25-Hydroxyvitamin D3 (25(OH)D3) has been reported to improve production performance and egg quality in ducks during the late laying period, but its effects during the peak laying period remain rarely studied. The aim of this study was to investigate the effects of dietary 25(OH)D3 supplementation on the production performance, egg quality, tibia quality, and mineral metabolism of ducks during the peak laying period in a cage rearing system. A total of 360 Liancheng white laying ducks at 30 weeks (wk) of age were randomly assigned to 5 groups, each consisting of 6 replicates with 12 ducks per replicate. Ducks were fed a basal diet with 25(OH)D3 supplementation at 0, 1,000, 2,000, 3,000, and 4,000 IU/kg throughout the trial for 8 wk. One-way ANOVA was employed to assess the influence of supplementation level, and linear and quadratic regression analyses were performed for statistical evaluation of dose-dependent effects. 25(OH)D3 supplementation linearly and quadratically increased the laying rate, average egg weight, and egg mass and quadratically decreased the feed conversion ratio (FCR). The mean of eggshell strength and thickness at 4 and 8 wk increased linearly and quadratically with increasing 25(OH)D3 levels, and the 4000 IU/kg 25(OH)D3 increasing the eggshell thickness by 5.7% (at 4 wk) and 2.9% (mean of those at 4 and 8 wk) relative to those of the non-supplemented group. At the end of weeks 4 and 8 of the trial, serum 25(OH)D3, bone glutamyl protein (BGP), and carbonic anhydrase (CA) increased linearly (P < 0.05), and serum parathyroid hormone (PTH) decreased linearly (P < 0.05); the 4000 IU/kg group had the highest serum 25(OH)D3 (4.24 ng/mL) and BGP (3.11 ng/mL) concentrations at 8 wk. Additionally, the tibial breaking strength, trabecular bone number, BGP content, alkaline phosphatase (ALP) activity, and mRNA levels increased linearly with 25(OH)D3 supplementation (P < 0.05). The optimal dietary 25(OH)D3 supplementation levels were approximately 2,355, 2,347 and 3,269 IU/kg on the basis of the quadratic model of the laying rate, FCR and eggshell strength, respectively. In summary, 25(OH)D3 supplementation improved the production performance and eggshell quality of ducks during the peak laying period by maintaining calcium and phosphorus homeostasis and enhancing tibia quality. A diet that contains 2,347-3,269 IU/kg of 25(OH)D3 displayed beneficial effects on maintaining calcium and phosphorus homeostasis and improving the tibial quality, which was recommended for ducks during peak laying period in the cage rearing system (30-38 wk of age).

Liancheng white ducks have a distinctive "white feathers, black beak, and green feet" phenotype, making them a useful model for studying pigmentation traits in waterfowl. The previous study found that the F1 generation of Liancheng white ducks crossed with white-feathered ducks and hemp-feathered ducks were all gray-black in color. This indicates the specificity and complexity of melanin deposition in Liancheng white ducks, which makes the selection and breeding of pigment traits through phenotyping difficult. The aim of this study was to investigate the candidate transcriptomic regulatory signals of melanogenesis in Liancheng white ducks. Skin, mouth skin, foot skin, liver, and muscle samples were collected from 130-day-old Liancheng white ducks. Morphological differences were observed via histological analysis, and extraction-based pigment levels were determined. The results showed that melanin granules were clearly observed in tissues other than the liver and were distributed mainly in the basal layer of the epidermis and around feather follicles; the pigment values in the tissues decreased in the order mouth skin > liver > foot skin > muscle and skin. However, the relatively high liver value should be interpreted cautiously because obvious melanin granule deposition was not observed histologically. Whole-transcriptome sequencing was performed on mouth skin and skin samples. In total, 3074 differentially expressed genes (DEGs) were screened; upregulated genes associated with melanogenesis included melanocyte inducing transcription factor (MITF) and tyrosinase (TYR); downregulated genes included agouti signaling protein (ASIP) and adenylate cyclase 2 (ADCY2). Eighteen differentially expressed microRNAs (DEmiRNAs) were identified. Based on target prediction and pathway enrichment analysis, novel_290 and apl-miR-11588-3p were identified as candidate miRNAs potentially associated with melanogenesis-related pathways, and their predicted target genes included phosphatidylinositol 3-kinase (PI3K) and Janus kinase 1 (JAK1). Additionally, 364 differentially expressed long noncoding RNAs (DElncRNAs) were identified; TCONS_00063335 and TCONS_00019814 were identified as candidate lncRNAs potentially associated with melanogenesis-related genes, including TYR and TYRP1. A putative ceRNA network was constructed based on the predicted miRNA-mRNA and miRNA-lncRNA relationships, and ENSAPLT00000025522-apl-miR-11588-3p-MAPK8IP3 was identified as a candidate network relationship associated with MAPK-related pigmentation pathways. However, because this relationship was inferred mainly from bioinformatic prediction and expression association analysis, further functional validation is required to confirm whether it contributes to melanogenesis regulation. These findings provide candidate transcriptomic and noncoding RNA information for the further investigation of tissue-specific pigmentation in Liancheng white ducks.

