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1. The objective of this study was to determine the effects of two mixed LED light spectra on duck production, stress and fear responses. Pekin ducks were reared under either white/red (WR) or white/blue (WB) LED light.2. No differences were observed in feed conversion ratio (P = 0.690) or d 35 body weight (P = 0.919). Furthermore, no differences were observed in plasma interleukin-12 concentrations (P = 0.449), anti-keyhole limpet haemocyanin IgG titre (P = 0.503) or composite physical asymmetry score (P = 0.839). WR caused lower heterophil to lymphocyte ratios (0.40 ± 0.03, P = 0.029) and plasma corticosterone concentrations (4498 ± 534 pg/ml, P = 0.038) than WB (0.58 ± 0.08; 6518 ± 795 pg/ml, respectively). No differences were found in the number of attempts to induce tonic immobility (TI) or in inversion intensity. A shorter latency to first head movement during TI (9.44 ± 1.22 s, P = 0.06) and an overall shorter latency to right from TI (25.66 ± 2.99 s, P 0.001) was observed for birds under WR compared to WB (20.91 ± 6.01 s; 58.76 ± 8.86 s). The duration of time spent in the second stage of TI, where birds observed their environment using head movements while still remaining immobile on their backs, was shorter in WR (16.23 ± 1.73 s, P = 0.001) compared to WB (37.85 ± 6.38 s).3. The results indicated that rearing ducks under WR caused less stress susceptibility and fear responses compared to ducks under WB. Pekin duck welfare may be compromised by blue LED light exposure, even at supplemental levels utilised in commercial poultry lighting.

A 2 &times, 6 factorial experiment was conducted to determine the influences of dietary metabolizable energy (ME) and methionine (Met) levels on growth performance, carcass traits, and plasma biochemical parameters of starter Pekin ducks from 1 to 21 days of age. A total of 600 one-day-old male Pekin ducklings were randomly assigned to 12 groups (six replicates each group and eight ducks per replicate) in a 2 &times, 6 two-factor arrangement. The basal Met levels of two basal diets (11.54 and 12.52 MJ/kg ME) were 0.31 and 0.29%, respectively. The crystalline L-Met was supplemented to yield six diets according to different supplemental levels (0, 0.05, 0.10, 0.15, 0.20, and 0.25%). The results showed that the body weight (BW) and average daily weight gain (ADG) were increased (p &lt, 0.05) with increasing dietary Met levels. Dietary ME levels changed from 11.54 to 12.52 MJ/kg increased the BW and ADG (p &lt, 0.05) as well as decreased the average daily feed intake and feed to gain ratio (p &lt, 0.05). As the dietary Met level increased, leg muscle yield increased (p &lt, 0.05). Conversely, increasing the dietary ME level decreased the leg muscle yield (p = 0.0024) and increased abdominal fat (p &lt, 0.001). Meanwhile, the concentrations of total cholesterol (TCHO), high-density lipoprotein cholesterol (HDLC), and low-density lipoprotein cholesterol (LDLC) in plasma were decreased (p &lt, 0.05) when the ME levels of diets changed from 11.54 to 12.52 MJ/kg. Meanwhile, the plasma TCHO and HDLC concentrations decreased (p &lt, 0.05) as dietary Met levels increased. Based on the linear-broken line model, the dietary Met requirement of starter Pekin ducks from 1 to 21 days of age for optimal ADG were 0.362% (0.052% supplemental L-Met) at 11.54 MJ ME/kg and 0.468% (0.178% supplemental L-Met) at 12.52 MJ ME/kg, respectively, when crystal L-Met was supplemented to formulate the diets. This suggested that the Met requirement of starter Pekin ducks was affected by dietary ME levels. The data potentially provide theoretical support for the utilization of crystalline L-Met in duck production.

In recent years, different subtypes of highly pathogenic avian influenza (HPAI) viruses caused outbreaks in several poultry types worldwide. Early detection of HPAI virus infection is crucial to reduce virus spread. Previously, the use of a mortality ratio threshold to expedite notification of suspicion in layer farms was proposed. The purpose of this study was to describe the clinical signs reported in the early stages of HPAI H5N8 and H5N6 outbreaks on chicken and Pekin duck farms between 2014 and 2018 in the Netherlands and compare them with the onset of an increased mortality ratio (MR). Data on daily mortality and clinical signs from nine egg‐producing chicken farms and seven Pekin duck farms infected with HPAI H5N8 (2014 and 2016) and H5N6 (2017–2018) in the Netherlands were analysed. In 12 out of 15 outbreaks for which a MR was available, MR increase preceded or coincided with the first observation of clinical signs by the farmer. In one chicken and two Pekin duck outbreaks, clinical signs were observed prior to MR increase. On all farms, veterinarians observed clinical signs of general disease. Nervous or locomotor signs were reported in all Pekin duck outbreaks, but only in two chicken outbreaks. Other clinical signs were observed less frequently in both chickens and Pekin ducks. Compared to veterinarians, farmers observed and reported clinical signs, especially respiratory and gastrointestinal signs, less frequently. This case series suggests that a MR with a set threshold could be an objective parameter to detect HPAI infection on chicken and Pekin duck farms at an early stage. Observation of clinical signs may provide additional indication for farmers and veterinarians for notifying a clinical suspicion of HPAI infection. Further assessment and validation of a MR threshold in Pekin ducks are important as it could serve as an important tool in HPAI surveillance programs.

