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A comparison of the responses of dispersed steroidogenic cells derived from embryonic adrenal tissue from the domestic chicken (Gallus domesticus), the domestic Pekin duck and the wild mallard duck (Anas platyrhynchos), and the domestic muscovy duck (Cairina moschata).

The steroidogenic responsiveness of adrenal cell suspensions prepared from domestic chicken adrenal tissue at the end of embryogenesis was compared to the responses of similar preparations derived from the wild and domesticated mallard duck (Anas platyrhynchos), and the domesticated muscovy duck (Cairina moschata). In all cases, the masses of corticosterone (B), aldosterone (Aldo), and deoxycorticosterone (DOC) released from cells incubated in medium containing 1-24 ACTH exceeded the estimated hormone content of the freshly dispersed cells; the induced rates of corticosteroid release were, therefore, presumed to reflect de novo hormone synthesis. When chicken cells were incubated in medium containing 1-24 ACTH, there were progressive, dose-dependent increases in B and DOC synthesis over a range of concentrations spanning two orders of magnitude; only small, non-dose-related, albeit significant, increases in Aldo release were observed. The 1-24 ACTH-induced increases in B and Aldo synthesis by the mallard and Pekin duck cells exposed to the same range of concentrations were up to 40 and 60 times greater than the corresponding responses of the chicken cells. The rates of 1-24 ACTH-induced B and DOC release from muscovy duck cells were similar to those from the Pekin duck cells; compared with the mallard duck cells, however, the muscovy duck cells were less sensitive and the maximum inducible rate of B release was significantly lower. The pattern of 1-24 ACTH-induced Aldo release from the muscovy duck cells was indistinguishable from that of the mallard duck cells, although the maximum inducible increase occurred at a lower concentration. Angiotensin II (AII) induced very small, but significant increased in B, Aldo, and DOC release from the chicken cells but in a nondose-related fashion. In contrast, mallard, Pekin, and muscovy duck cells all responded in a dose-dependent manner when incubated in medium containing AII. In each instance the maximum rate of Aldo synthesis induced by AII was about one-tenth of the corresponding rate induced by 1-24 ACTH. The maximum rates of B synthesis induced by AII, however, were extremely low compared with the rates induced by 1-24 ACTH. Thus, when maximally stimulated with AII the B:Aldo output ratio ranged from 1.0 to 1.9, whereas the corresponding ratio was between 9.0 and 17.0 when the cells were maximally stimulated with 1-24 ACTH.

Adrenal Cortex Hormones

[Ultrastructure of the granulosa cells of the ovarian follicle of ducks (Barbary duck: Cairina moschata, Pekin duck: Anas platyrhynchos].

In the granulosa cells of the ovarian follicle of the ducks, the Golgi apparatus is developed, the granular endoplasmic reticulum is important. Owing to these characters, these cells are probably oriented towards the elaboration of proteins. The seasonal variations of the aspect of these cells are important: in January all organits are not very developed when in May they are all very developed. For a determined season all cells present the same aspect.

Animals

Duck hepatitis B virus infection and duck hepatocellular carcinoma.

To study the relationship between duck hepatitis B virus (DHBV) infection and duck hepatocellular carcinoma (DHCC), histological examination and DHBV DNA hybridization were performed in 875 ducks from three flocks in Qidong County. Among them, 34 suffered from hepatoma, including 23 hepatocellular carcinoma, 8 cholangiocarcinoma and 3 hepatocellular-cholangiocarcinoma. Of the 34 ducks with hepatoma 27 were positive for DHBV DNA in the liver and/or serum. DHBV DNA was demonstrated in neoplastic nodules of 22 ducks. Southern blot analysis showed that 13 cases were of the integrated pattern of DHBV DNA in neoplastic nodules. The paratumor tissues of 14 ducks with massive tumor were analysed at the same time. Five cases showed integrated pattern, 4 cases free pattern and the other 4 cases both integration and free pattern of DHBV DNA. The hybridization pattern of DHBV DNA in tumor nodule was different from that in paratumor regions in 11 cases and identical in 3 cases. DHBV antigen was positive in 13 tumor nodules and 21 paratumor tissues in the 34 ducks with hepatic tumor by both victoria blue and orcein stain methods. Advanced liver diseases were found in 30 out of the 34 ducks with hepatoma, including 12 cirrhosis and 18 chronic active hepatitis. In southern blot analysis of 122 DHBV DNA positive Qidong ducks without hepatoma, only free pattern of DHBV was seen, while 44 control ducks from Changchun were negative for DHBV DNA. Neither hepatic tumor nor liver diseases were seen in the control ducks. The results suggest that hepatocellular carcinoma in ducks is similar to that in human HCC. They have a high frequency of viral DNA integrated into the host genome and a liver disease background.

