Search Results (15)

Intense broodiness restricts egg production in Zhedong White Geese, with prolactin (PRL) being a key regulator. This study aimed to elucidate the role of PRL gene alternative splice variants in regulating broodiness in Zhedong White Geese. A total of 20 Zhedong White Geese at 400 days of age were selected and divided into two groups of 10 based on their physiological states: the laying period and the brooding period. Through bioinformatics and molecular biology approaches, PRL-L and PRL-S were identified and characterized. The results showed that PRL-S lacked a signal peptide and the first 57 amino acids at the N-terminus, leading to the disappearance of its first α-helix structure. Functional validation demonstrated that the recombinant PRL-S protein, prepared using a prokaryotic expression system, possessed physiological activity, including receptor binding and the activation of downstream signaling pathways. Furthermore, Real-time PCR and Western blot analyses revealed that the expression of both splice variants in the hypothalamic–pituitary–ovarian axis exhibited significant spatiotemporal specificity and was closely associated with reproductive states. This study revealed the molecular characteristics, in vitro functional activity, and expression patterns of PRL-S, providing new insights into the regulatory mechanisms of PRL. Full article

Broodiness is a natural behavior whereby female birds stop laying eggs to sit on and hatch them. This behavior is regulated through genetic, hormonal, and environmental factors. The Taihe Black-Boned Silky Fowl (TBSF), a Chinese traditional domestic breed, exhibits a strong brooding tendency; however, the molecular mechanisms underlying this trait remain unclear. In this study, we performed an integrated multi-omics analysis to characterize differences between two groups of TBSF hens: 8 individuals undergoing 30 days of active brooding (BR30) and 8 individuals in the normal laying egg stage (NB), selected from a total group of 230 hens. We combined 16S rRNA sequencing, untargeted metabolomics, and hepatic transcriptome sequencing, with statistical analyses including QIIME 1.9.1, OPLS-DA (VIP > 1), Student’s t-test (p ≤ 0.05), and DESeq2 (|log₂FC| ≥ 1, FDR < 0.05) for differentially expressed genes (DEGs), respectively, and Pearson’s correlation analysis for multi-omics integration. Phenotypically, brooder hens showed significantly reduced feed intake, body weight, and main digestive tissue indices, alongside altered liver and blood biochemical parameters. Hepatic transcriptome analysis identified 1582 DEGs between groups, enriched in pathways related to fatty acid oxidation and the amino acid degradation pathway. In addition, 16S rRNA sequencing revealed distinct gut microbial community structures: the NB group was enriched in Bacilliota and Pseudomonadota, while the BR30 group was enriched in Spirochaetota and Synergistota. Metabolomic profiling identified a total of 143 differential metabolites, which were enriched in lipid and amino acid metabolites, including alpha-linolenic acid and pyruvate metabolites. Multi-omics correlation analysis revealed tight associations between gut microbial taxa, circulating metabolites, and hepatic gene expression. Specifically, beneficial lipid metabolites, including phospholipids, lysophosphatidylcholines, and sphingomyelins, were positively correlated with Synergistes and the Christensenellaceae R-7, as well as with key hepatic lipid metabolism genes FABP1, LPL, and FADS2. In summary, this study reveals that the gut–liver axis plays a critical part in the modulation of energy metabolism during broodiness, and further highlights new insights into metabolic targets that could optimize reproductive behavior and enhance poultry production. Full article

