Duck Breeds Research Articles

Lack of Serological and Molecular Evidence of Duck Tembusu Virus Infection in Ducks from South Korea

The duck Tembusu virus (DTMUV), an emerging flavivirus, has led to severe neurological disorders and substantial economic losses in the duck industry throughout Asia. Considering South Korea’s increasing duck production and its strategic location along the East Asian–Australasian Flyway, this study aimed to assess the presence of DTMUV in South Korea to evaluate potential risks to the poultry industry. We performed a comprehensive serological survey of 1796 serum samples from broiler and breeder ducks collected between 2011 and 2023, alongside molecular detection tests on 51 duck flocks exhibiting suspected clinical signs of DTMUV infection. The absence of serological and molecular evidence for DTMUV or other flavivirus infections suggests that these viruses have not yet affected South Korean duck populations. These findings underscore the critical need for ongoing surveillance, given the virus’s potential to disrupt agriculture and pose public health risks. The study also emphasizes the importance of maintaining stringent biosecurity measures and conducting further research to monitor and prevent DTMUV transmission, particularly due to the possible role of migratory birds and other vectors in spreading zoonotic diseases.

Novel goose parvovirus in naturally infected ducks suffering from locomotor disorders: Molecular Detection, Histopathological examination, Immunohistochemical signals, and Full genome sequencing

In this study, we investigated the pathological effect of novel goose parvovirus (NGPV) infection on the skeletal muscle, brain, and intestine of naturally affected ducks suffering from locomotor dysfunction as a new approach for deeper understanding of such clinical form. For this purpose, a total of 97 diseased ducks, representing 24 flocks of different duck breeds (14-75 days old), were clinically examined. 72 tissue pools of intestine, brain, and skeletal muscle samples were submitted for molecular identification. Typical clinical signs among the examined ducks suggested the parvovirus infection. Regarding postmortem examination, all examined ducks showed muscle emaciation (100%) either accompanied by congestion (34%) or paleness (66%). Slight congestion, either in the brain (82.5%) or intestine (75.25%), was predominantly detected. Based on molecular identification, the intestine had the highest percentage of positive detection (91.7%), followed by the skeletal muscle (70.8%), and the brain (20.8%). The main histopathological alterations were myofiber atrophy and degeneration, marked enteritis accompanied by lymphocytic infiltration in the lamina propria and submucosa, while the affected brains showed vasculitis, diffuse gliosis, and Purkinje cell degeneration in the cerebellum. Next generation sequencing further confirmed the presence of a variant strain of goose parvovirus (vGPV) that is globally known as NGPV and closely related to Chinese NGPV isolates. Using immunohistochemistry, the NGPV antigen was positively detected in the muscle fibres, enterocytes, and Purkinje cells in the cerebellum. These findings provided proof of the involvement of virus replication in the locomotor disorders linked to NGPV infection in ducks.

Transcriptional activity and variation analysis of genes critical for long-chain fatty acid (C≥16) elongation and desaturation in Pekin ducks

To deepen our understanding of long-chain fatty acid carbon chain elongation and desaturation in ducks, this study systematically analyzed the transcriptional activities of key gene promoters, including ELOVLs, FADSs, and SCDs. Predictive modeling coupled with statistical analysis revealed a prevalence of binding motifs for transcription factors, particularly those associated with Sp1, NF-1, and C/EBPalpha. Moreover, variation analysis of resequencing data from both wild and domestic ducks, specifically mallards and Pekin ducks, informed targeted mutagenesis within the core promoter regions of ELOVL2, ELOVL5, and ELOVL6. Notably, mutations at positions -56 G>C in ELOVL2, -52 T>C in ELOVL5, and -513 T>C in ELOVL6 significantly diminished transcriptional activity. These findings substantially enhance our understanding of the molecular mechanisms regulating the biosynthesis of long-chain fatty acids in ducks and support future genetic selection initiatives aimed at developing Pekin duck breeds with enhanced nutritional value.