Animals

Hepatic neoplasms in aflatoxin B1-treated, congenital duck hepatitis B virus-infected, and virus-free pekin ducks.

To assess the effects of the combination of persistent hepadnavirus infection and chemical carcinogen exposure, aflatoxin B1 (AFB) was administered p.o. for 60 days to congenitally duck hepatitis B virus (DHBV)-infected and virus-free Pekin ducks, starting at 3 days of age, during a 28-month study. Hepatic neoplasia occurred only in AFB-dosed ducks. Hepatocellular carcinomas or biliary carcinomas occurred in 4 of 8 DHBV-infected and 3 of 4 DHBV-free ducks, and hepatocellular adenomas developed in 2 DHBV-infected AFB-dosed ducks that survived 20 months or longer. Altered foci of hepatocytes similar to those observed in chemical carcinogen-dosed rodents, characterized by enlarged eosinophilic hepatocytes or vacuolated cytoplasm, occurred in AFB-dosed ducks. Cells in foci or hepatic neoplasms did not contain histochemically detectable gamma-glutamyltranspeptidase but were distinguished from uninvolved parenchyma by altered glycogen content. Immunohistochemical staining indicated that DHBV core antigen persisted in liver, spleen, pancreas, and, to a lesser extent, kidney of most congenitally infected ducks up to 28 months of age. Hepatic neoplasms contained only patches of hepatocytes were detectable viral antigen. Southern blot analysis of restriction endonuclease-digested neoplastic and normal liver DNA revealed high molecular weight forms of DHBV DNA consistent with integration of viral DNA into the genome of hepatic neoplasms from 3 of 4 DHBV-infected ducks but not nontumorous liver. These findings indicate that AFB is a potent hepatic carcinogen in ducks and that persistent congenital DHBV infection did not contribute significantly to the emergence of hepatic neoplasia in ducks under these conditions.

Aflatoxin B1

Duck plague virus replication in muscovy duck fibroblast cells.

Duck embryo fibroblast cell cultures from seven species of ducks were compared for virus yield, plaque quality, and sensitivity to infection by the duck plague herpesvirus (duck virus enteritis). Muscovy duck and wood duck cells gave the best results for virus yield and plaque quality, but muscovies were considered superior because they are more available than wood ducks. Pintails and lesser scaup gave the poorest results, and pekin duck, black duck, and redhead duck were intermediate. A growth curve for the virus, determined in muscovy cells, had a latent period of six hours and a maximum new virus titer reached at 36 hours. Because of their superior plaque production and ability to replicate the virus, muscovy embryo fibroblasts (MCE) are recommended for diagnostic and research work.

Animals

The sequential change of serum 2',5' oligoadenylate synthetase in different infectious patterns of duck hepatitis B virus in ducks in experimental transmission.

Duck hepatitis B virus (DHBV) shows clear age-dependent infectious patterns like that of Hepatitis B virus, and many factors have been assumed to have a role in the persistence of the infection. In the present study, the activities of the interferon-induced enzyme 2',5' oligoadenylate synthetase (2,5AS) were observed sequentially in the serum of ducks experimentally infected with DHBV on posthatch days 1, 7 and 14. These were compared with the infectious pattern to investigate whether the endogenous interferon response after infection in ducks of different ages has a major role in its determination. The infectious pattern of DHBV in 1-day-old ducks was persistent without hepatitis and the others were transient with hepatitis. Persistently infected ducks showed significantly lower activities of 2,5AS compared with those with transient hepatitis, which resulted in a rapid elimination of DHBV. Although 1-day-old ducks showed significantly high 2,5AS compared with non-infected ducks, interferon response alone appeared to be insufficient for the elimination of DHBV. The immune response seemed necessary for the complete elimination of DHBV by way of evoking hepatitis and stimulating more interferon response during the usual infectious course. The interferon system alone did not seem to have a critical role in determining the infectious pattern. Other factors, including the immune response to the virus, seemed to have a major role in this problem.

2',5'-Oligoadenylate Synthetase

[Duck hepatitis B virus (DHBV) and viral DNA in duck hepatocellular carcinoma and liver tissue].

The hybridization test for duck hepatitis B virus DNA was performed in 34 ducks with hepatoma from Qidong, Jiangsu province. Among the 34 hepatoma ducks, 18 were positive for DHBV DNA in the serum and 27 were positive in the tumor and/or liver tissue. Tissue sections were stained with Victoria blue nuclear fast red for detecting DHBV surface antigen. Victoria blue positive cells were found in 11 tumors and 15 paratumorous regions of 23 ducks with hepatocellular carcinoma. Although paratumorous regions were positively stained in 3 of 8 ducks with cholangiocarcinoma, all were negative within their tumors. All paratumorous regions and 2 tumor regions of 3 ducks with hepatocellular-cholangiocarcinoma were positive for Victoria blue. The results suggest that duck hepatocellular carcinoma be closely related to DHBV infection.