The BMP and activin membrane-bound inhibitor (BAMBI) gene is a pseudoreceptor involved in TGF-β signaling and plays an important role in follicular development. This study investigated the regulatory effects of BAMBI on the proliferation, apoptosis, and hormone secretion of follicular granulosa cells (GCs) in Jinding duck (Anas platyrhynchos domesticus). The recombinant plasmid duck BAMBI-pcDNA3.1 × 3Flag was successfully constructed, and both interference and overexpression systems were effectively expressed in GCs.EdU incorporation assays demonstrated that BAMBI interference significantly enhanced GC proliferation and upregulated the proliferating cell nuclear antigen (PCNA) expression, whereas BAMBI overexpression markedly inhibited proliferation and reduced PCNA mRNA and protein levels. Flow cytometry analysis showed that BAMBI interference decreased the apoptosis rate, while BAMBI overexpression increased it. Consistently, the expression of pro-apoptotic factors (Bax and Cleaved Caspase-3) was downregulated, and anti-apoptotic Bcl-2 was upregulated after BAMBI interference; the opposite trend occurred with BAMBI overexpression. ELISA and qRT-PCR analyses indicated that BAMBI interference significantly increased the levels of estradiol (E2) and prolactin (PRL), and upregulated the expression of their receptor genes ESR1, PRLR, and FSHR, while LHR expression was decreased. Conversely, BAMBI overexpression decreased E2 and PRL levels and induced opposite changes in receptor gene expression. In conclusion, BAMBI negatively regulates granulosa cell proliferation and is associated with reduced steroid hormone production while promoting apoptosis in Jinding duck granulosa cells in vitro. These findings provide new insights into the molecular mechanisms underlying follicular development and contribute to understanding the genetic regulation of reproductive traits in poultry.

To elucidate the specific role and mechanism of IGF2 (a strongly selected gene in egg-production traits identified in our previous genome resequencing of Chinese Jinding ducks) in duck ovaries, this study investigated the expression and distribution of IGF2, assessed its impact on the proliferation of duck ovarian granulosa cells (GC), and elucidated the underlying regulatory mechanisms. The expression of IGF2 mRNA in the ovary was significantly higher than in all other tissues (P<0.05), being 5.69 times that in the liver the tissue with the second-highest expression. Its protein was mainly located in GC, oocyte cytoplasm and vascular endothelium of duck follicles. In vitro experiments demonstrated that IGF2 enhanced the proliferation of duck GC. Further mechanistic analysis showed that IGF2 promoted the phosphorylation of PI3K and AKT, as well as the expression of downstream CCND3 gene, a cell cycle regulation gene. These findings suggested that IGF2 regulated duck GC proliferation through the PI3K/AKT/CCND3 pathway, thereby affecting the laying traits of ducks. These results revealed a regulatory role of IGF2 in duck follicular development via the PI3K-AKT pathway and extended the existing understanding of IGF2 function in ducks.

