Project description:Recently, infectious disease outbreaks characterized by swelling and hemorrhagic liver and kidneys occurred in Muscovy ducklings in China. Four viruses were isolated and identified as adenoviruses by transmission electron microscopy (TEM) and polymerase chain reaction (PCR). Sequence analysis identified the new isolates as duck adenovirus 3 (DAdV-3), species Duck aviadenovirus B. The pathogenicity of the new isolate DAdV-3 FJGT01 was investigated using challenge experiments. The gross lesions in the animal experiment were similar to the clinical lesions observed in the diseased ducks. TEM examination of liver sample showed that virions accumulated and arranged in crystal lattice formations in the nuclei of hepatocytes. The present study provides new information about the epidemiology and characteristics of duck adenovirus associated with Muscovy ducklings.
Project description:Duck Tembusu virus disease, caused by the duck Tembusu virus (DTMUV), can lead to a severe reduction in egg production and growth retardation in laying ducks and ducklings, respectively. In this study, we engineered a novel recombinant adenovirus expressing the E protein of DTMUV (rAd-E) in AAV-293 cells (analyzed by western blot and indirect immunofluorescence assays). Intramuscular immunization of Cherry Valley ducks with rAd-E was performed to evaluate host cellular and humoral immune responses. Compared to the phosphate-buffered saline administered group and the negative control wild-type adenovirus (wtAd) group, the rAd-E vaccinated group showed increased cellular and humoral responses. The results from the cytokine release and lymphocyte proliferation assays showed that rAd-E induced a stronger cellular immune response than the control group (P<0.01), 4 weeks after primary immunization. The results of enzyme-linked immunosorbent and virus neutralization assays showed that rAd-E induced higher titers of specific neutralizing antibodies, 2 weeks after primary immunization. The DTMUV challenge experiment showed a higher survival rate (80%) of ducks in the rAd-E group, when challenged with 0.5 ml (ELD50=10-2.67/0.2 ml) of the DTMUV strain AH-F10. These results indicate that rAd-E effectively protects ducks against DTMUV infection. Therefore, rAd-E could be a vaccine candidate to provide an effective and safe method for prevention and control of DTMUV infection.
Project description:Globally, the production of Pekin ducks for meat and eggs is considerable, with an estimated >200 million ducks slaughtered yearly for their meat in the United States and the European Union alone. However, despite the size of the Pekin duck industries, there is a lack of research-based guidance regarding the welfare of the ducks. The purpose of this systematic review is to examine and summarize available scientific literature related to the welfare of Pekin ducks raised on commercial farms for meat and eggs. Specifically, we aimed to identify topics where sufficient literature exists to support best-practice duck welfare recommendations, as well as further research needs. The literature search targeted original research papers and review articles published in English. Six pre-establish inclusion/exclusion criteria were applied, yielding 63 publications. We summarized their content based their main topic of focus. For all original studies, we additionally recorded the country where the study was executed, scale of the project (commercial or experimental barns), general information about the housing system and management (waterers, flooring, ventilation, group size, and space allowance), and the types of outcome variables collected. We begin with an overview of key publication trends. We then synthesize and discuss welfare outcomes related to key housing/management decisions: bathing water, flooring and litter, stocking density and space availability, ventilation/air quality, lighting, outdoor access, and for egg laying birds the availability of nest boxes. Throughout, we outline specific research gaps, as well as overarching research needs.
Project description:Duck Tembusu virus (DTMUV) and duck plague virus (DPV) are typical DNA and RNA viruses of waterfowl, causing drastic economic losses to the duck farm industry in terms of high mortality and decreased egg production. These 2 viruses reappear from time to time because the available vaccines fail to provide complete immunity and no clinical antiviral drugs are available for them. In the present study, we evaluated the antiviral activity of SC75741 for DTMUV, DPV, and the model virus, vesicular stomatitis virus infection in duck cells. SC75741, a nuclear factor-kappa B (NF-κB)-specific inhibitor in mammal cells, revealed the highest antiviral activity among the inhibitors specific to c-Jun NH<sub>2</sub>-terminal kinase, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase (p38), and NF-κB signaling. The antiviral activity of SC75741 was dose-dependent and showed effects in different duck cell types. Time-addition and duration assay demonstrated that SC75741 inhibited virus infection in the middle of and after virus infection at least for 72 h in duck embro fibroblast cells. The DPV viral adsorption and genomic copy number were reduced, indicating that SC75741 blocks the phase of the virus life cycle at viral entry and genomic replication. In addition, SC75741 enhanced the expression of interferon only when stimulator of interferon genes (STING) was overexpressed or pre-activated by the virus infection, suggesting that SC75741 acts as a STING agonist. In conclusion, SC75741 is a candidate antiviral agent for DTMUV and DPV.
