Fowlpox Virus Infection in a Pekin Duck (Anas platyrhynchos domesticus) Breeder Flock.

Approximately 27 million ducks are raised commercially in the US each year and Pekin ducks (Anas platyrhynchos domesticus) are the most commonly raised breed. Additionally, an increasing number of Americans are raising small flocks of poultry, which often include ducks, in their own backyards. This creates a need to better understand the imaging anatomy of ducks. However, in avian species, superimposition of organs limits evaluation of the coelomic cavity using the most common imaging modality, radiography. The use of cross-sectional imaging including computed tomography (CT) and magnetic resonance imaging (MRI) has increased in veterinary medicine research and clinical use. An anatomic atlas is essential for guiding research and diagnostic imaging. To date, no CT or MRI atlas exists for Pekin ducks. The purpose of the study is to generate a CT atlas of market-age Pekin ducks as well as CT attenuation values and measurements of coelomic organs with corresponding gross and MRI images. A total of 20 market-age, commercial Pekin ducks were imaged. Five male and five female ducks were imaged with CT; four of these ten ducks, two male and two female, were frozen and sliced in approximately 5 mm transverse sections for gross anatomic reference images. Six additional ducks, three male and three female ducks, were dissected to measure major organs. Four additional ducks were imaged using CT and MRI and necropsied for gross anatomical comparisons and landmarks. The atlas contained here may be used for future research projects and clinically to aid in diagnosis of disease in ducks.

Context Commercial ducks often experience high temperature in summer and nutritional strategies could help them cope under these conditions. Aims To assess the effects of water and feed supplements on the growth performance of Pekin ducks exposed to high ambient temperature. Methods Commercial Pekin ducks were supplemented with betaine in feed, betaine or vitamin C in water or had feed withdrawn for 9 h/day or provided with water alone, during Weeks 5 and 6 of age. Water was supplemented with an ‘in house’ electrolyte formulation and betaine in Week 6, only. The treatments were applied to two strains, the Cherry Valley (CV) and a commercial line selected from the CV strain for higher breast muscle yield identified as CVP2. On Days 29–41 of age, shed temperature was increased to 30.5°C for 9 h (08:30–17:30) and then returned to 22.7°C for the remainder of the day. Individual liveweights of ducks were measured on Day 28, Day 35 and Day 41 of age. Feed intake and water consumption were measured over Days 14–28, Days 29–35, and Days 36–41. On Day 41, one male and one female from each pen, were weighed, euthanised and the total breast muscle was removed and weighed. Key results In Week 5, all supplements supported a higher LWG, although this was limited to 4.3–6.3%, with no effects on feed intake or feed to gain ratio. In Week 6, these same supplements provided no benefit and, in fact, vitamin C had a negative effect (-4.7%) on LWG. In Week 6, the electrolyte + betaine improved LWG by 17.1%, with no effects on feed intake or feed to gain ratio. The supplements had no effects on breast muscle weight or yields. The CVP2 selected line had a substantially higher LWG, with nearly all this being due to the 15.8% higher gain seen in males, as LWG of females was similar for both strains. Conclusions Using electrolytes as a nutritional intervention can help Pekin ducks cope with adverse high temperature and should be evaluated under more extreme high-temperature challenges. Implications Water electrolyte supplementation can support Pekin duck performance under high-temperature challenge.

Enterococcus cecorum (EC) is known to cause skeletal lesions in broiler chickens and also systemic infections in Pekin ducks. Despite the importance of the pathogen, there is still a lack of serological diagnostic tools for the detection of EC infections. Here we describe the development of an in-house indirect enzyme-linked immunosorbent assay (ELISA) for the detection of EC-specific antibodies and its application by examination of 67 sera from experimentally infected Pekin ducks, 710 field samples from four Pekin duck breeder flocks previously vaccinated with inactivated vaccines, and 80 samples from commercial Pekin ducks coming from vaccinated parent flocks. All groups that had been experimentally inoculated via the air sac route were positive in the new ELISA, with significantly (P ≤ 0.05) increased mean sample/positive (S/P) ratios of 0.71–2.70 at days 7, 14 and 21 post-infection, while orally inoculated ducks and the EC-free control group remained negative with mean S/P ratios of 0.0–0.15. Antibodies were also detected in each of four vaccinated Pekin duck breeder flocks; 67.8% of the samples were antibody positive. The highest S/P ratios were found between 16 and 26 weeks (median S/P ratios from 0.15 to 1.03), but antibodies were still detected in some serum samples in weeks 61–67 post-hatch. No antibodies were detected in the commercial Pekin ducks. Antibody development in the ducks may be influenced by the composition of the inactivated vaccine. The new ELISA provides a useful tool for investigations of response to EC infections and vaccinations.