Meat quality characteristics are important economic traits of ducks. To identify the molecular bases of these traits, we performed an integrated multi-omics analysis (metabolomics, transcriptomics, and miRNAomics) that compared the breast muscle of 300-day-old Liancheng white duck (LD), which is a lean-type breed prized for its soup flavor, and traditional meat duck Cherry Valley duck (CD), which is a fast-growing fat-type breed used for roasting. The results show that LD had higher levels of amino and bile acids, while CD had higher levels of carbohydrates. Integration analysis revealed key breed-specific molecular signatures. In LD, upregulation of the amino acid transporters SLC7A6 and SLC6A9 related to amino acid transport was consistent with elevated intramuscular amino acids. For carbohydrate metabolism, SOCS3-a well-established negative regulator of glucose uptake in mammalian skeletal muscle-was significantly upregulated in LD, consistent with their lower intramuscular carbohydrate levels. SLC6A9 and SOCS3 were predicted to be negatively regulated by oan-miR-1386. In LD, upregulation of the bile acid biosynthesis gene CH25H paralleled the higher bile acid content, suggesting complex, tissue-specific regulation of these pathways. This integrated analysis provides a resource for candidate genes, miRNAs, and metabolic pathways underlying breed-specific meat quality traits in ducks. The findings generate testable hypotheses for future functional studies and offer potential molecular targets for breeding strategies aimed at improving poultry meat quality.

This study aimed to investigate the potential role of 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3) in steroidogenesis and its possible involvement in germ cell development and meiotic initiation in ducks. Primordial germ cells (PGCs) were isolated from duck embryos and characterized by epithelioid adherent morphology, with more than 90% of cells showing positive expression of c-kit. Functional analyses indicated that overexpression of 17β-HSD3 was associated with increased PGC proliferation (48 h, P < 0.05; 72 h, P < 0.01) and reduced apoptosis (P < 0.0001). In addition, 17β-HSD3 overexpression was correlated with a numerical increase in AKR1D1 expression (P > 0.05) and a significant decrease in P450scc expression (P < 0.001). Retinoic acid (RA) treatment (0.25-1 μM) showed a tendency toward cell cycle progression, as reflected by a decrease in the G0/G1 phase population and an increase in S phase cells, although these changes did not reach statistical significance (P > 0.05). Furthermore, RA exposure was significantly associated with increased expression of 17β-HSD3, Cvh, and Stra8, and decreased expression of pluripotency-associated genes Itga6 and Sox2 (P < 0.001 or P < 0.0001), suggesting molecular changes consistent with meiotic entry. Collectively, these results suggest that 17β-HSD3 may be involved in the modulation of steroidogenesis-related gene expression in duck germ cells and is associated with germ cell proliferation and meiotic initiation. This study provides preliminary evidence that may contribute to the understanding of molecular mechanisms underlying avian germ cell development and reproductive regulation in poultry.

This study aimed to investigate the effects of replacing soybean meal with an equivalent amount of fermented feed on the production performance of laying hens. A total of 480 healthy, 70-week-old Hy-Line Sonia laying hens were divided into three groups, with four replicates of 40 chickens in each group. The control group (NT) was fed a basal diet, while the experimental groups were fed with a diet in which soybean meal was replaced with an equivalent amount of fermented feed: 5 % replacement in treatment group 1 (TT1) and 10 % replacement in treatment group 2 (TT2). At 8 weeks after soybean meal replacement, the results showed that the abnormal egg rate in the 10 % fermented feed group was significantly reduced. Egg quality parameters, such as eggshell strength and thickness, significantly improved in both the TT1 and TT2 groups after 4 and 8 weeks of equivalent soybean meal replacement. The drip loss of breast muscle was significantly lower in the TT1 and TT2 groups compared to the NT group at both 4 and 8 weeks. In addition, there was a significant increase in the pH of thigh muscle at 0 h postmortem and a significant reduction in the fat and cholesterol contents in the muscles of laying hens in the TT1 and TT2 groups. Replacement of 10 % soybean meal with an equivalent amount of fermented feed for 8 weeks yielded a satisfactory effect.