Background: Broodiness is a major limiting factor for reproductive efficiency in indigenous avian breeds, a phenomenon underpinned physiologically by granulosa cell (GC) apoptosis and subsequent follicular atresia. While Serine Protease 23 (PRSS23) has been implicated in mammalian ovarian remodeling, its specific regulatory function in avian follicular dynamics remains elusive. Methods: Utilizing the Wuding chicken—an indigenous breed distinguished by robust environmental adaptability but compromised by high broodiness frequency—as a biological model, this study dissected the molecular mechanism of PRSS23-mediated follicular regression. We cloned the complete coding sequence of the Wuding chicken PRSS23 gene, characterized its spatiotemporal expression profile, and interrogated its function in primary GCs via gain- and loss-of-function assays. Results: RT-qPCR analysis revealed that PRSS23 is differentially expressed across the hypothalamic–pituitary–ovarian (HPO) axis, with ovarian expression being significantly upregulated during the broody period compared to the laying period. Mechanistically, PRSS23 overexpression significantly downregulated the expression of follicle-stimulating hormone receptor (FSHR) and key steroidogenic enzymes (STAR, CYP19A1, HSD3β1), thereby suppressing the expression of genes governing the biosynthesis potential of progesterone and estradiol. Concurrently, PRSS23 overexpression was associated with transcriptional repression of components of the PI3K/AKT/mTOR signaling cascade; this transcriptional regulation further induced cell cycle arrest at the G0/G1 phase, and activated the mitochondrial apoptotic pathway characterized by BAX upregulation and BCL2 downregulation. Conversely, siRNA-mediated knockdown of PRSS23 alleviated these inhibitory effects, promoting GC proliferation and survival. Conclusions: These findings establish PRSS23 as a pivotal pro-atretic factor in Wuding chickens, driving ovarian atrophy through the dual transcriptional-level inhibition of steroidogenesis and survival signaling pathways. This study identifies a potential molecular target for marker-assisted selection programs aimed at attenuating broodiness while preserving the superior meat quality traits of indigenous poultry. Full article

The Wuding chicken, a renowned indigenous breed in Yunnan Province, is prized for its superior meat quality; however, its economic potential is limited by pronounced broodiness and suboptimal egg production. Central to alleviating these constraints is the precise regulation of ovarian granulosa cell (GC) proliferation and steroidogenic processes that dictate follicular development and laying performance. While Estrogen Receptor 2 (ESR2) is a known transcription factor implicated in follicular maturation, its spatiotemporal dynamics within the hypothalamic-pituitary-ovarian (HPO) axis and its specific regulatory mechanisms in Wuding chicken remain elusive. This study characterizes ESR2 expression across the HPO axis during the laying and broody periods and functionally validates its role in GCs. We observed that ESR2 expression was significantly higher throughout the HPO axis during the laying period compared to the broody period, with the most pronounced differential expression occurring in the ovary. Notably, subcellular localization analysis revealed that ESR2 is distributed in both the nucleus and the cytoplasm, indicating involvement in both nuclear transcriptional regulation and cytoplasmic signaling. Functional assays demonstrated that ESR2 modulates the expression of genes associated with GC proliferation, steroidogenesis, and apoptosis, involving the PI3K/AKT/mTOR signaling pathway. Our findings indicate that this process involves a synergistic interplay between genomic and potential non-genomic actions. Specifically, ESR2 overexpression upregulates the expression of key signaling components and steroidogenic genes, including CYP19A1, STAR, PTGS2, and FSHR, while its cytoplasmic localization suggests a role in non‑genomic interactions. Together, these coordinated mechanisms synergistically maintain GC functional homeostasis. Collectively, these results prove that ESR2 plays an important role in regulating GC homeostasis and follicular development through genomic and non-genomic modes of action. These findings provide a molecular basis for the role of ESR2 in avian follicular development and offer potential targets for improving the reproductive efficiency of Wuding chickens. Full article

Broodiness in poultry represents a major bottleneck for reproductive performance, governed by complex remodeling of the hypothalamic-pituitary-ovarian (HPO) axis. CYP11A1, the rate-limiting enzyme in steroidogenesis, is essential for hormone synthesis; however, its spatiotemporal dynamics within the HPO axis during reproductive transitions remain unclear. Using the Wuding chicken as a model, this study characterized the expression profile and cellular function of CYP11A1. We identified a distinct “ovary-hypothalamus expression inversion” pattern: CYP11A1 expression exhibited an ovary-dominant pattern during the egg-laying period to support folliculogenesis; however, this shifted to a hypothalamus-dominant pattern during the broodiness period. This inversion indicates its active role in central neurosteroid modulation rather than a passive response to HPO axis regression. In vitro assays in granulosa cells (GCs) demonstrated that CYP11A1 overexpression significantly upregulated AKT1 and mTOR transcription, promoted the G0/G1 to S/G2/M cell cycle transition, and enhanced cell proliferation. Conversely, CYP11A1 knockdown arrested the cell cycle and suppressed the PI3K/AKT/mTOR pathway. Additionally, CYP11A1 coordinated the expression of steroidogenic genes (STAR, HSD3B1), reflecting a coupling between steroid metabolism and cell growth. These findings reveal CYP11A1 as a critical molecular node linking HPO axis remodeling, granulosa cell proliferation, and steroidogenesis, providing a potential target for molecular breeding to mitigate broodiness in indigenous chickens. Full article