Comparative pathogenicity of duck hepatitis A virus genotype 3 in different duck breeds: Implications of the diagnosis and prevention of duck viral hepatitis

Duck hepatitis A virus (DHAV) infection in ducklings causes acute hepatitis with considerable economic losses. In this study, Pekin and Muscovy duckling flocks (n=9) suffering from high mortality and hepatic lesions were examined by RT-PCR for DVHA. 44.4 % (4/9) of samples were positive for DHAV (5′ UTR region), of which 100 % (4/4) were DVHA-3 (VP1 gene). VP1 sequencing and phylogenetic analysis of an isolate originated from Muscovy ducklings showed that it shared 96.8 % −100 %, 88.5–89.2 %, and 86.5–88.2 % nucleotide similarity (ns) with the Egyptian, Korean-Vietnamese, and Chinese DVHA-3 strains, respectively. It was distinguished from the DHAV-1 vaccine (67.6 % ns). The sequenced DVHA-3 isolate was used to experimentally infect 5-day-old Pekin and Muscovy ducklings vs. control groups. No apparent clinical signs or deaths were reported in the experimentally-infected groups. Pekin ducklings showed greater cloacal viral shedding than Muscovy until the 6th dpi (P<0.05). DVHA-3 induced a significant rise in IFN-β and IL-1β serum levels, where Muscovy ducklings' levels were higher than Pekin ducklings. Among the biochemical parameters, AST was only increased on the 4th dpi in both breeds vs. control (P<0.05). Compared to Muscovy ducklings at 2, 4, and 6 day post infection (dpi), the infected Pekin group had lower lipase levels (P≥0.05, p<0.05, and p<0.05, respectively), while ALT was higher at 4 and 6 dpi (P<0.05). The histopathological lesions supported the gross lesions, and their scores were dominant at 2 and 4 dpi in both breeds. At 6 and 8 dpi, Pekin showed more severe histopathological changes compared to Muscovy for the liver, heart, brain, and intestines; the pancreas, kidney, and lung showed the opposite pattern. In conclusion, Pekin ducklings displayed distinct DHAV-3 infection results from Muscovy ducklings, and more research utilizing a variety of DHAV-3 strains has to be carried out.

Duck circovirus regulates the expression of duck CLDN2 protein by activating the MAPK-ERK pathway to affect its adhesion and infection.

Although duck circovirus (DuCV) poses a widespread infection and a serious hazard to the duck industry, the molecular mechanisms underlying DuCV infection and transmission remain elusive. We initially demonstrated vertical transmission of DuCV through female breeding ducks by simulating natural infection. Furthermore, a differentially expressed membrane protein CLDN2 was identified on the DuCV-infected oviduct of female ducks, and its extracellular loop structural domains EL1 and EL2 were identified as the interaction sites of DuCV Cap proteins. Moreover, the binding of DuCV Cap to CLDN2 triggered the intracellular MAPK-ERK pathway and activated the downstream transcription factor SP5. Importantly, we demonstrated that intracellular Cap also interacts with SP5, leading to upregulation of CLDN2 transcription and facilitating enhanced adherence of DuCV to target tissue, thereby promoting viral infection and transmission. Our study sheds light on the molecular mechanisms underlying vertical transmission of DuCV, highlighting CLDN2 as a promising target for drug development against DuCV infection.

Comparative analysis of reproductive hormones, serum biochemical indexes and ovarian metabolites in Muscovy breeder duck at different laying stages

