose Parvovirus To Ducklings Based On 16SrRNA And Transcriptomics Sequencing

The infection of the Novel goose parvovirus(NGPV)has caused huge economic losses to the duck industry.At present,there are few reports about its related pathogenesis.In this study,NGPV was used to infect 3-day-old ducklings to establish an animal model of short beak and dwarfism syndrome.After 2 days of infection,the ducklings appeared clustered and depressed.After 4 days of infection,it was observed that some ducklings had difficulty standing and diarrhea.After 14 days of infection,the beak length of the ducklings in the infected group was significantly lower than that of the control group(P<0.05).Infected ducklings showed symptoms of tongue protrusion,but the mental state of the ducklings gradually improved.After 21 days of infection,the weight of the ducklings in the infected group was significantly lower than that of the control group(P<0.05).The results of necropsy:After infection,the ducklings were found to have enlarged spleen and hemorrhage in the thymus.By tissue HE staining.Congestion,hemorrhage,lymphocyte necrosis,increased macrophages,and thrombosis can be observed in the thymus.Increased red pulp,congestion,and lymphopenia can be observed in the spleen.The villi can be observed to break in the intestine.The viral load of the thymus,spleen,liver,duodenum,and cecum after NGPV infection was detected by real-time fluorescent quantitative PCR.The results showed that the viral load reached a peak in each tissue after 21 days of NGPV infection.After 28 days of infection,the virus can still be detected in all tissues.There was no significant difference in the viral load of each tissue at the same time point of infection.It shows that NGPV is pantropic.Using 16SrRNA sequencing technology and gas chromatography to detect and analyze the contents of the cecum of ducklings infected with NGPV 14 d,21 d,28 d.Objective to explore the impact of NGPV infection on the cecal microbiota of ducklings.The results showed that the cecal microbial diversity was significantly reduced after 14 days of infection(P<0.05).After 28 days of infection,there was no significant difference in cecal microbiota diversity between the two groups.The test results of short chain fatty acids(SCFAs)in the contents of the cecum showed that the overall level of SCFAs in the contents of the cecum decreased after infection.After 14 days of infection,the content of acetic acid in the cecum content of ducklings was significantly reduced(P<0.05).After 28 days of infection,the content of butyric acid and propionic acid in the contents of the cecum of ducklings was significantly reduced(P<0.05).In conclusion,NGPV infection in ducklings can cause transient disturbance of cecal microbiota and decrease the content of SCFAs.The relative fluorescence quantitative PCR method was used to detect IFN and pro-inflammatory factors TNF-α,IL-6,IL-17 in the thymus and cecum.The results showed that the expression of IFN-α,IFN-β,and IFN-y reaches the peak in the early stage of infection in the thymus and cecum.The pro-inflammatory factors TNF-α,IL-6,and IL-17 also increased.It shows that NGPV can quickly stimulate the body’s immune response after infection.Transcriptomics analysis of the thymus and ileum of ducklings 14 days after infection.The results showed that a total of 109 genes changed in the ileum of the infected group.There were 78 up-regulated genes and 31 down regulated genes.A total of 189 genes in thymus of infection group were changed.There were 111 up-regulated genes and 78 down regulated genes.Differential genes in thymus are enriched in NF-κB signaling pathway,B cell receptor signaling pathway,etc.Differential genes in ileum are enriched in Toll-like receptor signaling pathway,JAK-STAT signaling pathway,Thl and Th2 cells differentiation,etc.It is speculated that NGPV may stimulate the body’s immune response through multiple pathways after infection.It is suggested that NGPV infection activates the body’s immune response and the relevant antiviral signal pathways of host cells.This study explored the possible internal connections between cecal microbial dysfunction and the formation of duckling fragile,dwarfism,and short beaks after NGPV infection.And the relevant signal pathways that activate the host immune response by NGPV infection.The above test results are expected to provide a theoretical basis for the study of the pathogenic mechanism of NGPV.