A herpesvirus (GHV 552/89) associated with high mortality in a flock of domestic geese in Australia was compared with duck virus enteritis (DVE) herpesvirus by cross-protection studies in domestic geese, Muscovy ducks and commercial Pekin ducks. In DVE-vaccinated geese, Muscovy ducks and Pekin ducks, mortality levels of 100, 50 and 0%, respectively, were recorded following challenge with GHV 552/89. Conversely, in geese, Muscovy ducks and Pekin ducks immunized with inactivated GHV 552/89, 100% mortality was observed in the geese and Muscovy ducks, and 80% in the Pekin ducks following challenge with DVE virus. The isolate was also compared with six other avian herpesviruses using cross-neutralization tests in cell cultures. No detectable cross-neutralization occurred with any of the avian herpesviruses tested. Further characterization of GHV 552/89 was undertaken by comparing its genome with strains of DVE herpesvirus using restriction endonuclease analysis of the viral DNA and a polymerase chain reaction (PCR) test. Following digestion with HindIII, the DNA fragment pattern of GHV 552/89 was found to be completely different from the DVE viruses. Similarities were found between the digestion patterns of a UK and a US DVE isolate, but both were distinguishable from a UK vaccine strain. The results of the PCR analysis and comparison using two DVE-specific primer sets did not produce specific amplification products of expected molecular weights (603 and 446 base pairs) from the GHV 552/89 genome. The PCR products derived from the DVE strains were similar to those derived from the DVE control DNA. From the results of this study, it is concluded that the goose herpesvirus GHV 552/89 is antigenically and genomically distinct from DVE herpesvirus.

Effect of water depth on pool choice and bathing behaviour in commercial Pekin ducks

Context Commercial Pekin Ducks housed in conventional open-sided sheds often experience heat stress in summer. Electrolyte or osmolyte supplements can help birds cope under heat stress. Aims To assess the effects of water electrolyte/betaine supplementation or betaine in feed on the growth performance of Pekin ducks exposed to high ambient temperature. Methods Commercial Cherry Valley Pekin ducks were fed diets with a dietary electrolyte balance (DEB) of 160 (L-DEB) or 209 (H-DEB) over Days 15–41 (D15–41) of age. Over D36–41, ducks were provided with water alone or supplemented with betaine in the feed (BF), or betaine and an ‘in-house’ electrolyte (E) formulation at 50%, 100% or 150% (D36–41) or at 100% for only 36 h on D40–41. There were 12 treatments with four replicate pens for each treatment. On D36–41 of age, temperature was increased to 28–32°C for 9 h (from 08:30 hours to 17:30 hours) and then returned to 22–24°C for the remainder of the day. Individual liveweights were taken on D28, D35, D41. During these times, feed intake and water consumption were determined. On D41, one male and one female from each pen were weighed, euthanised and breast muscle was removed and weighed. Birds were collected for commercial processing at 04:00 hours on D42. Key results Over D15–35, the DEB had no effect on bird performance. Over D36–41, for liveweight gain (LWG) there were significant interactions between treatment × week (P < 0.001) and treatment × diet (P = 0.017). Supplements E150 and E100 + 36 h supported LWG more than did other treatments, while treatments BF, E50 and E100 supported higher LWG than in controls. On the L-DEB diet, the control birds had a LWG lower than in other treatments (P < 0.05). On the H-DEB diet, the E50 supplement had highest LWG, but comparable to that in E100 + 36 h. The supplements had no effects on breast muscle yield, weight losses during transport and lairage or processed carcass weights. Conclusions The electrolyte supplements supported higher LWG during exposure to moderately adverse high temperature. Supply for 36 h supported LWG equivalent or better than did other treatments given over 6 days. The benefits could be related to increased water intake and not just electrolyte supply. Implications Water electrolyte plus betaine supplementation supports improved Pekin duck performance during a moderately high temperature challenge.