The hypothalamic-pituitary-gonadal (HPG) axis regulates egg laying through control hormones secretion in poultry. In this study, the serum hormones (12 samples per stage), serum biochemical indexes (12 samples per stage), and ovarian metabolites (8 samples per stage) of Muscovy breeder ducks were detected at prelaying stage (PT), start of laying stage (ST), high laying stage (HT), and the end of laying stage (ET). The serum hormones of Muscovy ducks were measured at 8:00, 13:00, 18:00, 23:00, and 4:00 within 1 d. The TG, TP, ALB, and GLB were significantly increased, while HDL-C was significantly decreased at ST as compared to PT (P < 0.05). Serum Na, Cl, Ca, P, and K showed significant rise at ST as compared to PT. Serum Na, Cl, Ca, and K were significantly declined, while P was significantly increased at ET as compared to HT (P < 0.05). Serum FSH, LH, PRL, E2, P4 levels peaked at ST (P < 0.05) with only FSH and LH fluctuated significantly within 1 ovulation cycle at ST (P < 0.05). Differential metabolites showed continued ovarian aging. The decline of nucleic acid metabolism occured in ST, the decline of sugar metabolism occurred in ET, and the decline of amino acid metabolism continued at all stages. Temporal expression patterns and correlation analyses indicated a high correlation between ovarian cAMP and serum reproductive hormone levels across different reproductive stages. In conclusion, this study revealed the changes in serum hormones, serum biochemical indicators, and ovarian metabolites, as well as the relationship between serum hormones and ovarian metabolites.

Nutritional Impacts of Dietary Selenium, Iodine and their Interaction on Egg Performance, and Antioxidant Profile in Laying Longyuan Duck Breeders.

The present study aimed to optimize the combined effect of dietary selenium (SE) and iodine (ID) on the productive and reproductive performance and antioxidant capacity of Longyuan breeding ducks. A total of 288 Longyan duck breeders aged 20 wk were randomly assigned to four groups with six replicates (n = 72 ducks/group; 12 ducks/replicate). A 2 × 2 factorial arrangement experiment was performed and included 2 supplementation levels of each SE and ID for 200 days of the experimental period. The first group (SE0/ID0) received a basal diet without SE or ID supplementation and was considered to be the control group, whereas the other three groups, SE0/ID4, SE2/ID0 and SE2/ID4, received a basal diet supplemented with 0.4 mg ID/kg, 0.2 mg SE/kg or 0.2 mg SE supplemented with 0.4 mg ID/kg, respectively. The results indicated that the albumin height of the SE2/ID0 group was lower (P < 0.05) than that of the control group, that the egg shape index of the SE2/ID4 and SE0/ID4 groups were lower (P < 0.05) than that of the control group (SE0/ID0), and that the SE concentration significantly increased (P < 0.05) in the SE2/ID0 and SE2/ID4 groups. Hatchability and embryonic mortality improved (P < 0.05) in the SE2/ID0 group. Plasma GSH-Px activity was increased (P < 0.05) by reducing the concentration of malondialdehyde (MDA) in the SE groups. In addition, the tibia length significantly increased (P < 0.05) in the ID (SE0/ID4 and SE2/ID4) groups compared with that in the control group, the plasma content of IGF-1 in the SE2/ID4 and SE0/ID4 groups were greater (P < 0.05) than that in the control group, and the bone mineral content increased (P > 0.05) in the SE2/ID0 and SE0/ID0 groups. Compared with those in the other groups, the mRNA expression of antioxidant-related genes, including Nrf2 and SHMT1 in the SE2/ID4 group was upregulated (P > 0.05), especially in the SE2/ID4 group. Overall, dietary treatment with SE2/ID4 (0.2 mg SE in 0.4 mg ID/kg diet) could be a suitable feed supplement for improving the the egg quality, health status, endogenous antioxidant content, antioxidant-related gene expression and pre-hatching quality of Longyuan duck breeders.

Genome-Wide Association Analysis Identifies Important Haplotypes and Candidate Gene XKR4 for Body Size Traits in Pekin Ducks.

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.

