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The present study investigated the effect of supplementing a multi-carbohydrase enzyme complex (MCE) in corn–soy-based diets of Pekin ducks. The treatments were as follows: positive control (PC, 2980 and 3120 kcal/kg for starter and grower, respectively); negative control (NC, −132 kcal/kg energy reduction to PC achieved by reduction of fat and wheat middlings as filler); NC + MCE at 75 ppm (E75); 100 ppm (E100); and 125 ppm (E125) randomly distributed in 10 replicate pens with 25 birds each. Performance was evaluated after 14 and 35 d. On day 36 of the trial, five ducks/pen were processed to evaluate carcass traits. During days 1–14, the PC had a lower (p < 0.01) feed intake compared to all other treatments. At 14 and 35 d of age the NC decreased (p < 0.001) the body weight (BW) of the ducks compared to the PC by −8.3% and −5.3%, respectively. The NC BW was lower (p < 0.001) compared to all MCE-supplemented treatments at 14 and 35 d. The BW of E75, E100, and E125 treatments was not different (p > 0.05) from the PC at both evaluation periods. Cumulatively (1–35 d), the NC resulted in a weight-adjusted FCR increase (p = 0.001) of 9.9% compared to the PC, and the FCR of E75, E100, and E125 were able to recover 72.3%, 66.4%, and 63.5%, respectively, compared to the PC. The carcass and breast weights were lower (p < 0.001) in the NC compared to all other treatments, and no differences (p > 0.05) were observed between the MCE-supplemented treatments and the PC. In conclusion, these results suggest that the MCE supplementation can maintain duck growth performance with no negative effects on carcass traits in energy-reduced corn–soybean meal-based diets. From the results of the trial, 75 ppm MCE delivered the best performance recovery and 125 ppm MCE supplementation had the best % breast yield. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of supplementing a multi-carbohydrase enzyme complex (MCE) in corn–soy-based diets of Pekin ducks. The treatments were as follows: positive control (PC, 2980 and 3120 kcal/kg for starter and grower, respectively); negative control (NC, −132 kcal/kg energy reduction to PC achieved by reduction of fat and wheat middlings as filler); NC + MCE at 75 ppm (E75); 100 ppm (E100); and 125 ppm (E125) randomly distributed in 10 replicate pens with 25 birds each. Performance was evaluated after 14 and 35 d. On day 36 of the trial, five ducks/pen were processed to evaluate carcass traits. During days 1–14, the PC had a lower (p < 0.01) feed intake compared to all other treatments. At 14 and 35 d of age the NC decreased (p < 0.001) the body weight (BW) of the ducks compared to the PC by −8.3% and −5.3%, respectively. The NC BW was lower (p < 0.001) compared to all MCE-supplemented treatments at 14 and 35 d. The BW of E75, E100, and E125 treatments was not different (p > 0.05) from the PC at both evaluation periods. Cumulatively (1–35 d), the NC resulted in a weight-adjusted FCR increase (p = 0.001) of 9.9% compared to the PC, and the FCR of E75, E100, and E125 were able to recover 72.3%, 66.4%, and 63.5%, respectively, compared to the PC. The carcass and breast weights were lower (p < 0.001) in the NC compared to all other treatments, and no differences (p > 0.05) were observed between the MCE-supplemented treatments and the PC. In conclusion, these results suggest that the MCE supplementation can maintain duck growth performance with no negative effects on carcass traits in energy-reduced corn–soybean meal-based diets. From the results of the trial, 75 ppm MCE delivered the best performance recovery and 125 ppm MCE supplementation had the best % breast yield.

Duck hepatitis A virus genotype 3 (DHAV-3) is the major cause of viral hepatitis in ducks in Asia. Previous studies have shown that ducklings younger than 21 days are more susceptible to DHAV-3. To elucidate the mechanism by which age affects the differential susceptibility of Pekin ducks to DHAV-3, intestinal (n = 520), liver (n = 40) and blood (n = 260) samples were collected from control and DHAV-3-infected ducks at 7, 10, 14, and 21 days of age. Comparisons of plasma markers, mortality rates, and intestinal histopathological data showed that the resistance of Pekin ducks to DHAV-3 varied with age. 16 S sequencing revealed that the ileal microbial composition was influenced by age, and this correlation was greater than that recorded for caecal microbes. Candidatus Arthromitus, Bacteroides, Corynebacterium, Enterococcus, Romboutsia, and Streptococcus were the differntially abundant microbes in the ileum at the genus level after DHAV-3 infection and were significantly correlated with 7 differentially expressed genes (DEGs) in 7- and 21-day-old ducklings. 3 immunity-related pathways were significantly different between 7- and 21-day-old ducklings, especially for IFIH1-mediated induction of the interferon-alpha/beta pathway, which induces differential production of CD8(+) T cells and was influenced by a combination of differentially abundant microbiota and DEGs. We found that microbes in the ileum changed regularly with age. The intestinal microbiota was associated with the expression of genes in the liver through IFIH1-mediated induction of the interferon-alpha/beta pathway, which may partially explain why younger ducklings were more susceptible to DHAV-3 infection.

Simple Summary: The body size of ducks reflects their skeletal development and growth status. However, the rapid growth and early large body size of meat ducks negatively affect subsequent slaughter and processing. Therefore, it is necessary to identify candidate genetic markers and genes involved in body size regulation. In this study, we conducted genome-wide association studies (GWASs) on the body length (BL), keel bone length (KBL), neck length (NL), and breast width (BrW) of 42-day-old Pekin ducks (Anas platyrhynchos domestica). The results showed that BL and KBL had similar GWAS signals. Based on these results, we further identified causal haplotypes and candidate genes affecting BL and KBL. This research provides new genetic insights into the growth and development of Pekin ducks and has important implications for their breeding improvement. Body size is an important growth indicator in ducks and is a primary selection criterion for physical improvement. An excessively rapid growth rate in meat ducks can result in excessive body size, which may hinder subsequent processing and slaughter operations. However, only a few molecular markers related to body size have been studied in meat ducks. In this study, we performed a genome-wide association study (GWAS) to identify candidate genes and QTLs affecting body length (BL), keel bone length (KBL), neck length (NL), and breast width (BrW) in Pekin ducks (Anas platyrhynchos domestica). Our results indicate the significant SNP for NL is located within a pseudogene, whereas the significant SNP for BrW is located in an intergenic region. More importantly, our analysis identified a haplotype that was significantly associated with both BL and KBL. This haplotype, containing 48 single-nucleotide polymorphisms (SNPs), is localized within the XKR4 gene. The identification of this haplotype suggests that XKR4 may be a key candidate gene influencing BL and KBL in Pekin ducks. These findings have important implications for the breeding and genetic improvement of Pekin ducks, and provide valuable insights into the genetic architecture of body size traits in this species. [ABSTRACT FROM AUTHOR]

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The intensive raising model for meat duck production has widely adopted cascading cages. However, investigations on low-protein diets for Pekin ducks under this model are scarce. Thus, a 3 × 6 factorial experiment was conducted using six dietary crude protein (CP) levels (17.61%, 16.25%, 15.34%, 14.55%, 13.38%, and 12.64%, analyzed) and three cage layers (lower, middle, and upper). The study aimed to examine the effects of dietary CP reduction with crystalline amino acid supplementation on growth performance, carcass traits, and apparent nutrient digestibility in growing Pekin ducks from 21 to 42 days of age housed at different cage layers. A total of 1620 21-day-old Pekin ducks were randomly divided into 18 groups, each with six replicates of 15 ducks per replicate. Ducks were distributed across different cage layers and were fed one of six experimental diets, respectively, each varying in dietary CP levels but maintaining similar dietary energy and amino acid profiles. The results showed that the reduction in dietary CP levels affected growth performance (p < 0.05), while weight gain, feed intake, and feed/gain of Pekin ducks had no difference among 17.61%, 16.25%, and 15.34% CP groups (p > 0.05). As dietary CP decreased, abdominal fat yield increased (p < 0.05), but breast and leg meat yields were unaffected (p > 0.05). CP intake, nitrogen intake, and nitrogen excretion decreased linearly (p < 0.05) with decreasing dietary CP levels, while apparent nutrient digestibility in Pekin ducks increased proportionally (p < 0.05). Additionally, body weight, weight gain, feed intake, CP intake, nitrogen intake, and nitrogen excretion of Pekin ducks decreased (p < 0.05) due to different cage layers, while carcass characteristics remained unaffected by cage layer (p > 0.05). In summary, it is feasible to reduce the dietary CP level with crystalline amino acid supplementation in growing Pekin ducks from 21 to 42 days of age housed in cascading cages, while the cage layers affected growth performance of ducks. Based on broken-line models, it was determined that the optimal dietary CP requirement for achieving maximum weight gain and feed efficiency in growing Pekin ducks is approximately 15%. [ABSTRACT FROM AUTHOR]