Background Ducks have a typical avian karyotype that consists of macro- and microchromosomes, but a pair of much less differentiated ZW sex chromosomes compared to chickens. To elucidate the evolution of chromosome architectures between ducks and chickens, and between birds and mammals, we produced a nearly complete chromosomal assembly of a female Pekin duck by combining long-read sequencing and multiplatform scaffolding techniques. Results A major improvement of genome assembly and annotation quality resulted from the successful resolution of lineage-specific propagated repeats that fragmented the previous Illumina-based assembly. We found that the duck topologically associated domains (TAD) are demarcated by putative binding sites of the insulator protein CTCF, housekeeping genes, or transitions of active/inactive chromatin compartments, indicating conserved mechanisms of spatial chromosome folding with mammals. There are extensive overlaps of TAD boundaries between duck and chicken, and also between the TAD boundaries and chromosome inversion breakpoints. This suggests strong natural selection pressure on maintaining regulatory domain integrity, or vulnerability of TAD boundaries to DNA double-strand breaks. The duck W chromosome retains 2.5-fold more genes relative to chicken. Similar to the independently evolved human Y chromosome, the duck W evolved massive dispersed palindromic structures, and a pattern of sequence divergence with the Z chromosome that reflects stepwise suppression of homologous recombination. Conclusions Our results provide novel insights into the conserved and convergently evolved chromosome features of birds and mammals, and also importantly add to the genomic resources for poultry studies.

Trueperella pyogenes is an opportunistic Gram-positive bacterium that induces purulent lesions and abscesses in cattle, small ruminants, and swine. In birds, T. pyogenes infections have been linked to lameness and osteomyelitis in turkeys (Phasianidae) and hepatic fibriscess in turkeys and pigeons (Columbidae). An 18-mo-old backyard rooster with a history of progressive emaciation was submitted to the California Animal Health and Food Safety (CAHFS) laboratory system. At necropsy, unusual numerous miliary granulomas were identified, primarily in the spleen, but granulomas were also observed in air sacs and lungs. Microscopically, few to moderate numbers of granulomas with giant cells were observed in the spleen, lung, air sacs, and crop composed of necrosis and mixed inflammatory cell inflammation including multinucleated giant cells, fibrin deposition, and fibrosis. Trueperella pyogenes was isolated from the air sacs and trachea. Avibacterium paragallinarum PCR was positive from the tracheal swab. A retrospective analysis of CAHFS data on T. pyogenes between 2000 and 2020 identified 24 cases in avian species: chickens (Gallus gallus domesticus; 16/24), turkeys (5/24), Pekin duck (Anas platyrhynchos domesticus; 1/24), parrot (Psittaciformes; 1/24), and pheasant (Phasianidae; 1/24). Although T. pyogenes infection in birds is rare, the clinical signs and gross lesions might be indistinguishable from avian mycobacteriosis in some cases and should be considered in the differential diagnosis.

Pathogenic prion protein (PrPSc), converted from normal prion protein (PrPC), causes prion disease. Although prion disease has been reported in several mammalian species, chickens are known to show strong resistance to prion diseases. In addition to chickens, the domestic duck occupies a large proportion in the poultry industry and may be regarded as a potential resistant host against prion disease. However, the DNA sequence of the prion protein gene (PRNP) has not been reported in domestic ducks. Here, we performed amplicon sequencing targeting the duck PRNP gene with the genomic DNA of Pekin ducks. In addition, we aligned the PrP sequence of the Pekin duck with that of various species using ClustalW2 and carried out phylogenetic analysis using Molecular Evolutionary Genetics Analysis X (MEGA X). We also constructed the structural modeling of the tertiary and secondary structures in avian PrP using SWISS-MODEL. Last, we investigated the aggregation propensity on Pekin duck PrP using AMYCO. We first reported the DNA sequence of the PRNP gene in Pekin ducks and found that the PrP sequence of Pekin ducks is more similar to that of geese than to that of chickens and mallards (wild ducks). Interestingly, Pekin duck PrP showed a high proportion of β-sheets compared to that of chicken PrP, and a high aggregation propensity compared to that of avian PrPs. However, Pekin duck PrP with substitutions of chicken-specific amino acids showed reduced aggregation propensities. To the best of our knowledge, this is the first report on the genetic characteristics of the PRNP sequence in Pekin ducks.