This study aimed to investigate whether the differential expression of muscle development-related genes is one of the reasons why muscle development differs between Pekin, Jianchang, and Heiwu ducks, which are all domesticated duck breeds (Anas platyrhynchos domestica) breeds. At 2 weeks of age, the RNA expression of paired box 7 (Pax7), paired box 3 (Pax3), myogenic differentiation antigen (MYOD), and myogenin (MYOG) genes were measured by quantitative polymerase chain reaction, and Pax3 and Pax7 protein levels were detected by western blot assay. Myofiber morphology was investigated using paraffin-embedded muscle sections. At 8 weeks of age, 30 ducks of each breed were slaughtered for meat quality determination. The results revealed that Pax3 and Pax7 expression levels at both the RNA and protein levels were high in the Pekin duck. In addition, MYOG expression levels in the Jianchang duck were significantly higher than in the other two duck breeds (P < 0.05). There were no significant differences in MYOD expression levels between the breeds (P > 0.05). Myofiber diameter and cross-sectional area were the largest in the Pekin duck and the smallest in the Heiwu duck. There were significant differences in slaughter data between these breeds, and muscle content was greatest in the Pekin duck. The results indicate that the muscle content of three different duck breeds is associated with the expression of satellite-cell marker genes.

A study was conducted to compare the production parameters among commercial Pekin ducks, the control population as well as meat line of Kuttanad ducks. Day-old male ducklings (n=60 each) of commercial Pekin duck, control population as well as meat line of Kuttanad duck selected for body weight over four generations were randomly allotted to five replicates of 12 birds each and were utilised for the study. The body weight, body weight gain, feed intake, feed conversion ratio, livability and carcass characteristics were calculated for the study period of eight weeks. The results showed that there was significantly (p&lt;0.05) higher body weight, body weight gain and feed intake in Pekin ducks followed by the Kuttanad meat line and control population of Kuttanad ducks. The feed conversion ratio was significantly (p&lt;0.05) better in the Pekin ducks compared to the meat line as well as the control population of Kuttanad ducks. The mortality rate had an increasing trend in accordance with the improvement in growth rate in Pekin and Kuttanad meat line. The carcass characteristics expressed in percentage of live weight did not show any significant difference among the Pekin duck, control population and meat line of the Kuttanad duck.

H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations.

Pekin and Muscovy ducks respond differently to vaccination with a H5N1 highly pathogenic avian influenza (HPAI) commercial inactivated vaccine

Canine influenza virus (CIV) of the H3N8 subtype has emerged in dog populations throughout the United States where it has become endemic in kennels and animal shelters in some regions. It has not previously been determined whether the canine-adapted H3N8 influenza virus can be transmitted to chickens, turkeys or ducks which are economically important animals that are susceptible to type A influenza virus from numerous species. Four-week-old specific pathogen-free (SPF) chickens, 3-week-old SPF turkeys and 2-week-old commercial Pekin ducks were inoculated with 10(5·2) 50% tissue culture infectious doses of CIV per bird by the intra-choanal route. The birds were observed daily, and at 2 and 4 days post-inoculation (DPI), two inoculated birds and one sham-inoculated control bird were euthanized and necropsied to evaluate gross lesions and to collect tissues for microscopic examination. Cloacal and oral swabs were collected at 2, 4 and 7 DPI to evaluate virus shed by real-time RT-PCR (rRT-PCR). Two weeks post-infection, sera were collected from all remaining birds for type A influenza antibody detection by hemagglutination inhibition assay. Clinical signs and gross lesions were not observed in any of the birds of any species nor did any seroconvert. Oral and Cloacal swab material was negative for virus by rRT-PCR. Chickens, turkeys and Pekin ducks are not susceptible to infection with CIV by simulated respiratory exposure route with the dose administered.

Characterization of Pekin duck drinking and preening behaviors and comparison when housed on raised plastic versus pine litter flooring

A conventional, inactivated oil emulsion vaccine suppresses shedding and prevents viral meat colonisation in commercial (Pekin) ducks challenged with HPAI H5N1

Experimental monochromatic light-emitting diode fixture impacts Pekin duck stress and eye development

Epidemiology of egg drop syndrome virus in ducks from South Korea