ABSTRACT This study investigates the dynamics of spoilage microflora in duck meat packed in vacuum and air during 9 days of storage. In total, 72 duck carcasses were used in the study. Samples of meat (breasts and thighs, with or without skin) were analysed on days 1, 3, 6 and 9 after packaging in two different atmospheres, at a storage temperature of 3°C ± 1°C. Enterobacteriaceae, coliform bacteria, and E. coli, Total Viable Count, psychrotrophic microorganisms, Lactic Acid Bacteria, Pseudomonas spp. counts, and Brochothrix thermosphacta were determined. As expected, the type of sample and storage length had the greatest influence on microbiological quality (p

ABSTRACT: In the late growth stage of commercial Pekin ducks, a significant increase in feed intake and a decline in body weight gain have been observed, leading to impaired feed conversion efficiency. To address this issue, we investigated alterations in production performance, blood biochemical indices, ileum tissue architecture, and microbial community structure in Pekin ducks. The primary objective was to provide robust data supporting the improvement of meat duck production efficiency during the late growth stage (28–42-days-old). Forty 28-day-old Pekin ducks were randomly assigned to 8 replicates, with five ducks per replicate. The rearing period lasted 14 days, with feed and water provided ad libitum. Our findings indicated a significant increase in Pekin duck body and heart weights with advancing age (P < 0.05). Moreover, serum antioxidant enzyme and high-density lipoprotein concentrations significantly increased, whereas triglyceride levels decreased (P < 0.05). Notably, the height of the ileal villi was significantly reduced (P < 0.05). The microbial community structure of the ileum exhibited significant changes as ducks aged, accompanied by a substantial increase in microbial flora diversity, particularly with the formation of more tightly connected microbial network modules. Time-dependent enrichment was observed in microbial gene functions related to energy metabolism pathways. At the genus level, Sphingomonas and Subdoligranulum have emerged as crucial players in microbial differential functional pathways and network formation. These bacteria likely serve as the key driving factors in the dynamic microbial changes that occur in Pekin ducks over time. Overall, our findings suggest a potential decline in the absorption function of the small intestine and fat deposition performance of Pekin ducks during later growth stages, which may be attributed to the maturation and proliferation of the gut microbial community.

SUMMARY: The objective of this study was to evaluate the effect of a commercially available Bacillus-based direct fed microbial (DFM, Amnil®, United Animal Health, Sheridan, IN) on Pekin duck performance and welfare. The study consisted of 5 dietary treatments, each consisting of 10 replicate pens and 25 straight-run day-of-hatch ducks/pen. The treatments included a commercial-type basal diet (CON), or the basal diet supplemented with 125 ppm (A-125), or 250 ppm (A-250), or 500 ppm (A-500), or 750 ppm (A-750) DFM. On D 14 and 35 performance was evaluated. Gait scores (GS), footpad lesions (FPL), complete cell blood counts, nitrogen digestibility, and total plasma corticosterone levels (CORT) were measured at D 35. The average daily feed intake (ADFI) and feed conversion ratio (FCR) overall were higher in the CON than all other treatments. Body weights did not differ between treatments. The H/L Ratio and total plasma corticosterone levels for CON were higher than all of treatments. Nitrogen digestibility for CON was lower than all other treatments. Gait Scores and Footpad Lesion Scores did not differ between treatments. Utilization of the DFM at any inclusion rate improved feed efficiency, reduced stress susceptibility, and improved nitrogen digestibility. While gait scores, footpad scores, and body weights were not affected by supplementation, feeding this DFM to Pekin ducks can improve their performance and welfare.

ABSTRACT: Pekin duck (Anas platyrhynchos domesticus) is the most widely consumed duck protein with nearly 35 million animals produced annually in the United States and exported worldwide. Pekin ducks are primarily utilized in meat production, so very little information is available about their heritability estimates and genetic correlations for traits related to egg quality. Genetically improving duck populations together with the implementation of more efficient nutritional and management strategies is paramount for the long-term sustainability of the US duck industry. There is a potential opportunity to increase meat duck productivity by improving hatching egg quality. The main objectives of this study were to estimate heritability and genetic correlations for various egg quality traits in a commercial population of Pekin ducks. Egg quality traits for 612 Pekin duck females were measured through 3 time points over 2 generations (GEN) [30, 32, and 35 wk of age (WOA)]. GEN 2 had an additional sampling occurring at 40 WOA. Genetic correlations and heritability estimates were calculated for all the traits using the BLUPF90 software, the Restricted Maximum Likelihood (REML) method, and a pedigree containing 9,418 individuals. All egg quality traits evaluated are moderately to highly heritable ranging from 0.20 for Haugh Unit (HU) and Vitelline Membrane Strength (VMS) to 0.71 for shell ratio (SR). Heritability estimates were calculated for each age of collection and in general heritability increased up to 35 WOA. Genetic correlations between egg quality traits showed a wide range of positive and negative relationships with correlation strengths ranging of −0.80 [yolk ratio (YR) and albumin ratio (AR)] to 0.99 [egg volume (EV) and egg weight (EW)]. The results of this study highlight the potential to improve hatching egg quality within Pekin ducks using a multi-trait selection scheme through direct genetic selection.

Multiple genotypes of highly pathogenic avian influenza (HPAI) H5 clade 2.3.4.4b viruses have caused epizootics in wild birds and poultry. The HPAI H5N1 genotype C virus caused a modest epizootic, whereas the occurrence of the HPAI H5N1 genotype AB virus in 2021 resulted in the largest avian influenza epizootic in Europe to date. Here we studied the pathogenicity of two HPAI H5N1 viruses by experimentally infecting chickens, Pekin ducks, Eurasian wigeons and Barnacle geese. Our study demonstrates that pathogenicity of the H5N1-2021-AB virus is lower in Pekin ducks, Eurasian wigeons and Barnacle geese compared to the H5N1-2020-C virus, whereas virus shedding was high for both viruses. After inoculation with H5N1-2021-C viral antigen expression was higher in the brain of Pekin ducks, Eurasian wigeons and Barnacle geese, which caused higher mortality compared to inoculation with H5N1-2021-AB virus. Subclinical infections occurred in Pekin ducks and Eurasian wigeons and mortality was reduced in Barnacle geese after inoculation with H5N1-2021-AB virus while H5N1-2020-C virus caused high morbidity and mortality in these species. This H5N1-2021-AB virus trait may have contributed to efficient spread of the virus in wild bird populations. Therefore, high mortality, virus shedding and long-lasting viral antigen expression found in Barnacle geese may have increased the risk for introduction into poultry.

The present study investigated the effects of temperature on growth performance, slaughtering traits, meat quality and antioxidant function of Pekin ducks from 21-42 d of age. Single factor analysis of variance was used in this experiment, 144 21 d-old Pekin ducks were randomly allotted to 4 environmentally controlled chambers: T20 (20°C), T23 (23°C), T26 (26°C) and T29 (29°C), with 3 replicates in each group (12 ducks in each replicate), the relative humidity of all groups is 74%. During the 21-day trial period, feed and water were freely available. At 42 d, the BW (body weight) and ADG (average daily gain) of T26 were significantly lower than T20 (p < 0.05), and the T29 was significantly lower than T20 and T23 (p < 0.05). The ADFI (average daily feed intake) of T26 and T29 were significantly lower than T20 and T23 (p < 0.05). Compared to the T29, the T20 showed a significant increase oblique body length and chest width, and both the keel length and thigh muscle weight significantly increased in both the T20 and T23, while the pectoral muscle weight increased significantly in other groups (p < 0.05). The cooking loss of the T29 was the lowest (p < 0.05). The T-AOC (total antioxidant capacity) of T29 was significantly higher than the other groups (p < 0.05), the SOD (superoxide dismutase) in the T29 was significantly higher than the T23 and T26 (p < 0.05). In conditions of 74% relative humidity, the BW and ADFI of Pekin ducks significantly decrease when the environmental temperature exceeds 26°C, and the development of body size and muscle weight follows this pattern. The growth development and serum redox state of Pekin ducks are more ideal and stable at temperatures of 20°C and 23°C. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of adding 500 g/t rosemarinic acid (RA) to the diet on the growth performance, serum biochemistry, antioxidant and immune functions of Pekin ducks. A total of 210 healthy 1-day-old Pekin ducks were randomly divided into 2 groups: control group (feeding basal diet) and experimental group (feeding basal diet + 500 g/t RA), with an experimental pe‐ riod of 42 d. The growth performance, serum antioxidation immune function and liver biochemical indi‐ ces were measured. The results showed that: ① compared with the control group, the Pekin ducks in the RA group exhibited extremely increase in their final weights and average daily weight gain at both 21 and 42 days (P<0.01), while there was a tendency for the mortality rate of Pekin ducks to decrease (P< 0.10). ② Compared with the control group, the serum catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) levels of the Pekin ducks in the RA group were extremely increased (P< 0.01), and the levels of malondialdehyde (MDA) were extremely decreased (P<0.01). ③ The serum levels of immunoglobulin M (IgM) of the Pekin ducks in the RA group were significantly higher (P<0.05) than the control group, immunoglobulin A (IgA) and immunoglobulin G (IgG) of the Pekin ducks in the RA group were extremely higher (P<0.01) ④ Compared with the control group, total protein (TP) and albumin (ALB) content of the Pekin ducks in the RA group were extremely higher than the control group (P<0.01), and the levels of alkaline phospha‐ tase (ALP) and total cholesterol (TC) were extremely lower (P<0.01). Moreover, triglycerides (TG) levels in the livers of the RA group were significantly lower than the control group (P<0.05). In conclusion, di‐ etary addition of 500 g/t RA improved the growth performance, antioxidant capacity, immune function and hepatic protein synthesis in Pekin ducks. [ABSTRACT FROM AUTHOR]