Animals

An outbreak of duck virus enteritis (duck plague) in Alberta.

Duck plague (Duck virus enteritis) was disgnosed in a resident population of Muscovy ducks (Cairina moschata) on a small game farm in Alberta. This disease has not been reported previously in Canada. Clinical signs consisted of cyanosis, depression and acute death. Necropsy of two Muscovy ducks revealed lesions typical of the disease. There were ulcerations with pseudomembranes in the small intestine, ulcerations with caseous plaques in the esophagus and eosinophilic intranuclear inclusion bodies in the spleen. Clinical disease with mortality was reproduced in young ducklings injected with tissue homogenates from field cases. All surviving inoculated ducklings seroconverted to highly significant titres of neutralizing antibodies to duck virus enteritis (DVE) virus. All attempts to isolate the agent in embryonating duck eggs or primary tissues cultures of duck and chicken kidney were negative. Identification of the DVE virus was accomplished by serum neutralization with ducklings as the host system.

Alberta

Natural and experimental infection of wild mallard ducks with duck hepatitis B virus.

Wild duck populations were investigated over a 4 year period for duck hepatitis B virus (DHBV) infection and liver disease. It appeared that DHBV is endemic in wild migratory mallards from France and the U.S.A., although neither hepatocellular carcinoma nor viral DNA integration could be detected in liver samples examined. The follow up of natural infection indicated that wild mallards developed significantly higher serum titres to DHBV DNA than Pekin ducks. The results of experimental transmission demonstrated that such differences in viraemia were not related to the breed of ducks but to the virus isolate, since the wild mallard-isolated DHBV (DHBV WM) induced significantly higher viraemia in both mallard and Pekin ducklings compared to the domestic Pekin DHBV (DHBVP) isolate. The naturally infected mallard and Pekin ducks had only minor histological lesions of the liver compared with experimentally infected birds. There was no correlation between the intensity of viraemia and the severity of liver lesions, suggesting that as for mammalian hepadnaviruses the hepatic injury in DHBV-infected ducks is probably immunologically mediated.

Animals

[Duck hepatitis B virus DNA in multiple primary cancers and metastatic tumors in duck liver].

Duck hepatitis B virus (DHBV) DNA was detected in both multiple primary cancers and intrahepatic metastatic tumors in duck liver by Southern blot technique. Among 7 ducks with multiple primary tumors in the liver, the banding pattern of integrated DHBV DNA in different tumors was identical in 3 animals but different in 2. One duck showed a similar hybridization pattern in different tumor nodules and the remaining one was negative for DHBV DNA. Integrated DHBV DNA was also identified in one duck with metastatic tumor in the lung, in which the hybridization pattern was the same as that of the primary hepatocellular carcinoma. The presence of the same distinct hybridization bands in various tumor nodules indicated that they may arise from the same clone of neoplastically transformed cell. Different hybridization bands showed that tumors may arise from different clones. The results suggest that hybridization pattern of hepatic carcinoma with viral DNA probe could be used as a clone marker of transformed cells to distinguish multiple primary hepatic cancers from intrahepatic metastasis.

Adenoma, Bile Duct

In vitro incorporation of 1-14C acetate by blood cells of normal ducks and ducks infected with Plasmodium lophurae.

Several investigations have been made, on a qualitative basis, of in vitro incorporation of 1-14C acetate into the lipids of whole blood from normal ducks and ducks infected with Plasmodium lophurae (1,3,4). It was found generally that the percent labeling in blood cells and plasma was higher for infected ducks than for normal ducks. The present study was concerned with quantitative determination of the incorporation of 1-14 C acetate into the lipids of purified erythrocytes (RBC) and leukocytes (WBC) of normal and infected ducks.

Acetates

Occurrence of duck virus enteritis (duck plague) in Pennsylvania, 1968-74.

During the 7-year period 1968-74 cases of duck virus enteritis (duck plague) were diagnosed in waterfowl in Pennsylvania. Muscovy ducks were affected in 8 cases, geese in 3 cases, and mallard ducks in 1 case. In 5 of these cases either domestic or wild ducks were closely associated with infected waterfowl but were unaffected.

Animals

[Attempt to cause hepatitis in duck hepatitis B virus carrier ducks by immunization with DHBV protein].