Strong broodiness is an important reproductive characteristic of Magang geese, manifested by periodic laying–incubation activities during the breeding season. To investigate the changes in ovarian activity, follicular development, and gonadal reproductive regulators during the laying–incubation cycle, this study examined ovarian morphology, follicular development, blood reproductive hormones, and the expressions of reproductive regulators in the gonadal stroma, follicular granulosa, and membranous layer of the follicles during the laying, early broodiness, depth of broodiness, and end of broodiness periods of Magang geese. The results showed that ovarian activity degenerated and atrophied with the onset of brooding: the number of LWFs and SYFs decreased rapidly; LFY disappeared; PRL in the blood increased significantly; FSH, P4, E2, and INH decreased significantly; and the mRNA levels of GnIH and steroidogenic factors were up-regulated in the ovarian stroma. With the termination of brooding, the ovarian activity was gradually restored: the numbers of LWFs and SYFs increased gradually; LYF began to appear; PRL in the blood decreased; FSH and E2 increased; P4 remained low; and expressions of GnIH and steroidogenic factors were down-regulated in the ovarian stroma. During the laying period, with the rapid development of follicles, the expressions of FSHR and GnIH were significantly up-regulated; GnIH expression peaked in the SY granulosa layer, while FSHR expression peaked in the F6 granulosa layer. As LYF developed and ovulation occurred, the expressions of FSHR and GnIH were significantly down-regulated, LHR expression was significantly up-regulated, the expression of GnIHR peaked in the F3 granulosa layer and then declined, PRLR expression was the lowest in the F1 granulosa layer, steroidogenic factor StAR was up-regulated, CYP19A1 was down-regulated, and 3β-HSD peaked in the F3 granulosa layer and then declined. The results indicate that GnIH/GnIHR, FSHR, LHR, and PRLR in the gonad correspond to the upstream reproductive hormones and the jointly regulated steroid hormone production and follicular development, which leads to periodic changes in ovarian activity during the laying–incubation cycle of the breeding season of Magang geese. GnIH/GnIHR might play an important regulatory role for FSHR, LHR, and PRLR in the gonads. Full article

Background/Objectives: The Changshun green-shell laying hen with a strong broodiness is a Chinese indigenous chicken breed. Little is known about the mechanisms responsible for the ovary development of Changshun green-shell laying hens from the egg-laying period (LP) to the incubation period (BP). Methods: A total of six hens were selected from LP (n = three) and BP (n = three) at 28 weeks old. The RNA sequencing (RNA-seq) of ovaries from hens in LP and BP groups was performed to identify candidate genes and pathways associated with broodiness. Results: We identified 1650 differently expressed genes (DEGs), including 429 up-regulated and 1221 down-regulated DEGs, in chicken ovaries between LP and BP groups. Gene ontology term (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these DEGs were mainly involved in the pathways related to follicle development in chicken ovaries, including focal adhesion, the MAPK signaling pathway, and the FoxO signaling pathway, and vascular smooth muscle contraction, ECM–receptor interaction, and the GnRH signaling pathway were down-regulated in incubating ovaries. Eight candidate genes (EGFR, VEGFRKDRL, FLT1, KDR, PDGFRA, TEK, KIT and FGFR3) related to angiogenesis, folliculogenesis, steroidogenesis and oogenesis in ovaries were suggested to play important roles in the ovarian development of Changshun hens during the transition from LP to BP. Conclusions: This study identified a range of genes and several pathways that may be involved in regulating the broodiness of Changshun green-shell laying hens. These data are helpful to further enrich our understanding of the mechanism of incubation behaviour in chickens. Full article

