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Simple Summary: The low laying performance of geese has significantly hindered the development of the goose breeding industry. The growth and development of goose follicle granulosa cells (GCs) directly influence normal ovulation in geese, which in turn impacts egg production. Our previous data suggest that de novo lipogenesis (DNL) occurs within the GCs of goose follicles. In this study, we investigated the potential mechanism of action of the PLIN1 gene in goose GCs for the first time, using cell culture, transfection, and transcriptome sequencing technologies. The results of the transcriptome analysis indicated that PLIN1 may regulate oxidative stress in goose follicular granulosa cells through the TGF-β signaling pathway, thereby inducing cell proliferation or apoptosis. Additionally, nine candidate genes were identified as potentially involved in this process. These findings enhance the understanding of the molecular regulatory mechanisms in goose follicular GCs and provide a theoretical foundation for future in-depth studies on these molecular mechanisms. PLIN1, a member of the PAT family, is expressed in both adipocytes and steroidogenic cells. In this study, we used cell transfection technology combined with transcriptome sequencing to investigate the regulatory mechanism of PLIN1 in goose follicular GCs. Gene Ontology (GO) analysis revealed that in the four groups (phGC: over_vs_over-NC; hGC: over_vs_over-NC; phGC: si_vs_si-NC; hGC: si_vs_si-NC), most differentially expressed genes (DEGs) were significantly enriched (p < 0.05) in pathways related to biological processes (BPs), particularly those associated with the regulation of cellular lipid metabolism and oxidative stress. KEGG analysis further identified significant enrichment (p < 0.05) in pathways related to cell apoptosis and the cell cycle. A joint analysis of KEGG and PPI on the upregulated and downregulated DEGs revealed that the TGF-β signaling pathway was the only pathway significantly enriched among both upregulated and downregulated DEGs after PLIN1 overexpression in hGCs and phGCs. Based on these findings, we hypothesize that PLIN1 overexpression may promote granulosa cell proliferation and apoptosis by activating the TGF-β signaling pathway in goose follicular GCs. Additionally, nine potential candidate genes were identified: PPARγ, MGLL, PTEN, BAMBI, BMPR2, JUN, FST, ACSF3, and ACSL4. These results address a significant research gap concerning the role of this gene in granulosa cells and contribute to the understanding of its molecular regulatory mechanisms. [ABSTRACT FROM AUTHOR]

Simple Summary: The genetic basis underlying the pigmentation pattern of duck feathers requires extensive study. Major genes related to diverse color patterns of duck feathers remain unknown. Therefore, in this study, a genome-wide association study was used to reveal genes responsible for variations in the color pattern of single feathers of ducks. The results from this study revealed that the variation in color patterns on the left and right sides of the single feathers is associated with genes that are responsible for regulating pigment deposition and migration in the feather follicles of Tianfu Nonghua ducks. In this study, WNT3A, DOCK1, RAB1A, and ALDH1A3 were identified as the candidate genes associated with different pigmentation patterns on the left and right sides of the single feather, as well as on the dorsal and ventral feathers. In modern advanced genetics and breeding programs, the study of genes related to pigmentation in ducks is gaining much attention and popularity. Genes and DNA mutation cause variations in the plumage color traits of ducks. Therefore, discovering related genes responsible for different color traits and pigment patterns on each side of the single feathers in Chinese ducks is important for genetic studies. In this study, we collected feather images from 340 ducks and transported them into Image Pro Plus (IPP) 6.0 software to quantify the melanin content in the feathers. Thereafter, a genome-wide association study was conducted to reveal the genes responsible for variations in the feather color trait. The results from this study revealed that the pigmented region was larger in the male ducks as compared to the female ducks. In addition, the pigmented region was larger on the right side of the feather vane than on the left side in both dorsal and ventral feathers, and a positive correlation was observed among the feather color traits. Further, among the annotated genes, WNT3A, DOCK1, RAB1A, and ALDH1A3 were identified to play important roles in the variation in pigmented regions of the various feathers. This study also revealed that five candidate genes, including DPP8, HACD3, INTS14, SLC24A1, and DENND4A, were associated with the color pigment on the dorsal feathers of the ducks. Genes such as PRKG1, SETD6, RALYL, and ZNF704 reportedly play important roles in ventral feather color traits. This study revealed that genes such as WNT3A, DOCK1, RAB1A, and ALDH1A3 were associated with different pigmentation patterns, thereby providing new insights into the genetic mechanisms of single-feather pigmentation patterns in ducks. [ABSTRACT FROM AUTHOR]