In order to investigate the hypothesis that viral hepatitis is a host immune response against viral protein presented on hepatocytes, we attempted to cause hepatitis in DHBV carrier ducks by immunization with DHBV protein. While ducks injected with Freund Complete Adjuvant (FCA) showed only weak hepatitis, those immunized with DHBV particle protein showed severe hepatitis. This same procedure could not cause significant inflammation in the liver of ducks without DHBV infection. The severity of hepatitis was well associated with the frequency of the immunization. However, the degree of hepatitis activity was different among same times immunized ducks. Occurrence of hepatitis assumed to have close association with host immune response against viral protein.

Animals

[Ultrastructural study of duck hepatitis B virus in biliary epithelial cells of duck liver].

Liver specimens from Shanghai Ma ducks infected with duck hepatitis B virus (DHBV) were examined by immunohistochemical technique and electron microscopy. The results showed that DHBV and DHBV antigen were found not only in the hepatocytes but also in the biliary epithelial cells of infected ducks. Electron microscopy also revealed that incomplete spherical particles, 40-50 nm in diameter, were present in the dilated cisternae of rough endoplasmic reticulum (RER), and complete spherical virions, 55-65 nm in diameter, existed in the cytoplasmic vesicles and cytoplasm in small amounts. The results of the present study seem to confirm the possibility of infection and replication of DHBV not only in the liver cells but also in the biliary epithelial cells of ducks.

Animals

Mortality from duck plague virus in immunosuppressed adult mallard ducks.

Environmental contaminants contain chemicals that, if ingested, could affect the immunological status of wild birds, and in particular, their resistance to infectious disease. Immunosuppression caused by environmental contaminants, could have a major impact on waterfowl populations, resulting in increased susceptibility to contagious disease agents. Duck plague virus has caused repeated outbreaks in waterfowl resulting in mortality. In this study, several doses of cyclophosphamide (CY), a known immunosuppressant, were administered to adult mallards (Anas platyrhynchos) to determine if a resultant decrease in resistance to a normally sub-lethal strain of duck plague virus would occur, and induce mortality in these birds. Death occurred in birds given CY only, and in birds given virus and CY, but not in those given virus only. There was significantly greater mortality and more rapid deaths in the duck plague virus-infected groups than in groups receiving only the immunosuppressant. A positively correlated dose-response effect was observed with CY mortalities, irrespective of virus exposure. A fuel oil and a crude oil, common environmental contaminants with immunosuppressive capabilities, were tested to determine if they could produce an effect similar to that of CY. Following 28 days of oral oil administration, the birds were challenged with a sub-lethal dose of duck plague virus. No alteration in resistance to the virus (as measured by mortality) was observed, except in the positive CY control group.

Animals

Epitope-specific antibody response to the surface antigen of duck hepatitis B virus in infected ducks.

In order to investigate the immune response to duck hepatitis B virus (DHBV) infection, newly hatched DHBV DNA negative ducklings were injected with infectious serum of sufficiently low DHBV-DNA titer to allow clearance of viremia. Of 20 injected ducklings, 13 (65%) became viremic. Of these, 6 (46%) cleared virus from the serum 3 to 22 weeks postinjection. The convalescent sera of these 6 animals were tested for an epitope-specific antibody response in a highly specific competitive inhibition assay using a panel of monoclonal antibodies against duck hepatitis B surface antigen (DHBsAg) that had been well-characterized. All 6 animals recovering from DHBV infection developed antibodies to epitopes on the preS and S proteins of DHBV. Antibody responses were highly variable with marked differences between animals in the extent and specificity of the antibody response. The humoral response to DHBsAg was prolonged in some animals but transient in others. No antibody to preS or S was detected in either preimmune sera or sera of control animals from an uninfected flock. Infected animals that did not clear viremia also remained antibody negative. The humoral responses to neutralizing preS epitopes III and V were weak but antibodies to two immunodominant epitopes on the preS region (II and B) were present in all 6 animals. The humoral response to the two epitopes in the S region was transient and of lower titer when compared to the two immunodominant preS epitopes. The two immunodominant preS epitopes may play an important role in clearance of DHBV infection in ducks.

Animals

Ultrastructural study on extrahepatic infection of duck hepatitis B virus in ducks.

Kidney and pancreas tissues from congenitally infected Ma ducks with duck hepatitis B virus (DHBV) were examined by immunohistochemical staining technique and electron microscopy. The immunostaining showed that DHBV antigen was localized in the cytoplasm of tubular epithelial cells of kidney and acinar cells of pancreas of infected ducks. Under electron microscope, we found that complete and incomplete DHBV particles existed in the dilated cisternae of rough endoplasmic reticulum of both the cells. The size of complete and incomplete virus particles was nearly uniform in both the cells, 50-65 nm and 40-50 nm in diameter respectively. Therefore, extrahepatic infection and replication of DHBV were directly demonstrated ultrastructurally.

Animals