ABSTRACT: Pekin ducks are exposed to stressors such as heat stress, enteric pathogens, mycotoxins, and other environmental stressors. We know from wild bird literature that birds communicate through vocalizations. We hypothesized that Pekin ducks would have a diverse repertoire that is affected by the sex, social group, and specific stimuli. We utilized adult Pekin ducks to develop a vocal repertoire. We placed 1 to 4 ducks of varying sexes into a sound chamber with various stimuli used to encourage new vocalizations. Birds were recorded for 20 min with several variations of number and sexes of ducks. Once the ducks were recorded each vocalization that was clipped was named based on a predetermined naming system. We characterized the vocal system of the ducks under each stimulus and social treatment in 4 ways: overall call rates, call diversity, call repertoire, and call spectral properties. In all cases, normality of residuals and homogeneity of variances for GLM and ANOVA models were confirmed using Proc Univariate (SAS v9.4) where a p ≤ 0.05 was considered significant. We found that Pekin ducks produce up to 16 different vocalizations. The treatments had a significant effect on the overall rate of calls given by the ducks (ANOVA: F6,31 = 8.55, p < 0.0001). Ducks produced the most calls by far when someone was sitting in the chamber with them (30.04 ± 4.45 calls/min). For call diversity, we found that there was a significant main effect of hen number (F218 = 12.21, p = 0.0004) but no main effect of drake number (F3,18 = 3.04, p = 0.0555). Cluster analyses indicated that certain types of calls were given under specific conditions. There were generally 6 major clusters of vocal repertoires (R-square = 0.899, Cubic Clustering Criterion = 9.30). Our results suggest that Pekin ducks are affected by the types of stimuli and social environment in how much they vocalize and in the properties of the calls they use. In addition, males and females differ somewhat in the repertoire of the calls they use, and in the spectral properties of their calls.

Simple Summary: Fat deposition ability is an important index with which to evaluate meat-producing ducks. Ducks with the same diet and environment can present with differences in fat deposition ability if they have diverse genetic backgrounds. Nankou 1 Pekin ducks and Jingdian Pekin ducks are common strains of Pekin duck, a famous, large-sized meat-producing duck breed with a fast growth rate, high feed conversion rate and short growth cycle. The aim of this study is to investigate the differences in slaughtering performance and transcriptome profiles of different strains of Pekin ducks, so as to explore the mechanisms regulating fat deposition in ducks. The results showed that Nankou 1 had greater abdominal fat and subcutaneous fat content than Jingdian ducks, and that the gene expression differences between these two strains of ducks may be the cause of the differences in fat deposition. This study lays a foundation for exploring the regulatory mechanism of fat deposition in ducks and provides a theoretical basis for breeding high-quality meat-producing ducks. Subcutaneous fat deposition is an important index with which to evaluate meat-producing ducks, and affects their meat quality and feed conversion rate. Studying the differentially expressed genes in subcutaneous fat will help to comprehensively understand the potential mechanisms regulating fat deposition in ducks. In this study, 72 Nankou 1 Pekin Ducks and 72 Jingdian Pekin Ducks (half male and half female) at 42 days of age were selected for slaughter performance and transcriptome analysis. The results showed that the breast-muscle yield of Nankou 1 ducks was significantly higher than that of Jingdian ducks, but that the abdominal fat yield and subcutaneous fat yield were higher than that of Jingdian ducks. Thousands of DEGs, including many important genes involved in fat metabolism regulation, were detected by transcriptome. KEGG enrichment analysis showed that the DEGs were significantly enriched on pathways such as regulation of lipolysis in adipocytes, primary bile acid biosynthesis, and biosynthesis of unsaturated fatty acids. SCD, FGF7, LTBP1, PNPLA3, ADCY2, and ACOT8 were selected as candidate genes for regulating subcutaneous fat deposition. The results indicated that Nankou 1 had superior fat deposition ability compared to Jingdian ducks, and that the candidate genes regulated fat deposition by regulating fat synthesis and decomposition. [ABSTRACT FROM AUTHOR]

Developer ducks are ducks being reared for breeding. Like breeder candidate chickens, they are raised with appropriate light and feed programs. A commercial Pekin duck (Anas platyrhynchos domesticus) developer flock experienced an extraordinary, elevated mortality event at 6 wk of age. Weekly mortality rate that week was 162 ducklings out of a flock of 6420 (2.5%). Mortality jumped to 988 (15.4%) ducklings the next week. On first elevated mortality, six dead ducks from that flock were submitted for diagnostic investigation at Michigan State University Veterinary Diagnostic Laboratory. Myocarditis, pale striping or diffuse pallor of the epicardium, was grossly evident in five of the six submitted ducklings. All of the ducklings had hydropericardium, three had ascites, and three had congested meninges. Histology confirmed myocarditis with myocardial necrosis. Cerebrum and brainstem had lymphocytic vasculitis with rare neuronal necrosis in affected areas, as well as Purkinje cells in the cerebellum. West Nile virus was confirmed by PCR the day after submittal and by immunohistochemistry soon thereafter. Reporte de caso- Infección por el virus del Nilo occidental en una parvada en desarrollo de patos Pekin (Anas platyrhynchos domesticus) reproductores. Los patos reproductores en desarrollo son patos que se crían para la reproducción. Al igual que los pollos candidatos para reproducción, se crían con programas de iluminación y alimentación adecuados. Una parvada comercial en desarrollo de pato Pekín (Anas platyrhynchos domesticus) experimentó un evento de mortalidad elevada y extraordinaria a las seis semanas de edad. La tasa de mortalidad semanal de esa semana fue de 162 patitos de una parvada de 6420 (2.5%). La mortalidad se elevó a 988 (15.4%) patitos la semana siguiente. En el primer aumento de mortalidad, seis patos muertos de esa bandada fueron enviados para una investigación de diagnóstico en el Laboratorio de Diagnóstico Veterinario de la Universidad Estatal de Michigan. La miocarditis, caracterizada por rayas pálidas o palidez difusa del epicardio, fue evidente en cinco de los seis patitos presentados. Todos los patitos mostraron hidropericardio, tres tenían ascitis y tres tenían meninges congestionadas. La histología confirmó miocarditis con necrosis miocárdica. El cerebro y el tronco del encéfalo tenían vasculitis linfocítica con rara necrosis neuronal en las áreas afectadas, así como de las células de Purkinje en el cerebelo. El virus del Nilo Occidental se confirmó mediante PCR el día después de la llegada al laboratorio y mediante inmunohistoquímica poco tiempo después. [ABSTRACT FROM AUTHOR]

ABSTRACT: As the most prevalent pathogen of duck viral hepatitis (DVH), duck hepatitis A virus genotype 3 (DHAV-3) has caused huge economic losses to the duck industry in China. Herein, we obtained whole-transcriptome sequencing data of susceptible (S) and resistant (R) Pekin duckling samples at 0 h, 12 h, and 24 h after DHAV-3 infection. We found that DHAV-3 infection induces 5,396 differentially expressed genes (DEGs), 85 differentially expressed miRNAs (DEMs), and 727 differentially expressed lncRNAs (DELs) at 24 hpi in S vs. R ducks, those upregulated genes were enriched in inflammation and cell communications pathways and downregulated genes were related to metabolic processes. Upregulated genes showed high connectivity with the miR-33, miR-193, and miR-11591, and downregulated genes were mainly regulated by miR-2954, miR-125, and miR-146b. With the construction of lncRNA-miRNA-mRNA axis, we further identified a few aberrantly expressed lncRNAs (e.g., MSTRG.36194.1, MSTRG.50601.1, MSTRG.34328.7, and MSTRG.29445.1) that regulate expression of hub genes (e.g., THBD, CLIC2, IL8, ACOX2, GPHN, SMLR1, and HAO1) by sponging those highly connected miRNAs. Altogether, our findings defined a dual role of ncRNAs in immune and metabolic regulation during DHAV-3 infection, suggesting potential new targets for treating DHAV-3 infected ducks.