VIPR1 can specifically bind VIP, a PRL release factor, which promotes the secretion of PRL from the pituitary gland, and participates in the regulation of bird nesting behavior. The purpose of this study was to investigate the effects of miR-317 overexpression or silencing on VIPR1 gene and protein expression in duck follicle granulosa cells. The ovaries of Muscovy ducks were collected during the nesting and laying periods, and histological differences were analyzed via HE staining. Duck primary follicle granulosa cells were isolated and identified by immunofluorescence staining, after which the cells were transfected with miR-317, mimic-NC, miR-317 mimic, inhibitor-NC or miR-317 inhibitor Alterations in cell proliferation were then analyzed by EdU staining, and cell apoptosis was assessed by Annexin-V-FITC flow cytometry and TUNEL staining. Fluorescence quantitative PCR was used to assess the expression level of VIPR1 after miR-317 overexpression or silencing. Total protein was extracted from the follicle granulosa cells, and protein levels were analyzed via Western blotting. The results revealed that the nucleus of the ovarian granule in Muscovy ducks was more concentrated and distinct from the surrounding cells during the brooding period than during the laying period. More than 90% of the cells were identified as duck follicle granulosa cells by immunofluorescence staining of FSHR and LHR. miR-317 expression was significantly higher in the miR-317 mimic-transfected group than in the miRNA-NC-transfected group (P < 0.01); similarly, miR-317 expression was significantly lower in the inhibitor-transfected group than in the miRNA inhibitor-transfected group (P < 0.01), indicating that miR-317 overexpression and interference vectors were successfully constructed and transfected into duck follicular granulosa cells. EdU staining revealed that the number of EdU-positive cells was significantly greater in the miR-317 mimic-transfected group than in the mimic-NC-transfected group (P < 0.05); after miR-317 silencing or inhibition, cell proliferation decreased, and the number of EdU-positive cells significantly decreased (P < 0.01). TUNEL staining revealed that the proportion of red, TUNEL-positive cells in the miR-317 inhibitor interference group was significantly greater than that in the miR-NC, miR-317 mimic, or inhibitor-NC group (P < 0.05). These results suggest that miR-317 inhibition promoted the apoptosis of duck follicle granulosa cells. Flow cytometry revealed that the percentage of apoptotic cells was 14.23% and 22.75% in the inhibitor-NC and miR-317 inhibitor groups, respectively (P < 0.01). Fluorescence quantitative PCR revealed that, compared with that in the corresponding control groups, VIPR1 gene expression was significantly lower in the miR-317 mimic group (P < 0.05) but significantly higher in the miR-317 inhibitor group (P < 0.05). Western blot analysis revealed that VIPR1 levels were significantly lower in the miR-317 mimic group than in the mimic-NC group (P < 0.05) but significantly greater in the miR-317 inhibitor group (P < 0.05). In summary, miR-317 inhibition promoted the apoptosis of duck follicle granulosa cells, and miR-317 overexpression promoted the proliferation of duck follicle granulosa cells and negatively regulated expression of the target gene VIPR1 at the gene and protein levels. This study further reveals the molecular mechanism underlying follicular atresia and serves as a reference for reducing the broodiness of Muscovy ducks.

This study aimed to investigate the role of a novel duck miR-290, which targets Phosphatidyqinositol-3 kinase (PI3K), in regulating melanogenesis in Liancheng white ducks. Differentially expressed miRNAs (DEmiRNA) associated with melanogenesis were first screened by transcriptome sequencing of mouth skin and skin from 130-day-old Liancheng white ducks. The interaction between novel miR-290 and the PI3K 3′UTR was verified by a dual-luciferase reporter assay. Primary duck melanocytes were then isolated from the mouth skin tissue, and the function of miR-290 was examined at the cellular level. The results revealed that novel miR-290 directly targeted PI3K, and the levels of p-PI3K and p-AKT were significantly decreased in the mouth skin compared with skin (P < 0.05), whereas p-GSK3β, Integrin-linked kinase (ILK), Microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), and Melanocortin 1 Receptor (MC1R) were significantly increased in the mouth skin(P < 0.05). The isolated melanocytes were spindle-shaped and positive for DOPA and melanocytic markers.Overexpression of miR-290 significantly promoted melanocyte proliferation and melanin production (P < 0.01);(RT-qPCR) and Western blot analysis revealed that miR-290 inhibited the expression of PI3K and protein kinase B (AKT) (P < 0.05) and increased the expression of ILK, Glycogen Synthase Kinase 3β (GSK3β), MC1R, MITF, TYR, tyrosinase-related protein 1 (TYRP1), and tyrosinase-related protein 2 (TYRP2) (P < 0.05). In conclusion, this study identifies a novel duck miR-290 as a positive regulator of melanogenesis, which promotes melanocyte proliferation and melanin synthesis in Liancheng white ducks by suppressing PI3K/AKT signaling and activating downstream melanogenic genes.