From November 2015 to July 2017, two successive episodes of H5 highly pathogenic avian influenza viruses (HP AIVs) infections occurred on poultry farms in France, mostly in domestic ducks raised for foie gras production in southwestern France. During the two epizootics, epidemiological investigations were carried out on infected farms and control and biosafety measures were implemented in association with surveillance in order to stop the spread of the viruses. Effluents are known to be an important factor in environmental dissemination of viruses, and suitable effluent management is needed to help prevent the spread of epizootics to other farms or pathogen persistence at the farm level. The present study was therefore designed to assess how long infectious A/H5 HP AIVs can persist in naturally or experimentally contaminated fecal slurry samples from ducks, with or without sanitization by lime treatment., Infections by A/H5 and A/H7 avian influenza viruses (AIVs) can cause acute disease and are therefore notifiable in poultry and wild birds. During winter 2015-2016, several cases of infection caused by highly pathogenic (HP) AIVs belonging to the A/H5N1, A/H5N2, and A/H5N9 subtypes were detected in southwestern France. Throughout winter 2016-2017, several cases of infections caused mainly by A/H5N8 HP AIV (A/goose/GD/1/1996, clade 2.3.4.4) were detected across Europe. On both occasions, the viruses were widely detected on palmiped farms in France. This study was designed to evaluate the persistence of A/H5 HP AIV in slurry from various duck productions. This was achieved (i) in the laboratory setting by artificially spiking four AIV-free slurry samples with known amounts of A/H5N9 HP AIV and monitoring virus infectivity, with or without lime treatment to achieve pH 10 or pH 12, and (ii) by sampling slurry tanks on five naturally A/H5N8 HP-contaminated farms. Experimental results in artificially spiked slurry suggested virus survival for 4 weeks in slurry from Muscovy or Pekin duck breeders and for 2 weeks in slurry from ducks for foie gras production during the assisted-feeding period, without lime treatment. Persistence of infectious A/H5N9 HP AIV in all slurry samples after lime treatment at pH 10 or pH 12 was less than 1 week. The A/H5N8 HP AIV persisted in naturally contaminated untreated slurry for 7 weeks. The results obtained provide experimental support for the 60-day storage period without treatment or the 7-day interval after lime treatment defined in French regulations for slurry sanitization. IMPORTANCE From November 2015 to July 2017, two successive episodes of H5 highly pathogenic avian influenza viruses (HP AIVs) infections occurred on poultry farms in France, mostly in domestic ducks raised for foie gras production in southwestern France. During the two epizootics, epidemiological investigations were carried out on infected farms and control and biosafety measures were implemented in association with surveillance in order to stop the spread of the viruses. Effluents are known to be an important factor in environmental dissemination of viruses, and suitable effluent management is needed to help prevent the spread of epizootics to other farms or pathogen persistence at the farm level. The present study was therefore designed to assess how long infectious A/H5 HP AIVs can persist in naturally or experimentally contaminated fecal slurry samples from ducks, with or without sanitization by lime treatment.

Duck hepatitis A virus 3 (DHAV-3) is a wild endemic virus, which seriously endangers the duck industry in China. The present study aims to elucidate the mechanism of duck resistance to DHAV-3 infection. Both resistant and susceptible ducks were challenged with DHAV-3 in this experiment. The histopathological features and serum biochemical indices (ALT and AST) were analyzed to estimate liver injury status at 6, 12, 15, and 24 h post-infection (hpi). The dynamic transcriptomes of liver were analyzed to explain the molecular regulation mechanism in ducks against DHAV-3. The result showed that the liver injury in susceptible ducks was more serious than that in the resistant ducks throughout the four time points. A total of 2,127 differentially expressed genes (DEGs) were identified by comparing the transcriptome of the two populations. The expression levels of genes involved in innate immune response increased rapidly in susceptible ducks from 12 hpi. Similarly, the expression of genes involved in cytokine regulation also increased at the same time points, while the expression levels of these genes in resistant ducks remained similar between the various time points. KEGG enrichment analysis of the DEGs revealed that the genes involved in cytokine regulation and apoptosis were highly expressed in susceptible ducks than that in resistant ducks, suggesting that excessive cytokine storm and apoptosis may partially explain the mechanism of liver injury caused by DHAV-3 infection. Besides, we found that the FUT9 gene may contribute to resistance towards DHAV-3 in resistant ducklings. These findings will provide insight into duck resistance and susceptibility to DHAV-3 infection in the early phases, facilitate the development of a strategy for DHAV-3 prevention and treatment, and enhance genetic resistance via genetic selection in animal breeding.