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

Body size is an important growth indicator in ducks and is a primary selection criterion for physical improvement. An excessively rapid growth rate in meat ducks can result in excessive body size, which may hinder subsequent processing and slaughter operations. However, only a few molecular markers related to body size have been studied in meat ducks. In this study, we performed a genome-wide association study (GWAS) to identify candidate genes and QTLs affecting body length (BL), keel bone length (KBL), neck length (NL), and breast width (BrW) in Pekin ducks (Anas platyrhynchos domestica). Our results indicate the significant SNP for NL is located within a pseudogene, whereas the significant SNP for BrW is located in an intergenic region. More importantly, our analysis identified a haplotype that was significantly associated with both BL and KBL. This haplotype, containing 48 single-nucleotide polymorphisms (SNPs), is localized within the XKR4 gene. The identification of this haplotype suggests that XKR4 may be a key candidate gene influencing BL and KBL in Pekin ducks. These findings have important implications for the breeding and genetic improvement of Pekin ducks, and provide valuable insights into the genetic architecture of body size traits in this species.

The intensive raising model for meat duck production has widely adopted cascading cages. However, investigations on low-protein diets for Pekin ducks under this model are scarce. Thus, a 3 × 6 factorial experiment was conducted using six dietary crude protein (CP) levels (17.61%, 16.25%, 15.34%, 14.55%, 13.38%, and 12.64%, analyzed) and three cage layers (lower, middle, and upper). The study aimed to examine the effects of dietary CP reduction with crystalline amino acid supplementation on growth performance, carcass traits, and apparent nutrient digestibility in growing Pekin ducks from 21 to 42 days of age housed at different cage layers. A total of 1620 21-day-old Pekin ducks were randomly divided into 18 groups, each with six replicates of 15 ducks per replicate. Ducks were distributed across different cage layers and were fed one of six experimental diets, respectively, each varying in dietary CP levels but maintaining similar dietary energy and amino acid profiles. The results showed that the reduction in dietary CP levels affected growth performance (p < 0.05), while weight gain, feed intake, and feed/gain of Pekin ducks had no difference among 17.61%, 16.25%, and 15.34% CP groups (p > 0.05). As dietary CP decreased, abdominal fat yield increased (p < 0.05), but breast and leg meat yields were unaffected (p > 0.05). CP intake, nitrogen intake, and nitrogen excretion decreased linearly (p < 0.05) with decreasing dietary CP levels, while apparent nutrient digestibility in Pekin ducks increased proportionally (p < 0.05). Additionally, body weight, weight gain, feed intake, CP intake, nitrogen intake, and nitrogen excretion of Pekin ducks decreased (p < 0.05) due to different cage layers, while carcass characteristics remained unaffected by cage layer (p > 0.05). In summary, it is feasible to reduce the dietary CP level with crystalline amino acid supplementation in growing Pekin ducks from 21 to 42 days of age housed in cascading cages, while the cage layers affected growth performance of ducks. Based on broken-line models, it was determined that the optimal dietary CP requirement for achieving maximum weight gain and feed efficiency in growing Pekin ducks is approximately 15%.

This study aimed to investigate the effect of different egg weights on egg external quality characteristics and hatching performance in Pekin ducks. A total of 800 eggs were divided into three weight categories: "light" (Lo; 82 g). Parameters indicating egg external quality characteristics were calculated. Eggs were incubated and on the 25th day, transferred to the incubator for hatching. The mean egg weight for light, medium, and heavy categories were 70.25 g, 78.47 g, and 85.17 g, respectively (P

Dietary threonine (Thr) deficiency enhances triglyceride (TG) deposition in the liver of Pekin ducks, which injures hepatic function and impairs growth performance. However, the underlying molecular mechanisms remain unclear. In the present study, we investigated the effects of dietary Thr deficiency on the expressions of proteins and phosphoproteins in liver of Pekin ducks, to identify the underlying molecular changes. A total of 300 one-day-old ducklings were divided into 3 groups with 10 replicates of 10 birds. All ducks were fed corn-wheat-peanut meal diets containing 0.46%, 0.71%, and 0.96% Thr, respectively, from 1 to 21 days of age. Growth performance, serum parameters, hepatic TG content, and expression of genes involved in lipid metabolism of Pekin ducks were determined. A Thr deficiency group (Thr-D, 0.46% Thr) and a Thr sufficiency group (Thr-S, 0.71% Thr) were selected for subsequent proteomic and phosphoproteomic analysis. The results showed that Thr-D reduced the growth performance (P

In Egypt, poultry farms are still experiencing pressure from the avian influenza viruses H5N1, H5N8, and H9N2, as well as economic losses from direct viral infection or sharing other diseases that increase respiratory complications. Despite the administration of multiple vaccines against these viruses, protective immunity cannot develop due to frequent virus mutation and changes due to immunological pressure or genetic mixing. In this study, a six-weeks-old flock of Pekin ducks showed sudden mortality without any symptoms, while the still survived birds showed depression, mild to severe respiratory and/or nervous symptoms and greenish diarrhea. The mortality rate reached 25.4% in two weeks. Postmortem lesion included severely congested organs, tracheitis, pneumonia, massive hemorrhages on coronary fat and heart muscles, thymic hyperplasia, necrosis, and hemorrhages on pancreas. Liver samples were H5 positive by PCR, and sequences identified two isolates with the accession numbers MW917155 and MW917160. The phylogenetic analysis and identity table of the obtained two isolates demonstrated their relationship to the clade 2.3.4.4.1, which includes Egyptian isolates from ducks, goose, and chickens from 2017 to 2019. Our results showed clinical manifestation as well as molecular techniques to support the diagnosis of ducks infected with the highly pathogenic avian influenza (HPAI) virus. Furthermore, our findings revealed a link between our isolates and earlier local and worldwide isolates, as well as a match with the vaccines used in Egypt. Further coordinated national investigations on the prevalence and variations of HPAI virus infection in Egyptian poultry farms as well as the efficacy of used vaccinations are advised. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effect of adding sonicated coconut shell liquid smoke to pekin duck jerky with different storage times at room temperature and vacuum packed. Ground duck jerky is made from Pekin duck meat (Anas platyrhynchos domesticus) soaked in coconut shell liquid smoke (CSLS) which has been sonicated for 20 minutes and seasoned with spices such as garlic, galangal, coriander, tamarind, salt, and coconut sugar. A laboratory experiment was done using a completely randomized design (CRD) consisting of 5 treatments (control: 0 day storage period, T1: 7 days, T2: 14 days, T3: 21 days, and T4: 28 days) and 4 replications. The results showed that the addition of sonicated CSLS with differences in the shelf life of pekin ground duck jerky had a significant effect (P<0.01) on pH, texture, color L, a*, b*, Aw, water content, fat, carbohydrates by difference, thiobarbituric acid (TBA), and iodine number. Had a significant effect (P<0.05) on ash content, and had no significant effect on Water Holding Capacity (WHC), protein content, and organoleptic quality. It was concluded that storing ground duck jerky for 14 days at room temperature and vacuum packed did not show any damage to pH, water activity, water content, fat, protein, TBA and iodine number, and did not occur rancidity. [ABSTRACT FROM AUTHOR]

BackgroundPrion diseases have been extensively reported in various mammalian species and are caused by a pathogenic prion protein (PrPSc), which is a misfolded version of cellular prion protein (PrPC). Notably, no cases of prion disease have been reported in birds. Single nucleotide polymorphisms (SNPs) of the prion protein gene (PRNP) that encodes PrP have been associated with susceptibility to prion diseases in several species. However, no studies on PRNP polymorphisms in domestic ducks have been reported thus far.MethodTo investigate PRNP polymorphisms in domestic ducks, we isolated genomic DNA from 214 Pekin duck samples and sequenced the coding region of the Pekin duck PRNP gene. We analyzed genotype, allele, and haplotype distributions and linkage disequilibrium (LD) among the SNPs of the Pekin duck PRNP gene. In addition, we evaluated the effects of the one non-synonymous SNP on the function and structure of PrP using the PROVEAN, PANTHER, SNPs & GO, SODA, and AMYCO in silico prediction programs.ResultsWe found five novel SNPs, c.441 T > C, c.495 T > C, c.582A > G, c.710C > T(P237L), and c.729C > T, in the ORF region of the PRNP gene in 214 Pekin duck samples. We observed strong LD between c.441 T > C and c.582A > G (0.479), and interestingly, the link between c.495 T > C and c.729C > T was in perfect LD, with an r2 value of 1.0. In addition, we identified the five major haplotype frequencies: TTACC, CTGCC, CTACC, CCGCT, and CTATC. Furthermore, we found that the non-synonymous SNP, c.710C > T (P237L), had no detrimental effects on the function or structure of Pekin duck PrP. However, the non-synonymous SNP had deleterious effects on the aggregation propensity and solubility of Pekin duck PrP compared with wildtype Pekin duck PrP.ConclusionTo the best of our knowledge, this study is the first report on the genetic characteristics of PRNP SNPs in Pekin ducks.