Polymorphisms in the Growth Hormone Gene and Their Association with Pre-pullet Body Weight in Kuttanad Ducks of Kerala, India

Background: Kuttanad ducks are dual purpose native ducks found in Kerala state of India. Identification of single nucleotide variations in candidate genes like growth hormone gene and exploring their association with body weight at grower and pre-pullet stages is essential for the marker assisted selection of breeder ducks for genetic improvement. Methods: Genomic DNA was extracted from blood samples collected from 101 Kuttanad ducks. PCR-amplification of two duck growth hormone gene (dGH) loci viz, exon 3 and partial intron 3 (227 bp), exon 5 and partial intron 4 (366 bp) were undertaken using custom-synthesised primers. The 366 bp region was genotyped using Single Strand Conformation Polymorphism. The 227 bp region was genotyped using DNA pooling assay to yield a 139 bp product for subsequent High-Resolution Melting analysis. The association of dGH genotypic variants for these loci with fortnightly body weight at pre-pullet stages up to 16 weeks of age was analysed. Result: In the 366 bp fragment, GG and GA genotypes were revealed with one novel SNP (g 74G greater than A). The GG homozygotes had significantly higher body weight at all stages from two to 14 weeks of age (p≤0.01). A novel SNP (g 71A greater than G) was revealed at the 139 bp locus within the 227 bp region with three genotypes viz., AA, AG and GG. The GG homozygotes had significantly higher body weight at six, 14 and 16 weeks of age (p≤0.05). The study revealed that dGH polymorphic loci have jointly contributed to the variation in growth and hence can be used as markers for the primary selection of growers at sixth week of age followed by their secondary selection at 14-16 weeks of age during the multi-stage selection programmes for breeder ducks.

Peningkatan Hardskill Ibu Rumah Tangga Sebagai Upaya Meningkatkan Penghasilan Keluarga Melalui Pelatihan Pembuatan Telur Asin Di Desa Bajo Kecamatan Soromandi

Counseling on "increasing the hard skills of housewives as an effort to increase family income through training in making salted eggs in Bajo Village, Soromandi District" was carried out in August by involving various community groups including duck breeders, Soromandi Village officials, and the community around the service location. This activity was carried out through counseling and discussion as well as short training through demonstration and practice on salted egg making. This extension involved more than 37 participants from the planned 20 participants and also involved 3 students who were in their final semester. The results of the extension showed that the extension participants were very enthusiastic about this training meter can be seen from active participation in all activities, especially during discussion and practice sessions and increased understanding of salted egg making in an effort to increase the added value of duck eggs produced including to increase egg storage time so that it can be consumed in a relatively longer period of time than ordinary consumption eggs and increase the selling value of eggs. Keywords: Eggs, salted eggs, dedication, Bajo Village

Testing the form-function paradigm: body shape correlates with kinematics but not energetics in selectively-bred birds

A central concept of evolutionary biology, supported by broad scale allometric analyses, asserts that changing morphology should induce downstream changes in locomotor kinematics and energetics, and by inference selective fitness. However, if these mechanistic relationships exist at local intraspecific scales, where they could provide substrate for fundamental microevolutionary processes, is unknown. Here, analyses of selectively-bred duck breeds demonstrate that distinct body shapes incur kinematic shifts during walking, but these do not translate into differences in energetics. A combination of modular relationships between anatomical regions, and a trade-off between limb flexion and trunk pitching, are shown to homogenise potential functional differences between the breeds, accounting for this discrepancy between form and function. This complex interplay between morphology, motion and physiology indicates that understanding evolutionary links between the avian body plan and locomotor diversity requires studying locomotion as an integrated whole and not key anatomical innovations in isolation.

Integrated omics analysis reveals the differentiation of intestinal microbiota and metabolites between Pekin ducks and Shaoxing ducks