BackgroundDucks have a typical avian karyotype that consists of macro- and microchromosomes, but a pair of much less differentiated ZW sex chromosomes compared to chicken. To elucidate the evolution of chromosome architectures between duck and chicken, and between birds and mammals, we produced a nearly complete chromosomal assembly of a female Pekin duck by combining long-read sequencing and multiplatform scaffolding techniques.ResultsThe major improvement of genome assembly and annotation quality resulted from successful resolution of lineage-specific propagated repeats that fragmented the previous Illumina-based assembly. We found that the duck topologically associated domains (TAD) are demarcated by putative binding sites of the insulator protein CTCF, housekeeping genes, or transitions of active/inactive chromatin compartments, indicating the conserved mechanisms of spatial chromosome folding with mammals. There are extensive overlaps of TAD boundaries between duck and chicken, and also between the TAD boundaries and chromosome inversion breakpoints. This suggests strong natural selection on maintaining regulatory domain integrity, or vulnerability of TAD boundaries to DNA double-strand breaks. The duck W chromosome retains 2.5-fold more genes relative to chicken. Similar to the independently evolved human Y chromosome, the duck W evolved massive dispersed palindromic structures, and a pattern of sequence divergence with the Z chromosome that reflects stepwise suppression of homologous recombination.ConclusionsOur results provide novel insights into the conserved and convergently evolved chromosome features of birds and mammals, and also importantly add to the genomic resources for poultry studies.

Derzsy&rsquo, s disease causes disastrous losses in domestic waterfowl farms. A genetically variant strain of Muscovy duck parvovirus (MDPV) and goose parvovirus (GPV) was named novel goose parvovirus (NGPV), which causes characteristic syndrome in young ducklings. The syndrome was clinically characterized by deformity in beaks and retarded growth, called short beaks and dwarfism syndrome (SBDS). Ten mule and pekin duck farms were investigated for parvovirus in three Egyptian provinces. Despite low recorded mortality rate (20%), morbidity rate was high (70%), but the economic losses were remarkable as a result of retarded growth and low performance. Isolation of NGPV was successful on primary cell culture of embryonated duck liver cells with a clear cytopathic effect. Partial gene sequence of the VP1 gene showed high amino acids identity among isolated strains and close identity with Chinese strains of NGPV, and low identity with classic GPV and MDPV strains. To the best of our knowledge, this can be considered the first record of NGPV infections in Egypt.

Duck hepatitis A virus (DHAV) causes acute hepatitis and mortality, resulting in high economic losses in the duck farm industry. The current study describes the outbreak of DHAV in vaccinated duck farms in North Egypt during 2019 and molecular characterization of the 3′ untranslated region (UTR) and viral protein VP1 genes. The 30 samples were collected from 7- to 28-day-old commercial Pekin ducks that showed a history of nervous signs and sudden deaths and were on farms in 6 governorates. DHAV was typed by reverse transcription–polymerase chain reaction (RT-PCR) for 3′ UTR and VP1 genes and revealed 20 positive farms, with the first detection of DHAV genotype 3 (DHAV-3) in 18 samples and the classic DHAV-1 in 2 samples. The phylogenetic analysis of VP1 and 3′ UTR genes of the nine selected strains representative of six governorates revealed that seven strains were clustered with DHAV-3 Chinese and Korean-Vietnamese strains within different subgroups with 92.4%–93.7% amino acid identity; such strains were distinguishable from the vaccine strain of DHAV-1 used in Egypt with 74.4% amino acid identity. The other strains were closely related to the DHAV-1 Asian strain and the vaccine strain used in Egypt with 98.7%–99.6% amino acid identity for the VP1 gene with different clustering than that of recently isolated DHAV-1 Egyptian strains. The VP1 gene of DHAV-3 had 1 hypervariable region (HVR) with 10 amino acid mutations compared with DHAV3/DN2/Vietnam/2011, but DHAV-1 had 3 HVRs with 1 amino acid mutation in HVRII compared with the DHAV-1 vaccine strain. In conclusion, a new introduction of DHAV-3 with the classical DHAV-1 was recorded in Pekin duck farms in North Egypt that is genetically distant from the vaccinal strain.

In order to explore the influence of egg-laying regulatory genes on egg production in ducks at different laying stages, Pekin duck and Black Muscovy duck were used in this study, including early laying stage (20–30 weeks old), peak laying period (31–48 weeks old) and late laying stage (49–66 weeks old). Relative quantitative RT-PCR was used to detect the mRNA transcription level of selected egg-laying regulatory genes in the ovary tissues of ducks at different laying stages. Study shows: during the laying period of Pekin duck, ESR1, LRP1, IGF-1 and LHR were involved in the regulation of egg-laying, and the high expression of LRP1 in the late stage could inhibit egg production. Still, the expression products of the other three genes showed promoting effect. During the laying period of Black Muscovy duck, FSH, VLDLR, IGF-1, PRLR, LHR and LRP1 participated in the regulation of egg-laying, in which the expression products of the first five genes could promote egg production, while LRP1 showed inhibitory effect. Through our experiments, these data will provide strong theoretical support for the breeding of Pekin duck and Black Muscovy duck.