Studies have demonstrated significant alterations in ovarian oxidative stress levels, ovarian degeneration, and follicular atresia during the broody period in geese. The results of this study showed that during the broody period, geese exhibited degraded ovarian tissues, disrupted follicular development, a thinner granulosa cell layer, and lower levels of ovarian hormones E2, P4, and AMH. Antioxidant activity (GSH, CAT, SOD, T-AOC, and the content of H₂O₂) and the mRNA expression levels of antioxidant genes (GPX, SOD-1, SOD-2, CAT, COX-2, and Hsp70) were significantly higher in pre-broody geese compared to laying geese, while the expression of apoptosis-related genes (p53, Caspase-3, and Caspase-9) increased and the anti-apoptotic gene Bcl-2 decreased. Additionally, proteomic analysis identified 703 differentially expressed proteins (DEPs), primarily concentrated in the GO categories of the biological process (biological regulation, response to stimulus, etc.) and enriched in the KEGG pathways (PI3K-Akt signaling pathway, etc.). Among them, XDH was central to the regulatory network. Furthermore, Western blotting revealed higher expression of XDH in the ovaries of pre-broody geese than those of laying geese. Pearson correlation analysis indicated a significant correlation between XDH expression and oxidative stress markers in the ovaries of geese (r > 0.75). Overall, these results demonstrated that geese experience ovarian atrophy and remarkably increased oxidative stress during the broody period, suggesting that XDH may be a key driver of broodiness in geese. Full article

Photoperiod can regulate the broodiness of geese and thus increase their egg-laying rate. The laying performance of geese is mainly determined by ovary and follicle development. To understand the effect of photoperiod on the ovary and small white follicles, sixteen 220-day-old healthy female Zhedong white geese were randomly divided into two groups for long photoperiods (15L:9D) and short photoperiods (9L:15D). The geese were euthanized after two months of feeding, and their ovaries and follicles were collected for transcriptome sequencing. RNA-seq analysis identified 187 and 448 differentially expressed genes in ovaries and small white follicles of different photoperiod groups, respectively. A long photoperiod promotes high expression of SPP1, C6, MZB1, GP1BA, and FCGBP genes in the ovaries, and increases the expression of SPP1, ANGPTL5, ALPL, ZP1, and CHRNA4 genes in small white follicles. Functional enrichment analysis showed that photoperiod could affect respiratory system development, smooth muscle cell proliferation in ovaries, and extracellular matrix-related function in small white follicles. WGCNA revealed 31 gene modules, of which 2 were significantly associated with ovarian weight and 17 with the number of small white follicles. Our results provide a better understanding of the molecular regulation in the photoperiod affecting goose reproduction. Full article

The aim of this study is to expose broiler embryos to species-specific sounds from the 444th and 468th hours of incubation until the end of incubation and, thus, to determine the effects of these stimulations on their hatching characteristics, performance traits, developmental stability, and behavioral characteristics. Auditory stimulation sounds are a total of 5 min of recording consisting of sounds made by embryos during and after internal piping and response sounds made by the broody hen at that time. The auditory stimulation pattern was created as 5 min of recording and 5 min of silence for a total of 20 min of recording, and this sound pattern was played continuously with 65 dB sound intensity and 800 Hz sound frequency. A total of 750 Ross 308 broiler hatching eggs were equally divided into three groups (AS1: auditory stimulation from hour 444, AS2: sound stimulation from hour 468), and two stimulation groups and a control (silent) group were incubated in three homologous incubators. Due to auditory stimulation, the hatching window in embryos exposed to species-specific sounds beginning at the 444th hour of the incubation period was determined to be 28 h in this study. Auditory stimulation was late in the embryos exposed to species-specific sounds from the 468th hour of incubation, and the incubation windows in this group and the silent (control) group were determined to be 36 h and 40 h, respectively. The chicks that were exposed to early auditory stimulation during incubation exhibited a higher average Tona score (99.03) in comparison to the other groups (p < 0.05). Additionally, the number of chicks discarded was comparatively higher than the others (p < 0.05). Auditory stimulation during incubation had no effect on live weight, Gompertz growth curve parameters, feed conversion ratio, slaughter-carcass characteristics, behavioral traits, or developmental balance characteristics. Consequently, it was determined that the incubation window and the number of marketable chicks were both substantially impacted by the implementation of species-specific auditory stimulation. However, further research is required to ascertain the precise timing of this auditory stimulation. Full article