Pekin ducks and Shaoxing ducks are 2 Chinese local duck breeds, both domesticated from mallard, but after domestication and long-term artificial selection, the body weight of Pekin ducks is significantly higher than that of Shaoxing ducks. It is no debate that genetic factors are the main factors responsible for this difference, but whether intestinal microbiota contribute to this difference is yet unknown. Thus, we performed comparative intestinal metagenomics and metabolomics analysis between Pekin ducks and Shaoxing ducks. We found obvious differentiation of intestinal metagenome and metabolome between the 2 breeds. Four cecal microbial genera, including Fusobacterium, Methanobrevibacter, Butyricicoccus, and Anaerotignum showed higher abundance in Pekin ducks. Among them, Methanobrevibacter and Butyricicoccus may positively correlate with fat deposition and body weight. A total of 310 metabolites showed difference between the 2 breeds. Functions of these differential metabolites were mainly enriched in amino acid metabolism, including energy metabolism-related histidine metabolism. Integrated omics analysis showed that microbial changes were closely related to altered metabolites. Especially, Butyricicoccus showing higher abundance in Pekin ducks was significantly negatively correlated with D-glucosamine-6-phosphate, which has been reported to prevent body weight gains. These findings may contribute to further understand the difference in body weight between Pekin ducks and Shaoxing ducks.

Phenotypic Identification, Genetic Characterization, and Selective Signal Detection of Huitang Duck.

The Huitang duck (HT), a long-domesticated elite local breed from Hunan Province, China, with excellent meat quality, has not had its population genetic structure and genomic selective sweeps extensively studied to date. This study measured the phenotypic characteristics of HT and conducted comparative analysis between HT and 16 different duck breeds, including wild, indigenous, and meat breeds, to characterize its population structure and genetic potential. The results revealed that HT is a dual-purpose indigenous breed with a genetic background closely related to the Youxian sheldrake and Linwu ducks. In the selective sweep analysis between HT and Linwu ducks, genes such as PLCG2, FN1, and IGF2BP2, which are associated with muscle growth and development, were identified near the 27 selection signals. The comparison between HT and Jinding ducks revealed 68 selective signals that contained important genes associated with ovarian development (GRIK4, MAP3K8, and TGIF1) and egg-laying behaviors (ERBB4). Selective sweep analysis between HT and Youxian sheldrake ducks found 93 selective regions covering genes related to both meat (IGF1R and IGFBP5) and egg-production (FOXO3 and ITPR1) traits. Our study may provide novel knowledge for exploring the population structure and genetic potential of HT, offering a theoretical basis for its breeding strategies in the future.

Riding the wetland wave: Can ducks locate macroinvertebrate resources across the breeding season?

Food availability varies considerably over space and time in wetland systems, and consumers must be able to track those changes during energetically-demanding points in the life cycle like breeding. Resource tracking has been studied frequently among herbivores, but receives less attention among consumers of macroinvertebrates. We evaluated the change in resource availability across habitat types and time and the simultaneous density of waterfowl consumers throughout their breeding season in a high-elevation, flood-irrigated system. We also assessed whether the macroinvertebrate resource density better predicted waterfowl density across habitats, compared to consistency (i.e., temporal evenness) of the invertebrate resource or taxonomic richness. Resource density varied marginally across wetland types but was highest in basin wetlands (i.e., ponds) and peaked early in the breeding season, whereas it remained relatively low and stable in other wetland habitats. Breeding duck density was positively related to resource density, more so than temporal resource stability, for all species. Resource density was negatively related to duckling density, however. These results have the potential to not only elucidate mechanisms of habitat selection among breeding ducks in flood-irrigated landscapes but also suggest there is not a consequential trade-off to selecting wetland sites based on energy density versus temporal resource stability and that good-quality wetland sites provide both.

Whole-genome selection signature differences between Chaohu and Ji'an red ducks.

Assessing the genetic structure of local varieties and understanding their genetic data are crucial for effective management and preservation. However, the genetic differences among local breeds require further explanation. To enhance our understanding of their population structure and genetic diversity, we conducted a genome-wide comparative study of Chaohu and Ji'an Red ducks using genome sequence and restriction site-associated DNA sequencing technology. Our analysis revealed a distinct genetic distinction between the two breeds, leading to divided groups. The phylogenetic tree for Chaohu duck displayed two branches, potentially indicating minimal impact from artificial selection. Additionally, our ROH (runs of homozygosity) analysis revealed that Chaohu ducks had a lower average inbreeding coefficient than Ji'an Red ducks. We identified several genomic regions with high genetic similarity in these indigenous duck breeds. By conducting a selective sweep analysis, we identified 574 candidate genes associated with muscle growth (BMP2, ITGA8, MYLK, and PTCH1), fat deposits (ELOVL1 and HACD2), and pigmentation (ASIP and LOC101797494). These results offer valuable insights for the further enhancement and conservation of Chinese indigenous duck breeds.