Sperm cells have the ability of precise chemotactic and thermotactic movement which is crucial for fertilization, yet the key molecules involved in the detection of different chemical and physical stimuli and guide the sperm cells for proper navigation are not known. This aspect is more complex as each species have their own reproductive identity. Never-the-less, Ca2+-signaling and thus a series of Ca2+-channels seem to coordinate in order to regulate different functions mediated by sperm cells. However, such aspects are controlled by different Ca2+ channels and have species-specific differences. In this work we explored if TRPV channels are endogenously expressed in the mature spermatozoa obtained from avian species. We have used the sperm cells of white pekin duck (Anas platyrhynchos) as a representative avian species to explore the endogenous expression and localization of different TRPV channels. Western blot analysis (WB), flow cytometry, confocal imaging and super resolution imaging was performed for the characterization. Our results strongly suggest the expression and distinct localization of different TRPV channels in the sperm cells. All these TRPV channels are mainly absent in the head region. Only TRPV3 and TRPV4 are sparsely present in the neck region enriched with mitochondria. All these channels (TRPV1-6) are present in the tail region. The differential localization of TRPVs in duck sperm indicate their respective functions relevant in fertilization process of avian sperm. These findings may also have commercial importance in poultry production, cryopreservation of sperm as well as conservation of endangered species through artificial insemination.

At hatching in precocial birds, there are rapid physiological and metabolic phenotypic changes associated with attaining endothermy. During the transition to ex ovo life, thyroid hormone levels naturally increase, peaking at hatching, and then declining. To better understand the role of the natural increase in thyroid hormone at hatching in regulating the developmental trajectory of the Pekin duck's endothermic phenotype, we examined development of O2 consumption (V̇o2) and ventilation (frequency, tidal volume, and minute ventilation) while inhibiting the developmental increase in thyroid hormones that occurs at hatching via administration of the thyroid-peroxidase inhibitor methimazole (MMI) or accelerating the developmental increase via triiodothyronine (T3) supplementation. Animals were dosed only on day 24 of a 28-day incubation period and studied on incubation day 25, during external pipping (EP), and 1-day post hatching (dph). On day 25, there was an increase in V̇o2 in the hyperthyroid treatment compared with the other two treatments. During the EP stage, there was a significant effect of thyroid status on V̇o2 with hyperthyroid V̇o2 being highest and hypothyroid lowest. By 1dph, the supplemented T3 and control animals had similar V̇o2 responses to cooling with comparable thermal neutral zones followed by increased V̇o2. Hypothyroid 1dph hatchlings had a lower resting V̇o2 that did not increase to the same extent as the supplemented T3 and control animals during cooling. During EP, inhibiting the rise in T3 resulted in embryos with lower ventilation frequency and tidal volume than control and supplemented T3 embryos. At 1dph, ventilation frequency of all animals increased during cooling, but tidal volume only increased in supplemented T3 and control hatchlings. Our data supports the role of the late incubation increase in T3 in regulating the systemic development of endothermic metabolic capacity and associated control of ventilation occurring at hatching of the Pekin duck.

Although a number of welfare assessment methods have been developed for poultry, none have been evaluated for use in commercial duck farms. The primary objective of the study was to evaluate the inter-rater reliability and relative accuracy of 4 duck welfare assessment strategies. Over 2 experiments, 12 flocks of commercial meat ducks (5,850 to 6,300 ducks/flock) aged 30 to 34 D were evaluated. During experiment 1, six flocks were evaluated using 2 welfare assessment methods: transect walks (TW) and catch-and-inspect (CAI). During TW, 2 observers walked predetermined transects along the length of the house and recorded the number of ducks per transect that were featherless, were dirty, were lethargic, had bloody feathers, had infected eyes, and/or had plugged nostrils or were found dead. During CAI, a total of 150 ducks per flock were corralled and individually evaluated. The same welfare indicators were assessed using both methods. During experiment 2, six flocks were initially evaluated using CAI, TW, and a distance evaluation (DE; a total of 50 ducks per flock evaluated from a walking distance) and then reassessed within 24 h during the loadout (LO) process. Data were analyzed in SAS (version 9.4) to determine the observer and method effects on the incidence of welfare indicators. Interobserver reliability was high (P > 0.05) across methods for most welfare indicators. The assessment method affected the measured outcome variables in both experiments (P < 0.05). CAI resulted in higher estimated incidences of most welfare indicators than TW (experiment 1 and 2) and LO (experiment 2). DE yielded intermediate results compared with other methods (experiment 2). Results obtained using TW and LO were most similar, the only difference being the number of dead birds observed using each method (P < 0.0001). The average time required for CAI, TW, DE, and LO was 2.40 ± 0.004, 1.12 ± 0.02, 1.54 ± 0.001, 3.56 ± 0.006 h, respectively. Bootstrapping analyses showed that the observed welfare indicator prevalence estimates were affected by the number of transects (TW) and number of birds (CAI) sampled.