Project description:Duck viral hepatitis (DVH) is an acute, highly lethal infectious disease of ducklings that causes huge losses in the duck industry. Duck hepatitis A virus genotype 3 (DHAV-3) has been one of the most prevalent DVH pathogen in the Asian duck industry in recent years. Here, we investigated the genetic basis of the resistance and susceptibility of ducks to DVH by comparing the genomes and transcriptomes of a resistant Pekin duck flock (Z8) and a susceptible Pekin duck flock (SZ7). Our comparative genomic and transcriptomic analyses suggested that NOD1 showed a strong signal of association with DVH susceptibility in ducks. Then, we found that NOD1 showed a significant expression difference between the livers of susceptible and resistant individuals after infection with DHAV-3, with higher expression in the SZ7 flock. Furthermore, suppression and overexpression experiments showed that the number of DHAV-3 genomic copies in primary duck hepatocytes was influenced by the expression level of NOD1. In addition, in situ RNAscope analysis showed that the localization of NOD1 and DHAV-3 in liver cells was consistent. Altogether, our data suggested that NOD1 was likely associated with DHAV-3 susceptibility in ducks, which provides a target for future investigations of the pathogenesis of DVH.
Project description:The reads of duck transcripome was mapped to the duck genome and help to identify the UTR regions of predicted genes. The expression level difference between the tissue spleen and liver will help us to detect the immune-related and fatty acid metabolism related genes. Duck transcriptome was sequenced to improve the gene annotation quality, and to detect the differently expressed genes in liver and spleen tissues.
Project description:Tripartite motif-containing 32 (TRIM32) is an E3 ubiquitin ligase with multiple functions. In this study, we amplified TRIM32 gene from the Cherry Valley duck, and its cDNA sequence contained an open reading frame of 1,950 bp that encodes 649 amino acids. Duck TRIM32 (duTRIM32) mRNA was expressed in all tissues tested. A series of immune-related genes that were induced by viral infection, including interferon alfa, IL-1β, retinoic acid-inducible gene-I, Mx, and OAS, were regulated by duTRIM32 expression. DuTRIM32 overexpression inhibits duck Tembusu virus (DTMUV) replication in the early stages of viral infection. Knockdown of duTRIM32 expression by siRNA reduced the ability of duck embryo fibroblast cells to mount a type Ⅰ interferon response to DTMUV. Therefore, our results suggest that the duTRIM32-mediated signal pathway plays an essential role in DTMUV infection-induced innate immune response.
Project description:This study aimed to isolate, culture, and characterize duck primordial germ cells (PGCs) and to compare these cells with chicken PGCs. We first cultured Muscovy duck (Cairina moschata) circulating PGCs and gonadal PGCs (gPGCs) in the modified serum-containing medium used to amplify chicken PGCs. gPGCs were found to proliferate better in serum-free chemically defined medium than in serum-containing medium. Thereafter, gPGCs were similarly isolated from 2 other duck breeds, the Pekin duck (Anas platyrhynchos) and the hybrid mule duck (C. moschata × A. platyrhynchos), and amplified for a limited period of time in the chemically defined culture condition, but sufficiently to be characterized and transplanted. Cultured gPGCs of all 3 duck breeds were characterized by Periodic acid-Schiff staining, immunocytochemical staining, and expression analysis of germline-specific and pluripotency genes. Cultured duck gPGCs colonized the gonads after being genetically labeled and injected into recipient embryos. Taken together, these results demonstrate that duck PGCs retain their germline characteristics after being isolated, expanded in vitro, and genetically modified. Further studies are required to establish the optimal conditions for long-term culture of duck PGCs, which may involve supplementing the culture medium with other growth factors or compounds.
Project description:A genetic linkage map for the duck (Anas platyrhynchos) was developed within a cross between two extreme Peking duck lines by linkage analysis of 155 polymorphic microsatellite markers, including 84 novel markers reported in this study. A total of 115 microsatellite markers were placed into 19 linkage groups. The sex-averaged map spans 1353.3 cM, with an average interval distance of 15.04 cM. The male map covers 1415 cM, whereas the female map covers only 1387.6 cM. All of the flanking sequences of the 155 polymorphic loci--44 monomorphic loci and a further 41 reported microsatellite loci for duck--were blasted against the chicken genomic sequence, and corresponding orthologs were found for 49. To integrate the genetic and cytogenetic map of the duck genome, 28 BAC clones were screened from a chicken BAC library using the specific PCR primers and localized to duck chromosomes by FISH, respectively. Of 28 BAC clones, 24 were detected definitely on duck chromosomes. Thus, 11 of 19 linkage groups were localized to 10 duck chromosomes. This genetic and cytogenetic map will be helpful for the mapping QTL in duck for breeding applications and for conducting genomic comparisons between chicken and duck.