Heat stress (HS) is a critical factor affecting the health and performance of poultry. This study investigated the effects of varying durations of HS on antioxidant capacity and intestinal damage in Jinding ducks. The ducks were exposed to an environment at 40°C for 1 h, 3 h, 6 h, and 12 h to simulate HS conditions. The impact of HS on intestinal health was assessed by measuring the expression of small intestinal heat shock proteins, inflammatory factors, intestinal digestive enzyme activity, intestinal permeability, and pathomorphological changes in the jejunum. The results showed that with prolonged HS, the expression of antioxidant capacity and heat shock proteins initially increased and then decreased, while intestinal inflammation and damage progressively intensified. Notably, after 12 h of HS, there was a significant increase in intestinal permeability, impaired barrier function, decreased digestive enzyme activity, pronounced disturbances in jejunal morphology, and a substantial reduction in immune cell numbers. These findings suggest that Jinding ducks subjected to 12 h of HS at 40°C can serve as a model for acute HS. This study not only elucidated the alterations in antioxidant and intestinal immunity in Jinding ducks associated with extended HS but also provided a scientifically robust experimental model for future research on anti-HS agents. The results were significant for a deeper understanding of the mechanisms through which HS affects poultry health and offered a scientific basis for developing new strategies to mitigate HS impacts.

Indigenous chicken breeds from Fujian Province, China, exhibit unique and distinctive phenotypic characteristics, including morphology, behaviour, integumentary pigmentation, feather colouration, and production performance. However, the underlying genetic basis governing these specific traits remains unclear. This study aimed to elucidate the population structure of six Fujian local chicken breeds [Bairong chickens (BRCs), Jinhu chickens (JHCs), Minqing chickens (MQCs), Dehua chickens (DHCs), Xiangdong chickens (XDCs), and Hetian chickens (HTCs)] in terms of their genetic resources within the province. The whole-genome resequencing revealed 8 678 612 single nucleotide polymorphisms (SNPs) in a cohort of 36 chickens. The results revealed a partial mismatch between the clustering patterns and geographic distributions of the six populations, with BRC displaying a noticeable genetic divergence from other chickens. Moreover, the genetic distance between XDC and HTC in Longyan County was relatively close and converged with JHC, MQC, and DHC into a subgroup. These findings provide a comprehensive understanding of the intrinsic characteristics and utilisation prospects of chicken germplasm resources in Fujian Province.

The assessment of animal genetic structure had significant importance for the preservation and breeding of animal germplasm resources. Selection signals are genotype markers generated during the process of biological evolution, and the detection of selection signals could reveal the direction of species evolution. The aim of this study was to generate a whole-genome resequencing data from Jinding duck, Shanma duck, Youxian Partridge duck, and Taiwan Brown tsaiya duck to reveal their population structure and selection signals. The population structure analysis revealed significant genetic differences among the four indigenous laying ducks, indicating their independent lineage. Specifically, Shanma duck and Youxian partridge duck were closely and likely originated from a common ancestor. In addition, selection sweep analysis was performed using the population genetic differentiation coefficient (Fst) and nucleotide diversity ratio (π ratio). The top 5% was used as the threshold for the Fst and π ratio, and the two thresholds were combined to identify selected genomic regions. In the selected regions of the three comparison groups, 136, 143 and 268 candidate genes were detected. Further screening of all candidate genes revealed that 35 candidate genes appeared simultaneously in three comparative groups, with 16 genes annotated. The 16 genes were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The results revealed 5 functional genes (AQP3, PIK3C3, NOL6, RPP25, and DCTN3) that may be related to important economic traits in laying ducks and involved mainly invasopressin-regulated water reabsorption, ribosome biogenesis, and the PI3K signaling pathway. The results provide insights into the protection and exploitation of genetic resources of Chinese indigenous laying ducks.