The aim of the master thesis was to compare the performance traits of Pekin duck - three hybrid combinations - Cherry Valley, Orvia and Grimaud that were fed to the age of 44 days. The test was performed by the International Poultry Testing Station in Ústrašice. The methodology was based on the guidelines for the implementation of poultry performance testing. Hybrid Cherry Valley achieved the highest fertility of hatching eggs (96%), weight of hatching eggs (88,1 g), live weight at age of 1, 21, 35 and 44 days (age of 44 days - 3 315 g), average daily weight gain (74,1 g), carcass weight (2 217 g) and weight of the breast muscles with skin (636 g). Hybrid Orvia showed the lowest feed conversion ratio ((2 165 g/1 kg of weight gain) and mortality and the highest weight of leg muscle with skin (551 g). Drakes showed higher live weight, average daily weight gain, weight of the breast and leg muscles with skin and lower weight of abdominal fat .

This study was conducted at Poultry farm/Department of Animal Production/College of Agricultural Engineering Sciences/University of Baghdad, were divided into two experiments one during summer and second during winter seasons to study the effect of season and sex on productive performance of Pekin duck reared in an intensive system under harsh Iraqi conditions. A hundred fifty, one day old ducklings were used in each experiment. On 14 day of age, birds were sexed then randomly divided into nine replicates (pens) (5 replicates for females and 4 for males). Results indicated that season has significant effects on studied traits. Body weight, weight gain and food consumption were significantly ( p < 0.01 )higher in birds reared in winter than those reared in summer, whereas no significant differences existed in feed conversion ratio and mortality. Males revealed highly significant ( p< 0.01 ) in body weight and weight gain compared with females in both seasons. Study revealed that pekin duck performance were slightly effected and resisted to acute high temperature during summer. Pursuant to, it can be reared pekin duck in intensive system throughout year in Iraq.

Objective This study was conducted to estimate the genetic parameters and breeding values of breast meat related traits of Pekin ducks. Selection response was also determined by using ultrasound breast muscle thickness (BMT) measurements in combination with bosom breadth (BB) and keel length (KL) values. Methods The traits analyzed were breast meat weight (BMW), body weight (BW), breast meat percentage (BMP) and the three parameters of breast meat (BB, KL, and BMT). These measurements were derived from studying 15,781 Pekin ducks selected from 10 generations based on breast meat weight. Genetic parameters and breeding value were estimated for the analysis of the breeding process. Results Estimated heritability of BMW and BMP were moderate (0.23 and 0.16, respectively), and heritability of BW was high (0.48). Other traits such as BB, KL, and BMT indicated moderate heritability ranging between 0.11 and 0.28. Significant phenotypic correlations of BMW with BW and BMP were discovered (p

In recent years, duck production has been changed from conventional free range and open water outdoors to confinement in birdhouses. And the concept of animal welfare in high stocking density begins to be accepted in China. The search of the relationship between growth performance and flock activity of Pekin ducks with different stocking densities using camera surveillance has great potential as an aid to improving flock management. The aim of this study was to determine the impact of stocking density on growth performance and activity of Pekin duck flocks. Furthermore, the correlation between growth performance and the activity of White Pekin ducks was investigated. Eventually, it will generate an automatic method for monitoring growth performance and stocking density evaluation of Pekin ducks. All ducks (24 days of age, n = 1200) were randomly allotted into 5 stocking density groups of 5 ducks/m2, 6 ducks/m2, 7 ducks/m2, 8 ducks/m2, 9 ducks/m2, with 6 replicates for each group. One group was selected for monitoring the activity of ducks using video recording system. The optical flow measures were extracted to describe the duck flock activity statistically using night video data. On the 24 and 42 days of age, sample collection was conducted for initial and final body weight (BW) measurements respectively. The results showed that the stocking density had significant effects on final BW and weight gain (P 0.05). The stocking density also had significant effects on mean and variance of optical flow produced by duck flock activity throughout the experimental duration. In the last, a significant relation was found between the mean of optical flow and final BW (r2 = +0.87). These results show that the proposed method has potential in automatic growth monitoring and stocking density management of Pekin ducks. It can cut out the bio-security risk and animal stress of having people actually visiting duck houses.

Sindbis virus was first isolated from Culex mosquitoes collected in the village of Sindbis, 30 km north of Cairo in 1952. Sporadic cases were also reported from South Africa in 1963 and Australia in 1967. Human epidemics due to Sindbis virus infection were documented in South Africa in 1974. Sindbis is the prototype virus of the genus Alphavirus in the Togaviridae family. Sindbis virus produces cytopathogenic effects in a wide variety of cell cultures, including continuous lines of VERO, HeLa, BHK-21, and also primary chicken and Pekin duck embryo cells. Since Sindbis virus can infect such a large number of different vertebrate species, other vertebrates besides birds cannot be excluded as possible animal reservoirs. In Sweden, Sindbis virus has been isolated on only three occasions. Virus isolations have been made from Culiseta sp., Cs. morsitans, and Cx. pipiens in Sweden.