A comparative analysis reveals the genomic diversity among 8 Muscovy duck populations.

The Muscovy duck (Cairina moschata) is a waterfowl indigenous to the neotropical regions of Central and South America. It has low demand for concentrated feed and strong adaptability to different rearing conditions. After introduced to China through Eurasian commercial trade, Muscovy ducks have a domestication history of around 300 years in the Fujian Province of China. In the 1990s, the commodity Muscovy duck breed "Crimo," cultivated in Europe, entered the Chinese market for consumption and breeding purposes. Due to the different selective breeding processes, Muscovy ducks have various populational traits and lack transparency of their genetic background. To remove this burden in the Muscovy duck breeding process, we analyzed genomic data from 8 populations totaling 83 individuals. We identify 11.24 million single nucleotide polymorphisms (SNPs) and categorized these individuals into the Fujian-bred and the Crimo populations according to phylogenetic analyses. We then delved deeper into their evolutionary relationships through assessing population structure, calculating fixation index (FST) values, and measuring genetic distances. Our exploration of runs of homozygosity (ROHs) and homozygous-by-descent (HBD) uncovered genomic regions enriched for genes implicated in fatty acid metabolism, development, and immunity pathways. Selective sweep analyses further indicated strong selective pressures exerted on genes including TECR, STAT2, and TRAF5. These findings provide insights into genetic variations of Muscovy ducks, thus offering valuable information regarding genetic diversity, population conservation, and genome associated with the breeding of Muscovy ducks.

Analysis of the Cost Efficiency of Using Feed with Different Types of Feed and Ducks

This study examined how cost-effective it was to raise three distinct kinds of ducks using three different types of feed. The results of this study should help researchers and the general public, particularly breeders, by supplying information on the kinds of feed and duck varieties that are more cost-effective in duck farming. Three distinct types of feed and three distinct breeds of ducks were used in this investigation. The study used an experimental design with a factorial pattern (3 x 3) and a completely randomized design (CRD), with three replications made up of two components with the codes factor A and factor B. A1 (feed BR1), A2 (feed PP3), and A3 (feed mix) make up factor A, which is the type of feed. Duck types comprise factor B, which includes B1 (Peking duck), B2 (Mojosari duck), and B3 (MA duck). The factors that were observed were feed cost per gain (FCG), economic efficiency of ration usage (EEPP), and efficient use of rations (FE). The acquired data were subjected to variance analysis (ANOVA), and the Duncan multiple range test (DMRT) was used to determine how the treatments differed. The study indicated that variables A and B did not interact in treatments. Regarding the cost-effectiveness of using feed, factor A had a highly significant effect (P &gt; 0.01). However, factor B had no discernible impact. This study concludes that the PP3 type of ration, which uses the more efficient Peking duck, has the best cost-efficiency when using rations. Based on the study findings, the recommendation is to employ Peking ducks fed PP3 diets to raise broiler ducks to their maximum body weight while minimizing ration expenses.

Duck gut metagenome reveals the microbiome signatures linked to intestinal regional, temporal development, and rearing condition.