Geese have strong brooding abilities, which severely affect their egg-laying performance. Phosphorylation is widely involved in regulating reproductive activities, but its role in goose brooding behavior is unclear. In this study, we investigated differences in the phosphoprotein composition of ovarian tissue between laying and brooding geese. Brooding geese exhibited ovarian and follicular atrophy, as well as significant oxidative stress and granulosa cell apoptosis. We identified 578 highly phosphorylated proteins and 281 lowly phosphorylated proteins, and a KEGG pathway analysis showed that these differentially phosphorylated proteins were mainly involved in cell apoptosis, adhesion junctions, and other signaling pathways related to goose brooding behavior. The extracellular regulated protein kinase (ERK)–B-Cell Lymphoma 2(BCL₂) signaling pathway was identified as playing an important role in regulating cell apoptosis. The phosphorylation levels of ERK proteins were significantly lower in brooding geese than in laying geese, and the expression of mitogen-activated protein kinase kinase (MEK) was downregulated. Overexpression of MEK led to a significant increase in ERK phosphorylation and BCL2 transcription in H₂O₂-induced granulosa cells (p < 0.05), partially rescuing cell death. Conversely, granulosa cells receiving MEK siRNA exhibited the opposite trend. In conclusion, geese experience significant oxidative stress and granulosa cell apoptosis during brooding, with downregulated MEK expression, decreased phosphorylation of ERK protein, and inhibited expression of BCL2. Full article

The goose is an economically important poultry species and was one of the first to be domesticated. However, studies on population genetic structures and domestication in goose are very limited. Here, we performed whole genome resequencing of geese from two wild ancestral populations, five Chinese domestic breeds, and four European domestic breeds. We found that Chinese domestic geese except Yili geese originated from a common ancestor and exhibited strong geographical distribution patterns and trait differentiation patterns, while the origin of European domestic geese was more complex, with two modern breeds having Chinese admixture. In both Chinese and European domestic geese, the identified selection signatures during domestication primarily involved the nervous system, immunity, and metabolism. Interestingly, genes related to vision, skeleton, and blood-O2 transport were also found to be under selection, indicating genetic adaptation to the captive environment. A forehead knob characterized by thickened skin and protruding bone is a unique trait of Chinese domestic geese. Interestingly, our population differentiation analysis followed by an extended genotype analysis in an additional population suggested that two intronic SNPs in EXT1, an osteochondroma-related gene, may plausibly be sites responsible for knob. Moreover, CSMD1 and LHCGR genes were found to be significantly associated with broodiness in Chinese domestic geese and European domestic geese, respectively. Our results have important implications for understanding the population structure and domestication of geese, and the selection signatures and variants identified in this study might be useful in genetic breeding for forehead knob and reproduction traits. Full article