The aim of the study was to explore the regulatory mechanism of differences in embryonic gonadal development between intergeneric distance hybrid offspring Mulard ducks and parent ducks. The morphological differences gonadal tissues of Muscovy ducks, Pekin ducks and Mulard ducks at 12.5-day embryonic age were observed by sectioning and hematoxylin-eosin (HE) staining. Then followed by transcriptome sequencing to screen for gonadal development-related differentially expressed circRNAs and mRNAs to construct a competitive endogenous RNA (ceRNA) regulatory network. Finally, qRT-PCR and luciferase reporter system were used to verify the sequencing data and targeting relationship of ceRNA pairs. The results showed that the seminiferous tubule lumen of Mulard ducks was not obvious, while there were obvious seminiferous tubules and tubular structures in testis of Pekin ducks and Muscovy ducks, with number and shape indicating maturity. There were 18 upregulated circRNAs and 16 downregulated circRNAs in Mulard ducks and Pekin ducks, respectively, and 39 upregulated circRNAs and 1 downregulated circRNA in Mulard ducks and Muscovy ducks, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis found that genes involves in dorso-ventral axis formation, for example, neurogenic locus notch homolog protein 1 (NOTCH1), were significantly enriched (P < 0.05). The novel_circ_0002265-gga-miR-122-5p-PAFAH1B2 regulatory network was constructed. The qRT-PCR results showed that the sequencing results were reliable. The dual-luciferase reporter assay showed that gga-miR-122-5p exists binding site of circ_0002265 and PAFAH1B2, indicating circ_0002265-gga-miR-122-5p-PAFAH1B2 targeting relationship. In summary, the embryonic gonadal development of intergeneric hybrid Mulard ducks may be regulated by differentially expressed circRNAs and genes, such as novel_circ_0000519, novel_circ_0003537, NOTCH1, FGFR2, PAFAH1B1, and PAFAH1B2, among which circ_0002265-gga-miR-122-5p-PAFAH1B2 may participate in the targeted regulation of gonadal development in Mulard ducks. The findings of this study are helpful for analyzing the mechanism of embryonic gonadal development differences in avians.

To explore the differential regulation mechanism of heat stress on the egg production performance and egg quality of Jinding ducks, 200 Jinding ducks (360-day-old) in good health and with similar body weights and a normal appetite were selected and randomly divided into a control (normal temperature [NT]) group (20°C-25°C) and a heat stress (HS) group (32°C-36°C), with 4 replicates in each group and 25 ducks in each replicate. The pretrial period was 1 wk, and the formal trial period was 4 wk. At the end of the 4th wk, 12 duck eggs were collected from each replicate to determine egg quality. Pituitary and ovarian tissues of Jinding ducks were collected, transcriptome sequencing was performed to screen differentially expressed miRNAs and mRNAs related to high temperature and heat stress, and a competitive endogenous RNA regulatory network was constructed. The sequencing data were verified by qRT‒PCR method. The following results were obtained: (1) Compared with the NT group, the HS group had a significantly lower laying rate, total egg weight, average egg weight, total feed intake, and feed intake per duck (P < 0.01), an extremely significantly higher feed-to-egg ratio (P < 0.01), and a higher mortality rate. (2) Compared with the NT group, the HS group had an extremely significantly lower egg weight, egg yolk weight, eggshell weight, and eggshell strength (P < 0.01) and an extremely significantly lower yolk ratio and eggshell thickness (P < 0.01, P < 0.05); however, there was no significant difference in the egg shape index, Haugh unit or protein height (P > 0.05). (3) A total of 1,974 and 1,202 genes were identified in the pituitary and ovary, respectively, and there were 5 significantly differentially expressed miRNAs. The differentially expressed genes were involved in the arginine and proline metabolism pathways, ether lipid metabolism pathway, and drug metabolism-cytochrome P450 pathway, which are speculated to be related to the egg production performance of Jingding ducks under high-temperature heat stress. (4) Novel_221 may target the PRPS1 gene to participate in egg production performance; novel_168 and novel_289 may target PIGW; novel_289 may target Q3MUY2; and novel_289 and novel_208 may target PIGN or genes that may be related to high-temperature heat stress. (5) In pituitary tissue, upregulated novel_141 (center of the network) formed a regulatory network with HSPB1 and HSP30A, and downregulated novel_366 (center of the network) formed a regulatory network with the JIP1 gene. In ovarian tissue, downregulated novel_289 (center of the network) formed a regulatory network with the ZSWM7, ABI3, and K1C23 genes, novel_221 formed a regulatory network with the IGF1, BCL7B, SMC6, APOA4, and FARP2 genes, and upregulated novel_40 formed a regulatory network with the HA1FF10 gene. In summary, heat stress affects the production performance and egg quality of Jinding ducks by regulating the secretion of endocrine-related hormones and the release of neurotransmitters as well as the expression of miRNAs and mRNAs in pituitary and ovarian tissues. The miRNA‒mRNA regulatory network provides a theoretical basis for the molecular mechanism that regulates the stress response in pituitary and ovarian tissues, egg quality, and production performance under heat stress.