Background Lysozyme purified from duck eggs (DEL) has long been used as a model antigen as a counterpoint to the enzyme purified from hen eggs (HEL). However, unlike the single C-type variant found in hen eggs, duck eggs contain multiple isoforms: I, II and III. We recently reported the structures of isoforms I and III from Pekin duck (Anas platyrhynchos) and unequivocally determined the sequences of all three isoforms by mass spectrometry. Here we present the crystal structure of isoform II (DEL-II). Results Lysozyme isoform II was purified from isoforms I and III using ion-exchange and gel-filtration chromatography, then crystallized. X-ray diffraction data were collected to 1.15 Å resolution and the structure of DEL-II was solved by molecular replacement using the structure of DEL-I as the search model. It contains two molecules in the crystallographic asymmetric unit: both molecules display a canonical C-type lysozyme fold and electron density consistent with the expected sequence. The most significant difference between the two molecules concerns different conformations of a surface loop containing one of the expected amino acid differences between the isoforms. Conclusions The structure of DEL-II supports the primary sequence as elucidated by a combination of amino acid sequencing, DNA sequencing and mass spectrometry, with strong electron density confirming it to be an S37G G71R variant of DEL I, and differing from hen egg lysozyme at a total of 21 amino acid positions. Electronic supplementary material The online version of this article (10.1186/s12900-018-0090-7) contains supplementary material, which is available to authorized users.

Pekin ducks are easily reared in a wide range of conditions. As waterfowl, the growth, digestive system and visual perception of Pekin ducks are different to chickens. Generally, ducks are raised f...

Programmed death-1 (PD-1), upon engagement by its ligands, programmed death ligand-1 (PD-L1) and programmed death ligand-2 (PD-L2), provides signals that attenuate adaptive immune responses. Here we describe the identification of the Pekin duck PD-L2 (duPD-L2) and its gene structure. The duPD-L2 cDNA encodes a 321 amino acid protein that has an amino acid identity of 76% and 35% with chicken and human PD-L2, respectively. Mapping of the duPD-L2 cDNA with duck genomic sequences revealed an exonic structure similar to that of the human Pdcd1lg2 gene. Homology modelling of the duPD-L2 protein was compatible with the murine PD-L2 ectodomain structure. Residues known to be important for PD-1 receptor binding of murine PD-L2 were mostly conserved in duPD-L2 within sheets A and G and partially conserved within sheets C and F. DuPD-L2 mRNA was constitutively expressed in all tissues examined with highest expression levels in lung, spleen, cloaca, bursa, cecal tonsil, duodenum and very low levels of expression in muscle, kidney and brain. Lipopolysaccharide treatment of adherent duck PBMC upregulated duPD-L2 mRNA expression. Our work shows evolutionary conservation of the PD-L2 ectodomain structure and residues important for PD-1 binding in vertebrates including fish. The information provided will be useful for further investigation of the role of duPD-L2 in the regulation of duck adaptive immunity and exploration of PD-1-targeted immunotherapies in the duck hepatitis B infection model., Highlights • This is the first report on programmed death ligand-2 (PD-L2) in the Pekin duck. • The duck PD-L2 gene shares a similar exonic structure with the human PD-L2 gene. • Key structural and binding residues of PD-L2 are conserved in vertebrates including fish. • The duck PD-L2 mRNA tissue expression pattern is similar to that of human and mouse PD-L2. • LPS upregulates PD-L2 mRNA in duck PBMC enriched for monocytes and macrophages.

The intertarsal joint is a synovial roll-and-glide joint. Ligament damage and luxations of this joint are often the result of traumatic injury or growth deformities and result in significant functional impairment. A 9-month-old female Pekin duck ( Anas platyrhynchos domesticus) was examined because of progressive, nonweight-bearing lameness of the left leg. Moderate effusive swelling was present at the level of the left intertarsal joint, without radiographic evidence of bone involvement. The duck failed to respond to nonsteroidal anti-inflammatory medications and analgesia and was diagnosed with rupture of the medial collateral ligament. Extracapsular surgical correction using bone tunnels and circumferential nylon suture on the medial aspect of the intertarsal joint led to a complete clinical resolution with normal return to function 2 weeks after surgery. This report reviews the anatomy and function of the intertarsal joint in the duck and details a simple extracapsular repair technique useful in the correction of collateral ligament rupture in this joint of ducks.