This study aimed to investigate the effect of different egg weights on egg external quality characteristics and hatching performance in Pekin ducks. A total of 800 eggs were divided into three weight categories: "light" (Lo; <76 g), "medium" (Me; 76-82 g), and "heavy" (Hi; >82 g). Parameters indicating egg external quality characteristics were calculated. Eggs were incubated and on the 25th day, transferred to the incubator for hatching. The mean egg weight for light, medium, and heavy categories were 70.25 g, 78.47 g, and 85.17 g, respectively (P<0.001). As egg weight increased, there was a significant decrease in shell thickness (P<0.001). The effect of different egg sizes on fertility was insignificant. The hatchability of fertile eggs was higher in the light and medium categories compared to the heavy category (P<0.05). Egg weight had a significant effect on early embryonic mortality rate (P<0.05) and chick hatch weight (P<0.001). In conclusion, different egg weights have varying effects on egg external quality parameters in Pekin ducks. Although heavy eggs produce chicks with higher weights, lighter or medium-weight eggs may be more advisable for incubation due to their better hatchability. [ABSTRACT FROM AUTHOR]

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<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<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. [ABSTRACT FROM AUTHOR]

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.

In this study, Tembusu virus (TMUV) 1080905 isolate was isolated from 29-week-old breeder Pekin ducks in Taiwan in 2019. Clinical history showed that the clinical features were a temporary decrease in egg production, decline of feed uptake, watery diarrhea, nervous signs and sporadic mortality. Necropsy findings were congestion, hyperemia and hemorrhage of the ovary follicles, swollen spleen and deposits of fibrinous exudate on the pericardium and the liver capsule. The polyprotein gene of TMUV 1080905 was 10,278 nucleotides long, encoded 3425 amino acids and exhibited 99.3% nucleotide similarity and 99.7% amino acid similarity with Taiwanese mosquito-derived isolate TMUV TP1906. Our phylogenetic analysis revealed that the Taiwanese TMUVs were grouped together with Malaysian TMUV (chicken-derived Sitiawan virus and the TMUV prototype strain MM1775). To our knowledge, this is the first report of duck-derived TMUV in Taiwan. Further studies of the pathogenicity and host range of the TMUV 1080905 are required. Research Highlights First identification of Tembusu virus in Pekin ducks in Taiwan. Investigation of the phylogeny of TMUV 1080905 isolate from Pekin ducks in Taiwan.

Angel wing is a developmental wing deformity that can influence breeding and reproduction in the commercial duck industry. The nutrition foundation of angel wing trait was initially explored, but the genetic basic remains poorly understood. In this study, we identified candidate genes and single‐nucleotide polymorphisms (SNPs) associated with angel wing trait in Pekin ducks using a genome‐wide association study (GWAS) and selective sweep analysis. The GWAS results showed that nine SNPs across five chromosomes were significantly correlated with the angel wing trait. In total, 468 selection signals were shown between the angel wing ducks and normal ducks, and these signals harbored 154 genes, which were enriched in the nervous system and metabolism. This study provides the new insights into the genetic factors that may influence duck angel wing. [ABSTRACT FROM AUTHOR]

Skeletal muscle is an important economic trait in duck breeding; however, little is known about the molecular mechanisms of its embryonic development. Here, the transcriptomes and metabolomes of breast muscle of Pekin duck from 15 (E15_BM), 21 (E21_BM), and 27 (E27_BM) days of incubation were compared and analyzed. The metabolome results showed that the differentially accumulated metabolites (DAMs), including the up-regulated metabolites, l-glutamic acid, n-acetyl-1-aspartylglutamic acid, l-2-aminoadipic acid, 3-hydroxybutyric acid, bilirubin, and the significantly down-regulated metabolites, palmitic acid, 4-guanidinobutanoate, myristic acid, 3-dehydroxycarnitine, and s-adenosylmethioninamine, were mainly enriched in metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of cofactors, protein digestion and absorption, and histidine metabolism, suggesting that these pathways may play important roles in the muscle development of duck during the embryonic stage. Moreover, a total of 2142 (1552 up-regulated and 590 down-regulated), 4873 (3810 up-regulated and 1063 down-regulated), and 2401 (1606 up-regulated and 795 down-regulated) DEGs were identified from E15_BM vs. E21_BM, E15_BM vs. E27_BM and E21_BM vs. E27_BM in the transcriptome, respectively. The significantly enriched GO terms from biological processes were positive regulation of cell proliferation, regulation of cell cycle, actin filament organization, and regulation of actin cytoskeleton organization, which were associated with muscle or cell growth and development. Seven significant pathways, highly enriched by FYN, PTK2, PXN, CRK, CRKL, PAK, RHOA, ROCK, INSR, PDPK1, and ARHGEF, were focal adhesion, regulation of actin cytoskeleton, wnt signaling pathway, insulin signaling pathway, extracellular matrix (ECM)-receptor interaction, cell cycle, and adherens junction, which participated in regulating the development of skeletal muscle in Pekin duck during the embryonic stage. KEGG pathway analysis of the integrated transcriptome and metabolome indicated that the pathways, including arginine and proline metabolism, protein digestion and absorption, and histidine metabolism, were involved in regulating skeletal muscle development in embryonic Pekin duck. These findings suggested that the candidate genes and metabolites involved in crucial biological pathways may regulate muscle development in the Pekin duck at the embryonic stage, and increased our understanding of the molecular mechanisms underlying the avian muscle development. [ABSTRACT FROM AUTHOR]

Subcutaneous fat deposition is an important index with which to evaluate meat-producing ducks, and affects their meat quality and feed conversion rate. Studying the differentially expressed genes in subcutaneous fat will help to comprehensively understand the potential mechanisms regulating fat deposition in ducks. In this study, 72 Nankou 1 Pekin Ducks and 72 Jingdian Pekin Ducks (half male and half female) at 42 days of age were selected for slaughter performance and transcriptome analysis. The results showed that the breast-muscle yield of Nankou 1 ducks was significantly higher than that of Jingdian ducks, but that the abdominal fat yield and subcutaneous fat yield were higher than that of Jingdian ducks. Thousands of DEGs, including many important genes involved in fat metabolism regulation, were detected by transcriptome. KEGG enrichment analysis showed that the DEGs were significantly enriched on pathways such as regulation of lipolysis in adipocytes, primary bile acid biosynthesis, and biosynthesis of unsaturated fatty acids. SCD, FGF7, LTBP1, PNPLA3, ADCY2, and ACOT8 were selected as candidate genes for regulating subcutaneous fat deposition. The results indicated that Nankou 1 had superior fat deposition ability compared to Jingdian ducks, and that the candidate genes regulated fat deposition by regulating fat synthesis and decomposition.

ABSTRACT: This study aimed to investigate the effect of a high-fat diet on the growth performance, serum, liver, and skin lipid metabolism as well as the fatty acids composition of liver and skin fat in Pekin ducks from 10 to 40 d of age based on a pair-fed group. Two hundred forty healthy male ducks (10 d old, 470.53 ± 0.57 g) were randomly divided into 3 groups (8 replicates per cage of 10 ducks): a normal diet (ND, 3% fat), a high-fat diet (HFD, 9% fat), and a pair-fed diet (PFD, given the ND in an amount equal to that consumed of the HFD to eliminate the effects of feed intake). The results were as follows: compared to ND feeding, HFD feeding significantly decreased (P < 0.05) the feed intake and feed:gain ratio (F:G), along with serum triglyceride and nonesterified fatty acid contents. When compared with the ND and PFD, the HFD significantly decreased (P < 0.05) the liver weight and inhibited hepatic de novo lipogenesis (glucose-6-phosphate dehydrogenase and malate dehydrogenase activities), β-oxidation (carnitine palmitoyltransferase-1 content), and decreased saturated fatty acids and monounsaturated fatty acids deposition. Moreover, the HFD significantly increased (P < 0.05) the total fat content, lipid droplet area, and polyunsaturated fatty acids (PUFAs) content in the liver, as well as the abdominal fat weight, subcutaneous fat weight, the total fat and PUFAs content in skin fat. These results suggested that the HFD improved feed efficiency, which was related to HFD feeding inhibiting hepatic de novo lipogenesis and β-oxidation and promoting the deposition of fat in skin as well as altering the fatty acids composition of the liver and skin fat in Pekin ducks.