Simple Summary: Poultry laying performance depends on the normal development of ovarian follicles. Lipid metabolism and steroidogenesis in granulosa cells are essential for maintaining normal follicular development; therefore, a detailed understanding of the molecular mechanisms underlying granulosa cell functions may provide a basis for improving production. In the present study, we investigated the effects of miR-202-5p, which show expression changes during follicular development, on lipid metabolism and steroidogenesis in goose hierarchical follicular granulosa cells. We found that miR-202-5p significantly inhibited lipid deposition and steroid hormone production in goose hierarchical follicles granulosa cells via ACSL3. These results revealed the important role of miR-202-5p in the regulation of goose granulosa cell functions and demonstrate that this miRNA is a potential target for molecular breeding. miRNAs are critical for steroidogenesis in granulosa cells (GCs) during ovarian follicular development. We have previously shown that miR-202-5p displays a stage-dependent expression pattern in GCs from goose follicles of different sizes, suggesting that this miRNA could be involved in the regulation of the functions of goose GCs; therefore, in this study, the effects of miR-202-5p on lipid metabolism and steroidogenesis in goose hierarchical follicular GCs (hGCs), as well as its mechanisms of action, were evaluated. Oil Red O staining and analyses of intracellular cholesterol and triglyceride contents showed that the overexpression of miR-202-5p significantly inhibited lipid deposition in hGCs; additionally, miR-202-5p significantly inhibited progesterone secretion in hGCs. A bioinformatics analysis and luciferase reporter assay indicated that Acyl-CoA synthetase long-chain family member 3 (ACSL3), which activates long-chain fatty acids for the synthesis of cellular lipids, is a potential target of miR-202-5p. ACSL3 silencing inhibited lipid deposition and estrogen secretion in hGCs. These data suggest that miR-202-5p exerts inhibitory effects on lipid deposition and steroidogenesis in goose hGCs by targeting the ACSL3 gene. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, some studies have found that epididymis could affect the reproductive performance of poultry. In drakes, the semen volume is regulated by epididymis, and the semen volume is the key to limit the ratio of male and female during artificial insemination. Therefore, the present study compared the histomorphology and transcriptome level differences in the epididymis of drakes with high- and low-volume semen. After bioinformatics analysis, nine differentially expressed genes (including SLC18A2, SNAP25, CACNA1B, GABRG2, DRD3, CAMK2A, NR5A1, and STAR) that up-regulated in the high-volume semen group and could regulate mutually were screened. The results reveal that the nine genes could affect the semen volume of drakes by regulating the synthesis of steroid hormones in epididymis. These results provide a new insight into the molecular mechanism regulating semen volume of drakes. Semen volume is an important factor in artificial insemination (AI) of ducks. In drakes, seminal plasma that is produced by the epididymis determines the semen volume. However, the mechanism of epididymis regulating semen volume of drakes remains unclear. Therefore, the aim of the present study was to preliminarily reveal the mechanism regulating the semen volume through comparing the epididymal histomorphology and mRNA expression profiles between drakes with high-volume semen (HVS) and low-volume semen (LVS). Phenotypically, drakes in the HVS group produced more sperm than drakes in the LVS group. In addition, compared with the HVS group, the ductal square of ductuli conjugentes (DC) and dutus epididymidis (DE) in epididymis was significantly smaller in the LVS group, and the lumenal diameter and epithelial thickness of DC/DE were significantly shorter in the LVS group. In transcriptional regulation, 72 different expression genes (DEGs) were identified from the epididymis between HVS and LVS groups. Gene Ontology (GO) analysis indicated that the DEGs were mainly related to hormone secretion, neurotransmitter synthesis/transport, transmembrane signal transduction, transmembrane transporter activity, and nervous system development (p < 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis showed that the DEGs were significantly enriched in pathways associated with hormone and neurotransmitter transmission (p < 0.05). In addition, further analysis of the top five pathways enriched by KEGG, nine key candidate genes (including SLC18A2, SNAP25, CACNA1B, GABRG2, DRD3, CAMK2A, NR5A1, and STAR) were identified, which could play a crucial role in the formation of semen. These data provide new insights into the molecular mechanism regulating semen volume of drakes and make feasible the breeding of drakes by semen volume. [ABSTRACT FROM AUTHOR]