The incubation behavior of geese seriously affects their egg production performance. Studies on incubation behavior have identified functional genes, but the regulatory architecture relationship between functional genes and chromatin accessibility remains poorly understood. Here, we present an integrated analysis of open chromatin profiles and transcriptome to identify the cis-regulatory element and their potential transcription factors involved in regulating incubation behavior in goose pituitary. Assay for transposase-accessible chromatin sequencing (ATAC-seq) revealed that open chromatin regions increased in the pituitary during the transition from incubation behavior to laying. We identified 920 significant differential accessible regions (DARs) in the pituitary. Compared to the laying stage, most DARs had higher chromatin accessibility in the brooding stage. Motif analysis of open DARs showed that the most significant transcription factor (TF) occupied sites predominantly enriched in motifs binding to the RFX family (RFX5, RFX2, and RFX1). While the majority of TF motifs enriched under sites of the nuclear receptor (NR) family (ARE, GRE, and PGR) in closed DARs at the incubation behavior stage. Footprint analysis indicated that the transcription factor RFX family exhibited higher binding on chromatin at the brooding stage. To further elucidate the effect of changes in chromatin accessibility on gene expression levels, a comparison of the transcriptome revealed 279 differentially expressed genes (DEGs). The transcriptome changes were associated with processes of steroid biosynthesis. By integrating ATAC-seq and RNA-seq, few DARs directly affect incubation behavior by regulating the transcription levels of genes. Five DAR-related DEGs were found to be closely related to maintaining the incubation behavior in geese. Footprinting analysis revealed a set of transcription factors (RFX1, RFX2, RFX3, RFX5, BHLHA15, SIX1, and DUX) which displayed the highest activity at the brooding stage. SREBF2 was predicted to be the unique differentially expressed transcription factor whose mRNA level was down-regulated and enriched in hyper-accessible regions of PRL in the broody stage. In the present study, we comprehensively profiled the transcriptome and chromatin accessibility in the pituitary related to incubation behavior. Our findings provided insight into the identification and analysis of regulatory elements in goose incubation behavior. The epigenetic alterations profiled here can help decipher the epigenetic mechanisms that contribute to the regulation of incubation behavior in birds. Full article

The broodiness traits of domestic geese are a bottleneck that prevents the rapid development of the goose industry. To reduce the broodiness of the Zhedong goose and thus improve it, this study hybridized it with the Zi goose, which has almost no broody behavior. Genome resequencing was performed for the purebred Zhedong goose, as well as the F2 and F3 hybrids. The results showed that the F1 hybrids displayed significant heterosis in growth traits, and their body weight was significantly greater than those of the other groups. The F2 hybrids showed significant heterosis in egg-laying traits, and the number of eggs laid was significantly greater than those of the other groups. A total of 7,979,421 single-nucleotide polymorphisms (SNPs) were obtained, and three SNPs were screened. Molecular docking results showed that SNP11 located in the gene NUDT9 altered the structure and affinity of the binding pocket. The results suggested that SNP11 is an SNP related to goose broodiness. In the future, we will use the cage breeding method to sample the same half-sib families to accurately identify SNP markers of growth and reproductive traits. Full article

Broodiness is an unfavorable trait associated with the cessation of egg laying. Studies have found that excessive granulosa cell apoptosis and autophagy occur during goose broodiness. Other studies have also confirmed that oxidative stress is an important cause of apoptosis and autophagy. However, whether oxidative stress occurs during goose broodiness and whether this oxidative stress causes apoptosis and autophagy have not been fully elucidated. In this study, we investigated the effects of oxidative stress on the autophagy and apoptosis of granulosa cells in broody geese. The results showed higher mRNA expression of genes related to antioxidative stress responses (GPX, SOD-1, SOD-2, COX-2, CAT and hsp70) in pre-broody and broody geese than in laying birds. In addition, increased levels of granulosa cell apoptosis and autophagy were observed in pre-broody geese than in laying geese. Additionally, granulosa cells treated with H₂O₂ exhibited increased apoptosis and autophagy in vitro, and these effects were responsible for goose granulosa cell death. Moreover, vitamin E treatment effectively protected granulosa cells from H₂O₂-induced oxidative stress by inhibiting ROS production. Correspondingly, granulosa cell apoptosis and autophagy were greatly alleviated by vitamin E treatment. Together, our results demonstrated serious oxidative stress and granulosa cell apoptosis and autophagy in broody geese, and oxidative stress promoted apoptosis and autophagy. Vitamin E alleviated the autophagy and apoptosis of granulosa cells by inhibiting oxidative stress. Full article