Advances in molecular genetics have led to the identification of genes or markers that affect many morphological and physiological characteristics of farm animals. The molecular basis of these traits is revealed by functional genomic methods and provides opportunities to develop genetic improvement programs in farm animals through marker assisted selection (MAS). Several candidate genes are being studied with the aim of increasing various yield and reproductive performances in animals through MAS. One of these candidate genes is the growth hormone gene. The main purpose of this study was to investigate polymorphisms in the 2nd, 3rd and 4th introns of the growth hormone gene in Pekin ducks. For this purpose, blood samples taken from a total of 117 adult Pekin ducks of both sexes (79 males and 38 females) raised in Bursa Uludag University Faculty of Agriculture Agricultural Application and Research Farm were used as material. Genetic polymorphism in the 2nd, 3rd and 4th introns of the growth hormone gene was investigated using the BsmF1 restriction enzyme in the PCR-RFLP method with three primer pairs. Samples were carried out in 2% agarose gel electrophoresis to separate the DNA fragments obtained after the digestion. As a result of the researches, polymorphism was determined only in the fragment amplified from the 2nd intron region. As a result of the digestion of the amplified fragment from the 2nd intron region with BsmF1 restriction enzyme, three genotypes, namely TT (765 bp), CT (765, 593 and 172 bp) and CC (593 and 172 bp) were determined in this region and the frequencies of the T and C alleles were calculated as 0.75 and 0.25, respectively. Since the difference between the values observed in the 2nd intron region of the growth hormone gene and the expected values in the studied population was not statistically significant (P>0.05), it was understood that the population in studied was in Hardy-Weinberg equilibrium. No genetic variation was observed in the 3rd and 4th introns. PCR products belonging to the 442 bp and 1378 bp regions of the 3rd and 4th introns of the growth hormone gene, respectively, were also treated with BsmF1 restriction enzyme, but the cleavage region of this enzyme was not found, so there was only one genotype was obtained in the 3rd and 4th introns of the studied population. Therefore, it was understood that these two regions are monomorphic in terms of BsmF1 locus. The genotypic variation shown in the 2nd intron region of the growth hormone gene in this and previous studies also reveals the need for further studies on the relationships between this region and various yields. [ABSTRACT FROM AUTHOR]

In this study, Tembusu virus (TMUV) 1080905 isolate was isolated from 29-week-old breeder Pekin ducks in Taiwan in 2019. Clinical history showed that the clinical features were a temporary decrease in egg production, decline of feed uptake, watery diarrhea, nervous signs and sporadic mortality. Necropsy findings were congestion, hyperemia and hemorrhage of the ovary follicles, swollen spleen and deposits of fibrinous exudate on the pericardium and the liver capsule. The polyprotein gene of TMUV 1080905 was 10,278 nucleotides long, encoded 3425 amino acids and exhibited 99.3% nucleotide similarity and 99.7% amino acid similarity with Taiwanese mosquito-derived isolate TMUV TP1906. Our phylogenetic analysis revealed that the Taiwanese TMUVs were grouped together with Malaysian TMUV (chicken-derived Sitiawan virus and the TMUV prototype strain MM1775). To our knowledge, this is the first report of duck-derived TMUV in Taiwan. Further studies of the pathogenicity and host range of the TMUV 1080905 are required. First identification of Tembusu virus in Pekin ducks in Taiwan. Investigation of the phylogeny of TMUV 1080905 isolate from Pekin ducks in Taiwan. [ABSTRACT FROM AUTHOR]

Abstract Background Although methionine (Met), the first-limiting dietary amino acid, has crucial roles in growth and regulation of lipid metabolism in ducks, mechanisms underlying are not well understood. Therefore, the objective was to use dietary Met deficiency to investigate the involvement of Met in lipid metabolism and fat accumulation of Pekin ducks. Methods A total of 150 male Pekin ducks (15-d-old, 558.5 ± 4.4 g) were allocated into 5 groups (6 replicates with 5 birds each) and fed corn and soybean meal-based diets containing 0.28%, 0.35%, 0.43%, 0.50%, and 0.58% Met, respectively, for 4 weeks. Met-deficient (Met-D, 0.28% Met) and Met-adequate (Met-A, 0.43% Met) groups were selected for subsequent molecular studies. Serum, liver, and abdominal fat samples were collected to assess the genes and proteins involved in lipid metabolism of Pekin ducks and hepatocytes were cultured in vivo for verification. Results Dietary Met deficiency caused growth depression and excess fat deposition that were ameliorated by feeding diets with adequate Met. Serum triglyceride and non-esterified fatty acid concentrations increased (P < 0.05), whereas serum concentrations of total cholesterol, low density lipoprotein cholesterol, total protein, and albumin decreased (P < 0.05) in Met-D ducks compared to those in Met-A ducks. Based on hepatic proteomics analyses, dietary Met deficiency suppressed expression of key proteins related to fatty acid transport, fatty acid oxidation, tricarboxylic acid cycle, glycolysis/gluconeogenesis, ketogenesis, and electron transport chain; selected key proteins had similar expression patterns verified by qRT-PCR and Western blotting, which indicated these processes were likely impaired. In vitro verification with hepatocyte models confirmed albumin expression was diminished by Met deficiency. Additionally, in abdominal fat, dietary Met deficiency increased adipocyte diameter and area (P < 0.05), and down-regulated (P < 0.05) of lipolytic genes and proteins, suggesting Met deficiency may suppress lipolysis in adipocyte. Conclusion Taken together, these data demonstrated that dietary Met deficiency in Pekin ducks resulted in stunted growth and excess fat deposition, which may be related to suppression of fatty acids transportation and hepatic catabolism.

In the late growth stage of commercial Pekin ducks, a significant increase in feed intake and a decline in body weight gain have been observed, leading to impaired feed conversion efficiency. To address this issue, we investigated alterations in production performance, blood biochemical indices, ileum tissue architecture, and microbial community structure in Pekin ducks. The primary objective was to provide robust data supporting the improvement of meat duck production efficiency during the late growth stage (28–42-days-old). Forty 28-day-old Pekin ducks were randomly assigned to 8 replicates, with five ducks per replicate. The rearing period lasted 14 days, with feed and water provided ad libitum. Our findings indicated a significant increase in Pekin duck body and heart weights with advancing age (P < 0.05). Moreover, serum antioxidant enzyme and high-density lipoprotein concentrations significantly increased, whereas triglyceride levels decreased (P < 0.05). Notably, the height of the ileal villi was significantly reduced (P < 0.05). The microbial community structure of the ileum exhibited significant changes as ducks aged, accompanied by a substantial increase in microbial flora diversity, particularly with the formation of more tightly connected microbial network modules. Time-dependent enrichment was observed in microbial gene functions related to energy metabolism pathways. At the genus level, Sphingomonas and Subdoligranulum have emerged as crucial players in microbial differential functional pathways and network formation. These bacteria likely serve as the key driving factors in the dynamic microbial changes that occur in Pekin ducks over time. Overall, our findings suggest a potential decline in the absorption function of the small intestine and fat deposition performance of Pekin ducks during later growth stages, which may be attributed to the maturation and proliferation of the gut microbial community. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of a commercially available Bacillus-based direct fed microbial (DFM, Amnil®, United Animal Health, Sheridan, IN) on Pekin duck performance and welfare. The study consisted of 5 dietary treatments, each consisting of 10 replicate pens and 25 straight-run day-of-hatch ducks/pen. The treatments included a commercial-type basal diet (CON), or the basal diet supplemented with 125 ppm (A-125), or 250 ppm (A-250), or 500 ppm (A-500), or 750 ppm (A-750) DFM. On D 14 and 35 performance was evaluated. Gait scores (GS), footpad lesions (FPL), complete cell blood counts, nitrogen digestibility, and total plasma corticosterone levels (CORT) were measured at D 35. The average daily feed intake (ADFI) and feed conversion ratio (FCR) overall were higher in the CON than all other treatments. Body weights did not differ between treatments. The H/L Ratio and total plasma corticosterone levels for CON were higher than all of treatments. Nitrogen digestibility for CON was lower than all other treatments. Gait Scores and Footpad Lesion Scores did not differ between treatments. Utilization of the DFM at any inclusion rate improved feed efficiency, reduced stress susceptibility, and improved nitrogen digestibility. While gait scores, footpad scores, and body weights were not affected by supplementation, feeding this DFM to Pekin ducks can improve their performance and welfare. [ABSTRACT FROM AUTHOR]