It is well known that both British and American Pekin ducks originated from China. However, the populations differ substantially in production performance, but the genetic changes involved are still poorly understood. Herein, we sequenced 24 individual Pekin ducks (eight from each population) with an average sequencing depth of more than 45× for each population (mean coverage of 6.29 per individual). Among these populations from three different countries, we identified a large number of SNPs and indels as well as many unique population variants, which can be used as population-specific molecular markers. Genomic comparisons among the three duck populations revealed many candidate genes as well as pathways and Gene Ontology categories that are putatively associated with meat yield in the British population, growth in the American population and brain development in all three populations. These findings will enable a better understanding of the artificial selection history of Pekin ducks and provide a valuable resource for future research on the breeding of this species.

In a prior study, comparisons of individuals of Anas platyrhynchos with higher/lower reproductive performances showed that the expression of the transmembrane and immunoglobulin domain containing 1 (TMIGD1) gene significantly differed between the two groups. Here, we demonstrate that ducks with the TMIGD1 GG genotype have a significantly higher fertilization rate than other TMIGD1 genotypes. Primers designed based on the TMIGD1 sequence of Pekin duck were able to successfully amplify a TMIGD1 fragment from Tsaiya ducks, and sequencing results indicated that a single nucleotide polymorphism (SNP) of the TMIGD1 gene existed. We also developed a cost-effective method of restriction fragment length polymorphism. Using the above methods, ducks were classified into three genotypes. To identify the relationships between genotypes and traits, we recorded the ducks' performance; to ensure the coverage of the entire duration of the fertile period, the egg collection period was extended to 18 days, and therefore, lower than usual fertilization rates were observed. Further assessment using a high-throughput system showed that the ducks with the GG genotype exhibited the highest fertilization rates among genotypes (P < 0.05). We suggest that TMIGD1 may affect the release of sperm protection factors from the female genital tract, and thus alter fertilization rate. In conclusion, the results of this study demonstrate that the TMIGD1 GG genotype can be used as a new DNA marker to identify animals with high fertilization rates at a young age, a process which could improve farming efficiency.

Bu çalışma, Hatay ili kırsalında halk elinde yetiştirilen pekin ördeklerine ait yumurtaların matematiksel formüller kullanılarak bazı iç ve dış kalite özelliklerinin belirlenmesi amacıyla yapılmıştır. Çalışmada 417 adet pekin ördeği yumurtası kullanılmış ve tartımla bireysel yumurta ağırlık değerleri baz alınarak matematiksel formüller yardımıyla yumurta boyu ve eni, yumurta yüzey alanı, yumurta kabuk ağırlığı ve kalınlığı, gözenek sayısı, yumurta sarı oranı değerleri hesaplanmıştır. Yumurta ağırlığına göre hesaplanan ortalama yumurta boyu 62,48 mm, yumurta eni 43,76 mm, kabuk kalınlığı 0,358 mm, kabuk ağırlığı 6,03 g, yumurta yüzey alanı 81,23 cm2, gözenek sayısı-1 8.915,29 adet, gözenek sayısı-2 7.993,13 adet, gözenek sayısı-3 8.934,70 adet ve sarı oranı %37,68 olarak belirlenmiştir. Ayrıca yumurta dış kalite özelliklerinden şekil indeksi %69,69, elongasyon 1,436, yumurta hacmi 66,38 cm3, gözenek yoğunluğu-1 109,89, gözenek yoğunluğu-2 98,34, gözenek yoğunluğu-3 109,74 gözenek sayısı/cm2 ve kabuk oranı değeri %8,48, yumurta iç kalite özelliklerinden sarı ağırlığı 26,78 g, ak ağırlığı 38,26 g ve ak oranı %53,85 olarak hesaplanmıştır. Sonuç olarak Hatay ilinde halk elinde yetişen pekin ördeklerine ait yumurtaların dış ve iç kalite özellikleri yumurta bütünlüğü bozulmadan ortaya konulmuştur.

H2N2 subtype low pathogenic avian influenza viruses (LPAIVs) have persisted in live bird markets (LBMs) in the Northeastern United States since 2014. Although unrelated to the 1957 pandemic H2N2 lineage, there is concern that the virus could have animal and public health consequences because of high contact with humans and numerous species in the LBM system. The pathogenicity, infectivity, and transmissibility of six LBM H2N2 viruses isolated from three avian species in LBMs were examined in chickens. Two of these isolates were also tested in Pekin ducks and guinea fowl. Full genome sequence was obtained from all 6 isolates and evaluated for genetic markers for host adaptation and pathogenicity in poultry. Clinical signs were not observed in any host with any of the isolates, however one recent isolate was shed at higher titers than the other isolates and had the lowest bird infectious dose of all the isolates tested in all three species. This isolate, A/chicken/NY/19-012787-1/2019, was also the only isolate with a deletion in the stalk region of the neuraminidase protein (NA). This supports the theory that the NA stalk deletion is evidence of adaptation to gallinaceous poultry.