Simple Summary: For birds, the uropygial gland is a special organ. We believe that its secretion can be used as a pheromone between the sexes to play a role in mate selection and mating. Therefore, we studied the chemical composition of duck uropygial gland secretions and the differences between males and females. After a series of screenings, 24 different volatile metabolites were obtained in our experiment. On this basis, five extremely significant volatile metabolites were screened out—significantly more males than females. The results show that these volatile substances are potential sex pheromone substances, which may be the critical olfactory clues for birds to choose mates. Our results lay the foundation for further research on whether uropygial gland secretion affects duck reproduction and production. The exchange of information between animals is crucial for maintaining social relations, individual survival, and reproduction, etc. The uropygial gland is a particular secretion gland found in birds. We speculated that uropygial gland secretions might act as a chemical signal responsible for sexual communication. We employed non-targeted metabolomic technology through liquid chromatography and mass spectrometry (LC-MS) to identifying duck uropygial gland secretions. We observed 11,311 and 14,321 chemical substances in the uropygial gland secretion for positive and negative ion modes, respectively. Based on their relative contents, principal component analysis (PCA) showed that gender significantly affects the metabolite composition of the duck uropygial gland. A total of 3831 and 4510 differential metabolites were further identified between the two sexes at the positive and negative ion modes, respectively. Of them, 139 differential metabolites were finally annotated. Among the 80 differential metabolites that reached an extremely significant difference (p < 0.01), we identified 24 volatile substances. Moreover, we further demonstrated that five kinds of volatile substances are highly repeatable in all testing ducks, including picolinic acid, 3-Hydroxypicolinic acid, indoleacetaldehyde, 3-hydroxymethylglutaric acid, and 3-methyl-2-oxovaleric acid. All these substances are significantly higher in males than in females, and their functions are involved in the reproduction processes of birds. Our data implied that these volatile substances act as sex pheromones and may be crucial olfactory clues for mate selection between birds. Our findings laid the foundation for future research on whether uropygial gland secretion can affect ducks' reproduction and production. [ABSTRACT FROM AUTHOR]

Simple Summary: With the development of the modern poultry industry, people have gradually transformed the floor rearing system into a cage rearing system. However, due to some factors, including the environment and management, the feather condition of caged ducks is generally poor, which impairs the healthy growth of ducks and the economic efficiency of breeders. It is believed that birds usually collect secretions from their uropygial gland and smear them on their feathers and cuticle scales during preening to improve their waterproofing and resistance to pathogens, thus protecting their health and growth. Therefore, we studied the uropygial glands of ducks in different rearing systems. The results showed that the cage rearing system affected the weight and metabolic components in the uropygial gland of ducks. Caged ducks have a lower relative weight of their uropygial gland and lower levels of certain amino acids and fatty acids that contribute to their development. This allows us to better understand the causes of the poor appearance of feathers in caged ducks. Background: As a unique skin derivative of birds, the uropygial gland has a potential role in maintaining feather health and appearance. Cage-reared ducks usually have a worse feather condition than floor-reared ducks. We suspected that the metabolic components in the uropygial gland might play a vital role in their feather conditions. Methods: Herein, the uropygial glands of floor- and cage-reared ducks were weighed, and a nontargeted metabolic analysis was performed. Results: At 20 weeks of age, the relative weight of floor-reared duck uropygial glands was significantly higher than that of cage-reared ducks, indicating that the floor rearing system is better for inducing the development of uropygial glands. The nontargeted metabolic data revealed 1190 and 1149 differential metabolites under positive and negative ion modes, respectively. Among them, 49 differential metabolites were annotated between the two rearing systems. Three sulfur-containing amino acids, namely, 2-ketobutyric acid, L-aspartate-semialdehyde, and N-formyl-L-methionine, and some lipids, including inositol and sphingosine, might be responsible for the changes in plumage appearance among the various rearing conditions. Conclusions: The results of our study revealed the differences in the metabolic components of the uropygial gland in ducks reared under different rearing systems and found metabolic components to be possibly responsible for the poor feather condition of caged ducks. [ABSTRACT FROM AUTHOR]