The duck gastrointestinal tract (GIT) harbors an abundance of microorganisms that play an important role in duck health and production. Here, we constructed the first relatively comprehensive duck gut microbial gene catalog (24 million genes) and 4437 metagenome-assembled genomes using 375 GIT metagenomic samples from four different duck breeds across five intestinal segments under two distinct rearing conditions. We further characterized the intestinal region-specific microbial taxonomy and their assigned functions, as well as the temporal development and maturation of the duck gut microbiome. Our metagenomic analysis revealed the similarity within the microbiota of the foregut and hindgut compartments, but distinctive taxonomic and functional differences between distinct intestinal segments. In addition, we found a significant shift in the microbiota composition of newly hatched ducks (3 days), followed by increased diversity and enhanced stability across growth stages (14, 42, and 70 days), indicating that the intestinal microbiota develops into a relatively mature and stable community as the host duck matures. Comparing the impact of different rearing conditions (with and without water) on duck cecal microbiota communities and functions, we found that the bacterial capacity for lipopolysaccharide biosynthesis was significantly increased in ducks that had free access to water, leading to the accumulation of pathogenic bacteria and antibiotic-resistance genes. Taken together, our findings expand the understanding of the microbiome signatures linked to intestinal regional, temporal development, and rearing conditions in ducks, which highlight the significant impact of microbiota on poultry health and production.

Trans-Atlantic introduction of the Anas Mallard duck (Anas Platyrhynchos) into Nigeria following mtDNA footprints

Apart from the Nigerian indigenous Muscovy duck breed, which is endemic in the country, the Anas mallard is found in fairly abundant numbers, especially in the Northern part of the country. Although the mallard duck is widely perceived to be of exotic extraction, there is a dearth of information about its origin or how they got introduced into the country, leaving the subject to speculation. Hence this study was carried to trace the evolutionary ancestry of the mallard in Nigeria using the maternally inherited mitochondrial DNA marker. 603bp region of the mtDNA was analyzed following standard extraction and amplification, with specific primers. 20 Nigerian duck sequences in addition to 20 sequences harvested from Genbank representing major native regions of the Anas platyrhynchos, were used to reconstruct phylogenetic trees and matrices. The results revealed a strong genetic relationship between the Nigerian and Western European, particularly British ducks, and a weak lineage with ducks of Egyptian, Asian and Australasian extraction. The study reveals that the Nigerian mallard ducks are evolutionary descendants of the British mallard, whose ancestors would have been introduced into the country following the North-South trans-Atlantic maritime routes during the colonial era. The study did not find any evidence of a trans-Saharan introduction of the mallard into Nigeria from Asia via Egypt. Findings from this research sheds further light on the global dispersion of the duck from its original evolutionary epicenter in South-East Asia, and may be used for designing breeding programs.

Short beak and dwarfism syndrome among Pekin ducks: First detection, full genome sequencing, and immunohistochemical signals of novel goose parvovirus in tongue tissue.

Novel goose parvovirus (NGPV) is continuously threatening the global duck industry, as it causes short beak and dwarfism syndrome among different duck breeds. In this study, we investigated the viral pathogenesis in the tongue of affected ducks, as a new approach for deeper understanding of the syndrome. Seventy-three, 14- to 60-day-old commercial Pekin ducks were clinically examined. Thirty tissue pools of intestine and tongue (15 per tissue) were submitted for molecular identification. Clinical signs in the examined ducks were suggestive of parvovirus infection. All examined ducks had short beaks. Necrotic, swollen, and congested protruding tongues were recorded in adult ducks (37/73, 51%). Tongue protrusion without any marked congestion or swelling was observed in 20-day-old ducklings (13/73, 18%), and no tongue protrusion was observed in 15-day-old ducklings (23/73, 32%). Microscopically, the protruding tongues of adult ducks showed necrosis of the superficial epithelial layer with vacuolar degeneration. Glossitis was present in the nonprotruding tongues of young ducks, which was characterized by multifocal lymphoplasmacytic aggregates and edema in the propria submucosa. Immunohistochemical examination displayed parvovirus immunolabeling, mainly in the tongue propria submucosa. Based on polymerase chain reaction, goose parvovirus was detected in 9 out of 15 tongue sample pools (60%). Next-generation sequencing confirmed the presence of a variant goose parvovirus that is globally named NGPV and closely related to Chinese NGPV isolates. Novel insights are being gained from the study of NGPV pathogenesis in the tongue based on molecular and immunohistochemical identification.