为了比较分析不同品种(品系)蛋鸭蛋品质的差异性与相关性,试验随机选取300日龄连城白鸭、连城白鸭青壳系、金定鸭、台湾褐色菜鸭、龙岩山麻鸭和攸县麻鸭的鸭蛋各30个进行蛋品质测定.结果显示:金定鸭蛋重和蛋壳重极显著或显著高于其他品种(P＜0.01或P＜0.05);台湾褐色菜鸭、龙岩山麻鸭、攸县麻鸭的蛋黄比率极显著高于其他三个品种(P＜0.01);台湾褐色菜鸭的蛋形指数最大,极显著高于其他品种(P＜0.01);连城白鸭青壳系蛋壳强度最大,极显著高于台湾褐色菜鸭、龙岩山麻鸭和攸县麻鸭(P＜0.01);连城白鸭哈氏单位最高,极显著高于台湾褐色菜鸭、龙岩山麻鸭和攸县麻鸭(P＜0.01).蛋品质相关分析发现,蛋黄比与蛋黄重极显著正相关(P＜0.01),与蛋壳重、壳重比、哈氏单位、蛋白高度等极显著负相关(P＜0.01).壳重比与蛋重、蛋黄重、蛋黄比极显著负相关(P＜0.01),与蛋壳重、蛋壳厚度、蛋壳强度极显著正相关(P＜0.01),与哈氏单位显著正相关(P＜0.05).哈氏单位与蛋白高度极显著正相关(P＜0.01).对相关性状进行主成分分析,可提取3个主成分,累计贡献率为72.7％,建立鸭蛋品质主成分综合评价型(Y=0.592x1+0.616x2+0.425x3+0.440x4+0.236x5+0.253x6-0.733x7-0.583x8).研究表明,针对蛋重,可以金定鸭作为育种素材;针对蛋黄重和蛋黄比率,可以台湾褐色菜鸭、龙岩山麻鸭、攸县麻鸭作为育种素材;针对蛋壳厚度、蛋壳强度、蛋白高度和哈氏单位,可以金定鸭、连城白鸭或连城白鸭青壳系作为育种素材,与其他优良品种进行杂交选育,达到选育目的.

为研究连城白鸭青壳系与连城白鸭在蛋品质与营养成分方面的差异,随机挑选300日龄连城白鸭青壳系和连城白鸭所产鸭蛋各120个,对蛋重、蛋黄比率、蛋形指数、蛋黄颜色、蛋壳强度、哈氏单位、蛋白高度、蛋壳厚度、水分、蛋白质、脂肪、灰分、胆固醇、钙、铁、锌、脂肪酸含量、氨基酸含量等指标进行测定分析.结果显示:连城白鸭青壳系的蛋形指数、蛋壳厚度极显著高于连城白鸭(P<0.01),蛋重、蛋黄比率、脂肪酸含量、谷氨酸含量、顺-9-十六碳一烯酸甲酯、顺-9-十八碳一烯酸甲酯和顺,顺-9,12-十八碳二烯酸甲酯含量显著高于连城白鸭(P<0.05),蛋氨酸、胆固醇含量显著低于连城白鸭(P<0.05).结果表明,连城白鸭青壳系在保持连城白鸭的外貌特征基础上,提高了蛋重、蛋黄比率、谷氨酸含量和脂肪酸含量,降低蛋氨酸和胆固醇含量.

In duck breeding, the growth and development of skeletal muscle is an important factor influencing the meat production performance of ducks. Therefore, the determination of Myod and Myf5 gene expression in poultry skeletal muscle tissues can help to understand the muscle development of poultry, improve the production performance and feed conversion rate of animal organism, enhance the rapid protein deposition in animal organism, and obtain high quality and quantity of animal livestock products. In this study, a fluorescent PCR assay system for Myod and Myf5 genes was developed, and a dual integrated rapid detection platform suitable for detecting Myod and Myf5 genes in poultry muscle tissue with a sensitivity of 10 copies/ μ L was constructed using a set of commercial, fully automated nucleic acid analyzer with integrated detection based on magnetic bead method for nucleic acid extraction and PCR fluorescence detection. For 20 simulated samples, the integrated detection system was consistent with the results of qPCR experiments after conventional laboratory extraction, while the closed cassette-based detection reduced the chance of contamination occurrence, making the results more reliable and accurate, which is ideal for immediate on-site rapid detection.