Nest design is one factor contributing to floor-laying in farmed poultry. We investigated: (i) if ducks (Anas platyrhynchos) prefer a particular nest substrate; and (ii) how important that preference is to them, indicated by stress-induced hyperthermia, egg albumen corticosterone, and behaviour. Twelve female ducks that were trained in a push-door task had temperature data loggers implanted. Preference testing identified the most and least preferred nest substrates between sawdust, astroturf, and hemp fibres. A behavioural demand test then required the ducks to use push-doors to access nests containing either the most or least preferred substrate. The preferred substrate door was loaded with increasing weight (0–120% of bodyweight, four nights per workload) and eventually blocked to prevent nest access. The least preferred substrate door remained unweighted. The overall rank order of substrate preferences was sawdust > hemp > astroturf. Six of the 12 birds pushed all workloads and attempted to push the blocked door. The area under the curve (AUC) of hyperthermia was larger when the preferred substrate door was blocked compared with 0%. The AUC did not differ between nights 2–4 of the blocked door compared with night 1. Egg albumen corticosterone was unaffected. We conclude that laying Pekin ducks prefer manipulatable nest substrates and accessing one is important enough to pay a cost. The results indicate that a manipulatable substrate should be provided to commercially farmed nesting ducks.

This study aimed at investigating the effects of dietary Saccharomyces cerevisiae (SC) on the intestinal flora structure and barrier function of Pekin duck. A total of 180 1-day-old Pekin ducks were randomly divided into 3 groups with 6 replicates in each group and 10 birds per replicate. The birds in the control group (CON) were fed the basal diet, and those in the experimental group were fed the basal diets supplemented with 600 mg/kg SC (LSC) and 1,200 mg/kg (HSC), respectively. The trial lasted for 42 d. Results showed that LSC and HSC treatments tended to improve the feed conversion efficiency during the trial. The ileum length of birds in the LSC and HSC groups was elevated. Additionally, with 600mg/kg SC supplemented, the mRNA levels of villin, claudin3, and MUC 2 in d21 were up-regulated, as well as the mRNA levels of villin, claudin3, occludin, i-FABP, ZO-1, and MUC 2 in d42. In addition, dietary SC supplementation improved the α-diversity of the bacteria in cecal chyme and tended to increase the abundance (RA) of Bacteroidetes (P = 0.071). Besides, the RA of Ruminococcaceae_UCG-014 was raised in the LSC group. Beyond that, the RA of Proteobacteria was descended with two levels of SC added. In conclusion, dietary Saccharomyces cerevisiae, particularly at 600 mg/kg level, improved the intestinal flora structure and barrier function of Pekin duck.

Global warming poses detrimental effects on poultry production leading to substantial economic losses. The goal of our experiment was to test the hypothesis that heat stress (HS) would alter welfare and egg quality (EQ) of breeder ducks. Furthermore, we wanted to test if HS would increase cortisol levels in egg albumen. Adult Pekin ducks were randomly assigned to two different rooms at 85% lay with 60 hens and 20 drakes per room. Baseline data including body weight, body condition scores (BCS), and egg production/quality were collected the week preceding heat treatment. Ducks were subjected to cyclic HS of 35°C for 10h/day and 29.5°C for the remaining 14h/day for 3 weeks while the control room was maintained at 22°C. Eggs were collected daily and analyzed weekly for quality assessment, and for albumen glucocorticoid (GCs) levels using mass spectrometry. One week before the exposure to HS, 10 hens and 5 drakes were euthanized and the same number again after 3 weeks and birds necropsied. Data analyses were done by 1- or 2-way ANOVA as appropriate with a Tukey-Kramer post hoc test. BCS were analyzed using a chi-squared test. A p ≤ 0.05 was considered significant. Circulating levels of corticosterone were significantly (p < 0.01) elevated at week 1 only in the HS hens. The circulating levels of cortisol increased significantly at week 1 and 2 (p < 0.05), and week 3 (p < 0.01) in the hens and at weeks 2 and 3 only (p < 0.05) in the drakes. Feather quality scores (p < 0.01), feather cleanliness scores (p < 0.001) and footpad quality scores (p < 0.05) increased significantly in the HS group. HS elicited a significant (p < 0.001) decrease in egg production at weeks 1 and 3. Hens in the HS group showed significantly decreased BW (p < 0.001) and number of follicles (p < 0.05). Shell weight decreased significantly at week 1 only (p < 0.05) compared to controls. Yolk weight decreased significantly at week 3 (p < 0.01) compared to controls. HS elicited a significant increase in albumen cortisol levels at week 1 (p < 0.05) and week 3 (p < 0.05). Thus, cortisol may provide critical information to further understand and to improve welfare. [ABSTRACT FROM AUTHOR]

Simple Summary: Male and female ducklings are typically reared in same-sex groups. With the goal of improving the males' reproductive performance, and overall flock fertility, some flock owners place several female ducklings into the otherwise all-male pens during rearing. However, the relationships between rearing, drake reproductive success, and flock fertility have not been confirmed. To fill these knowledge gaps, we compared the frequencies of correctly oriented mounts and circulating testosterone levels of drakes reared with and without physical access to females, and the impacts of these rearing treatments on flock fertility. Rearing treatment did not impact any of the measured variables; however, all were affected by age. Individual variation in behavior and testosterone measures were noted in both treatment groups. We conclude that rearing male ducklings with auditory and visual, but without physical access to female ducklings is sufficient for promoting reproductive behavior and physiology, and securing high fertility within this Pekin duck breed. Commercially housed Pekin ducks (Anas platyrhynchos) are typically reared in same sex groups to facilitate separate diet provisioning. Several female ducklings are sometimes mixed into the otherwise all-male pens. This practice is thought to increase flock reproductive success. To evaluate this hypothesis, we reared ducklings in alternating same-sex groups (150 hens or 30 drakes/pen; 8 groups/sex) and evaluated the impacts of rearing on drake mounting behavior, testosterone levels, and flock fertility. At 12 days, three females were placed into four of the male duckling pens. At 20–22 weeks of age, adjacent male and female pens were moved into pens within a breeder barn, and combined to form mixed-sex pens. The number of correctly aligned mounts performed by 10 focal drakes per pen was evaluated over 3 days (12 h/day) at 26, 32, and 45 weeks of age. Circulating testosterone concentrations were analyzed from blood plasma samples collected from the focal drakes at 15 (baseline), 22, 28, 34 and 45 weeks of age. Pen-level fertility was determined at 33–34 and 45–46 weeks of age. Mount and testosterone data were analyzed using a Generalized Linear Mixed Model and a Linear Mixed Model in R 4.0.5, with duck in pen as a random effect. A Linear Mixed Model was used to analyze fertility data, with pen as a random effect. None of the measured variables were impacted by rearing treatment, but all varied with flock age. Physical access to female ducklings during rearing did not enhance flock reproductive success. [ABSTRACT FROM AUTHOR]

Bacillus subtilis has been widely used in animal husbandry as a potential alternative to antibiotics due to its excellent bacteriostasis and antioxidant activity. This study aims to investigate the effects of Bacillus subtilis on the protection of ducks from Escherichia coli infection and its mechanism. The four experimental groups include the negative control group, positive control group, antibiotic group and Bacillus subtilis group. Ducks in positive, antibiotic and Bacillus subtilis groups are orally administered with Escherichia coli and equivalent saline solution for the negative group. The results show that supplements with Bacillus subtilis enhances the performance and health status of the infected ducks. Moreover, Bacillus subtilis alleviates the increase in globulin, LPS and MDA, and the decrease in albumin, T-AOC and T-SOD in the serum caused by Escherichia coli infection. Bacillus subtilis also attenuates injury in the intestine and partially reverses the increase in ROS production and the depletion of ATP in the jejunum. These effects are accompanied with the change of related genes of the ribosome (13.54%) and oxidative phosphorylation (6.68%). Collectively, Bacillus subtilis alleviates the damage caused by Escherichia coli infection in ducks by activating ribosome and oxidative phosphorylation signaling to regulate antioxidant and energy metabolism. [ABSTRACT FROM AUTHOR]