Liancheng white duck is a typical local duck breed in Fujian Province famous for its meat traits. To better understand how meat quality varies with breed, the chemical composition of breast meats of Liancheng white ducks (LD) and Cherry Valley ducks (CD) were examined using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS).The correlation between meat quality and the differential metabolites was further analyzed. The results showed that the effects of breed on duck breast meat were significant for pH, color, cooking loss, and shear force. Liancheng white duck breast meat exhibited a higher shear force and pH, and lower cooking loss and lightness (L*24), redness (a*24), and yellowness (b*24) than CD. Metabolomic analysis revealed significant differences between the meat extracts from the 2 duck breeds. A total of 49 and 57 significantly different metabolites were identified in positive and negative ion modes, respectively. These differentially accumulated metabolites (DAMs) could be divided into 28 classes, of which the 4 main categories were carbohydrates, amino acids, fatty acids, and eicosanoids. Liancheng white duck might have better nutritional and medicinal value considering the higher content of (4Z,7Z,10Z,13Z,16Z,19Z)-4,7,10,13,16,19-docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), eicosapentaenoic acid (EPA), and prostaglandinF3α (PGF3α), having anti-inflammatory orantioxidant effects. Carbohydrate concentration negatively correlated with pH24. The 4 metabolites positively correlated with the shear force. These results provide an overall perspective for bridging the gap between variation of duck meat quality and metabolites with respect to breed.

为河田鸡种质资源保护和选育提供数据依据,试验随机抽取150日龄河田鸡40只(公母各半),测定了 6个体尺性状(体斜长、龙骨长、胸深、胸宽、胫长、胫围)和7个屠宰性能指标(宰前活重、屠体重、半净膛重、全净膛重、胸肌重、腿肌重、腹脂重),并对这13个指标进行相关性分析和主成分分析.结果表明:河田鸡公鸡的体尺性状均极显著高于母鸡(P＜0.01),除腹脂重极显著小于母鸡外,公鸡的屠宰性能指标均极显著高于母鸡(P＜0.01).相关性方面,河田鸡体尺性状和屠宰性能间均存在不同程度的相关,且在性别间存在一定差异.体尺性状中的体斜长、龙骨长、胸深、胸宽与屠宰性能中的宰前活重、屠体重、半净膛重、全净膛重高度相关,表现为显著(P＜0.05)或极显著(P＜0.01).主成分分析中,按特征向量和贡献率可将公鸡性状指标简化为3个主成分屠宰因子、胫围因子和龙骨长因子,累计贡献率为80.231％,母鸡的性状指标简化为2个主成分屠宰因子和胫长因子,累计贡献率为78.245％.研究表明体尺性状与屠宰性能的相关性和主成分分析对河田鸡的种质资源保护和选育提供数据参考.

[目的]探索福建省农业科学院畜牧兽医研究所在连城白鸭原种基础上选育的连城白鸭青壳新品系的生长规律,为连城白鸭新品系的 0～17 周的生长性能提供参考依据.[方法]测定连城白鸭青壳新品系的 0～17 周体重数据,对该数据进行分析和拟合Gompertz、Logistic和Von Bertalanff等 3 种生长拟合曲线模型.[结果]Gompertz、Logistic和Von Bertalanffy三种拟合曲线模型的极限体重(A)分别为 1 542.032 g、1 510.456 g和 599.036 g,拐点周龄分别 3.97 周、4.99 周和 8.26 周,拐点体重分别为567.28 g、755.23 g和 177.49 g,拟合度(R2)分别为 0.997、0.998 和 0.954.Gompertz和Logistic两个生长拟合曲线模型均能很好地拟合连城白鸭青壳新品系母鸭的生长发育过程,而Von Bertalanffy生长拟合曲线模型并不能很好地拟合青壳新品系母鸭的生长发育过程,与实际观测生长曲线出入较大.[结论]Logistic模型拟合的连城白鸭青壳新品系母鸭生长曲线效果最佳(R2=0.998).连城白鸭青壳新品系母鸭的极限体重为 1 510.456 g,拐点周龄为 4.99 周,拐点体重为 755.23 g,可对连城白鸭青壳新品系的生长规律进行评估和预测.