A fusogenic virus was isolated from a flock of breeder Pekin ducks in 2019, Hungary. The affected flock experienced a marked decrease in egg production. Histopathological lesions were seen in the oviduct and in the lungs of birds sent for diagnostic investigation. The fusogenic agent was characterized as an orthoreovirus by viral metagenomics. The assembled viral genome was composed of 10 genomic segments and was 23,433 nucleotides (nt) in length. The study strain, designated Reo/HUN/DuckDV/2019, shared low‐to‐medium gene‐wise sequence identity with avian orthoreovirus strains from galliform and anseriform birds (nt, 38.90%–72.33%) as well as with representative strains of neoavian orthoreoviruses (nt, 40.07%–68.23%). On the contrary, the study strain shared 86.48%–95.01% pairwise nt sequence identities with recent German and Chinese reovirus isolates, D2533/6 and Ych, respectively. Phylogenetic analysis clustered all three unusual waterfowl pathogens on a monophyletic branch, indicating a common evolutionary origin of Reo/HUN/DuckDV/2019 with these enigmatic orthoreoviruses described over the past few years. The finding that a candidate new orthoreovirus species, tentatively called Avian orthoreovirus B, was isolated in recent years in Europe and Asia in moribund ducks seems an alarming sign that needs to be better evaluated by extending laboratory diagnosis of viral pathogens in countries where the waterfowl industry is important. [ABSTRACT FROM AUTHOR]

Simple Summary: Lipid deposition in animals is closely related to lipid anabolism. In order to further explore how differences in different metabolic types regulate lipid deposition, we compared the growth performance and lipid droplet metabolism of fatty-type ducks and lean-type ducks. The results showed that fatty-type ducks showed a faster growth rate and more fat deposition in the early growth stage after feeding the same diet, and produced more lipoproteins in serum and deposited in adipose tissue. However, fewer triglycerides accumulated in the liver. We believe that this performance of fatty-type ducks is caused by the increased expression level of lipid droplet-related genes. The reasons for differences in lipid depositions between fatty-type (F-T) and lean-type (L-T) ducks remain unknown. The present study aimed to compare the growth performance, lipid deposition, and gene expression related to lipid droplet formation in F-T and L-T Pekin ducks. One-day-old, 140 each L-T and F-T male ducks were selected and distributed separately into 20 replicate cages. All ducks were fed commercial diets up to 35 d of age. F-T ducks had a higher average daily gain from 21 to 28 d of age. On 35-day-old, F-T ducks had higher serum levels of high- and low-density lipoprotein cholesterol, cholesterol, albumin, and hydroxybutyrate dehydrogenase activity than L-T ducks. F-T ducks had higher abdominal fat and subcutaneous fat percentages than those in L-T ducks. Liver histological examination showed that L-T ducks contained more lipid droplets in the liver, which gradually decreased with increasing age. The average adipocyte area and diameter of abdominal fat and subcutaneous fat in the F-T and L-T ducks increased with age and were higher in F-T ducks than those in L-T ducks. Furthermore, the gene expression of perilipin 1, perilipin 2, angiopoietin-like protein 4, adipose triglyceride lipase, alpha/beta-hydrolase domain-containing protein 5 (ABHD5), and serine/threonine kinase 17a in the liver, abdominal fat, and subcutaneous fat of F-T ducks was higher than that in L-T ducks, and it increased with age. Compared to L-T ducks, F-T ducks had higher expression of ABHD5 in the abdominal fat and subcutaneous fat and lower expression in the liver. Thus, F-T ducks displayed lower hepatic lipid deposition and a higher percentage of abdominal fat and subcutaneous fat, suggesting that F-T ducks had higher lipid storage capacity due to increased gene expression related to lipid droplets. [ABSTRACT FROM AUTHOR]

Colibacillosis is one of the major health threats in the poultry industry worldwide. Understanding the pathogenic mechanisms involved in Escherichia coli-induced inflammatory response may lead to the development of new therapies to combat the disease. To address this, a total of 96 1-day-old male lean Pekin ducklings were employed and randomly allocated to two treatments, each with six replicates of eight ducks. Ducks in the experiment group (EG) and the control group (CG) were separately orally administered with 0.2 ml of pathogenic E. coli O88 (3 × 109 CFU/ml) or equivalent volumes of 0.9% sterile saline solution on day 7, two times with an 8-h interval. Serum and intestinal samples were collected on days 9, 14, and 28. Results showed that ducks challenged with E. coli had lower average daily gain and higher feed intake/weight gain during days 9-14 and overall (P < 0.05). Histopathological examination showed that E. coli decreased the villus height and the ratio of villus height/crypt depth in the jejunum (P < 0.05) on days 9 and 14. The intestinal barrier was disrupted, presenting in E. coli ducks having higher serum DAO and D-LA on days 9 and 14 (P < 0.05) and greater content of serum LPS on day 9 (P < 0.05). Escherichia coli infection also triggered a systemic inflammatory response including the decrease of the serum IgA, IgM, and jejunal sIgA on day 14 (P < 0.05). In addition to these, 1,062 differentially expressed genes were detected in the jejunum tissues of ducks by RNA-seq, consisting of 491 upregulated and 571 downregulated genes. Based on the KEGG database, oxidative phosphorylation and the ribosome pathway were the most enriched. These findings reveal the candidate pathways and genes that may be involved in E. coli infection, allow a better understanding of the molecular mechanisms of inflammation progression and may facilitate the genetic improvement of ducks, and provide further insights to tackle the drug sensitivity and animal welfare issues. [ABSTRACT FROM AUTHOR]

Objective According to market demand, meat duck breeding mainly includes 2 breeding directions: lean Pekin duck (LPD) and fat Pekin duck (FPD). The aim of the present study was to compare carcass and meat quality traits between 2 strains, and to provide basic data for guidelines of processing and meat quality improvement. Methods A total of 62 female Pekin ducks (32 LPDs and 30 FPDs) were slaughtered at the age of 42 days. The live body weight and carcass traits were measured and calculated. Physical properties of breast muscle were determined by texture analyzer and muscle fibers were measured by paraffin sections. The content of inosine monophosphate (IMP), intramuscular fat (IMF) and fatty acids composition were measured by high-performance liquid chromatography, Soxhlet extraction method and automated gas chromatography respectively. Results The results showed that the bodyweight of LPDs was higher than that of FPDs. FPDs were significantly higher than LPDs in subcutaneous fat thickness, subcutaneous fat weight, subcutaneous fat percentage, abdominal fat percentage and abdominal fat shear force (p0.05). The polyunsaturated fatty acid content of LPDs was significantly higher than that of FPDs (p

ABSTRACT: Lactobacillus plantarum (LP) contributes to the intestinal health, whereas the study about the effects of LP on Pekin ducks is lacking. This study aimed to investigate the effects of LP on growth performance and intestinal health of Pekin ducks. A total of 180 one-day-old birds were randomly allotted to 3 treatments, and ducks were fed with a basal diet (Control) or basal diet supplemented with 400 (LP1) and 800 (LP2) mg/kg LP (5 × 109 CFU/g). The animal trial lasted for 42 d. Results showed that the LP1 and LP2 treatments improved growth performance (feed conversion) of ducks during the period of 1 to 42 d. At the end of 21 d, the decreased serum levels of interleukin (IL)-1β, interferon (IFN)-γ as well as downregulated ileal mRNA expression of IL-1β were observed in 2 doses of LP group. Meanwhile, the ileal mRNA levels of major histocompatibility complex (MHC)-II, IL-4, Claudin, Occludin were upregulated with 2 doses of LP supplemented. In addition, both LP treatments increased the relative abundance of Firmicutes and decreased Bacteroidetes wherein the relative abundance of Bacteroides fragilis was dropped parallelly. It is worth mentioning that markedly increased secretory immunoglobulin A content in ileal mucosa was observed in the LP1 group at d 21. At the end of the trial, the levels of serum complement 3 and β-defense were elevated with 2 doses of LP treated. Additionally, the ileal mRNA expressions of MHC-II, lysozyme were upregulated, and the diversity of the flora was also improved in the LP1 and LP2 groups. In conclusion, dietary LP improved the growth performance and intestinal health of Pekin ducks, and 400 mg/kg LP seemed to work better.

Abstract Background Feeding behavior traits are an essential part of livestock production. However, the genetic base of feeding behavior traits remains unclear in Pekin ducks. This study aimed to determine novel loci related to feeding behavior in Pekin ducks. Results In this study, the feeding information of 540 Pekin ducks was recorded, and individual genotype was evaluated using genotyping-by-sequencing methods. Genome-wide association analysis (GWAS) was conducted for feeding behavior traits. Overall, thirty significant (P-value