The gut microbiota plays a critical role in the growth, development, nutritional digestion, and overall health of chickens. Furthermore, certain probiotics isolated from poultry intestines have demonstrated the potential to enhance immune function and production performance in chickens. To investigate the differences in gut microbiota among chickens from various geographical environments and different breeds of broiler and laying hens, we conducted 16S rRNA sequencing on the fecal microbiota of 140 Chinese native chickens and ten Roman layers. In addition, we isolated and screened the potential probiotics to examine their biological characteristics, genome profiles, and functionality in animals. Our findings revealed the significant variations in gut microbiota composition and structure between Tibetan chickens (ZJ), which reside in high-altitude regions, and Meihua chickens (MH) and Xuhai chickens (XH), which inhabit low-altitude regions. Specifically, Cupriavidus and Candidatus_Bacilloplasma were identified as unique microbial communities in high and low altitudes, respectively. Notably, among regions with similar altitudes, Luning chickens (LN) exhibited the lowest α diversity, accompanied by a remarkably high relative abundance of Firmicutes and Lactobacillus. Conversely, Wugu chickens (WGs) and Yaoshan chickens (YSs) displayed similar gut microbiota profiles. Furthermore, distinctive gut microbiota patterns were observed between the different breeds of broilers and laying hens. Commercial Roman layers (LMs) exhibited significantly lower alpha diversity compared to native chickens, and broilers and laying hens predominantly harbored Firmicutes, Bacteroidota, and Proteobacteria. Of particular interest, the probiotics Lactobacillus agilis MH1 and Lactobacillus salivarius ZJ1, derived from chicken feces, exhibited favorable genomic profiles, and demonstrated anti-colitis effects and immunomodulatory functions. These findings provide a crucial theoretical foundation for native chicken research and offer insights for the future development and formulation of chicken-derived probiotics.

Objective: Spermatozoa are produced within the seminiferous tubules after sexual maturity. The expression levels of mRNAs and lncRNAs in testicular tissues are different at each stage of testicular development and are closely related to formation of the extracellular matrix (ECM) and spermatogenesis. Therefore, we set out to study the expression of lncRNAs and mRNAs during the different developmental stages of the goat testis.Methods: We constructed 12 RNA libraries using testicular tissues from goats aged 3, 6, and 12 months, and studied the functions of mRNAs and lncRNAs using the gene ontogeny (GO) and Kyoto encyclopedia of genes and genomes (KEGG) databases. Relationships between differentially expressed genes (DEGs) were analyzed by lncRNA-mRNA coexpression network and protein-protein interaction network (PPI). Finally, the protein expression levels of matrix metalloproteinase 2 (MMP2), insulin-like growth factor 2 (IGF2), and insulin-like growth factor-binding protein 6 (IGFBP6) were detected by western blotting.Results: We found 23, 8, and 135 differentially expressed lncRNAs and 161, 12, and 665 differentially expressed mRNAs that were identified between 3 vs 6, 6 vs 12, and 3 vs 12 months, respectively. GO, KEGG, and PPI analyses showed that the differential genes were mainly related to the ECM. Moreover, MMP2 was a hub gene and co-expressed with the lncRNA TCONS-0002139 and TCONS-00093342. The results of quantitative reverse-transcription polymerase chain reaction verification were consistent with those of RNA-seq sequencing. The expression trends of MMP2, IGF2, and IGFBP6 protein were the same as that of mRNA, which all decreased with age. IGF2 and MMP2 were significantly different in the 3 vs 6-month-old group (p<0.05).Conclusion: These results improve our understanding of the molecular mechanisms involved in sexual maturation of the goat testis.

Puan Panjiang black-bone chickens are renowned for their distinctive traits, deep black coloration, and high-quality protein content, making them a focus of genetic research due to their unique egg-laying abilities. In this study, 110 Puan Panjiang black-bone chickens were used to investigate the effects of natural and artificial selection influencing egg production. Whole-genome resequencing data from red junglefowl (RJF) and high-egg-production (HEP) and low-egg-production (LEP) groups of Puan Panjiang black-bone chickens revealed significant genetic variants associated with egg production traits. Additionally, transcriptome analysis of 47 samples from ovary stroma, small white follicles (SWFs), small yellow follicles (SYFs), and liver tissues from 6 HEP and 6 LEP groups identified differentially expressed genes. Notably, differences in egg production were linked to small yellow follicles rather than ovary stroma or SWFs. Key candidate genes, including TRIM7, CASR, SPTBN5, GAL1, ZP1, IL4I1, and CCL19, were identified as potential contributors to egg-laying performance. This study underscores the genetic diversity within this breed and provides valuable insights for future breeding programs to enhance egg production, supporting the sustainable development of this local resource.

Background/Objectives: Eggshell quality is a critical factor influencing consumer preference and the economic benefits of poultry enterprises, and the uterus is the key site for eggshell synthesis. Yaoshan chicken (YS), an indigenous chicken breed in China, is renowned for its flavorful meat and high-quality eggs. However, its egg production is lower compared to specialized strains. Therefore, the GYR crossbreed was developed by three-line hybridization for YS chicken, which can produce green-shelled eggs with better eggshell thickness and strength than YS chicken (p < 0.01). To explore the molecular mechanisms underlying the differences in eggshell quality between GYR and YS chickens, we conducted an integrated transcriptomic and metabolomic analysis. Methods: Twelve uterus samples (six from GYR and six from YS chickens) were collected during the period of eggshell calcification at 260 days of age. RNA sequencing (RNA-seq) and liquid chromatography–mass spectrometry (LC-MS/MS) were performed to identify differentially expressed genes (DEGs) and differential metabolites (DMs), respectively. Results: A total of 877 DEGs were identified in the GYR group, including 196 upregulated and 681 downregulated genes (|log₂ (fold change)| > 1, p-value < 0.05). Additionally, 79 DMs were detected, comprising 50 upregulated and 29 downregulated metabolites (|log₂ (fold change)| > 1, VIP > 1). Notably, the key DEGs (SLCO1B3, SLCO1B1, PTGR1, LGR6, MELTF, CRISP2, GVINP1, and OVSTL), important DMs (prostaglandin-related DMs and biliverdin) and signaling pathways (calcium signaling, neuroactive ligand–receptor interaction, arachidonic acid metabolism, bile secretion, and primary bile acid biosynthesis) were major regulators of the eggshell quality. Furthermore, an integrated transcriptomic and metabolomic analysis revealed two significant gene–metabolite pairs associated with eggshell quality: PTGDS–prostaglandin E2 and PTGS1–prostaglandin E2. Conclusions: This study provides a theoretical foundation for the improved eggshell quality of Yaoshan chicken.

Introduction: Polydactyly—the presence of extra digits—is a heritable limb anomaly observed in several chicken breeds. The Puan Panjiang black-bone chicken uniquely exhibits both four- and five-toed phenotypes, yet the genetic and transcriptional bases of this trait remain unclear. This study aimed to elucidate the genomic variants and gene expression changes underlying polydactyly in this breed.Methods: We performed whole-genome resequencing (WGS) on 43 Puan Panjiang chickens (22 four-toed, 21 five-toed) and integrated publicly available data from 17 red junglefowl (RJF). After stringent quality filtering, we aligned reads to GRCg7b, identified high-confidence SNPs and InDels, and conducted sliding-window analyses of nucleotide diversity (θπ) and genetic differentiation (F ST) to detect selective sweeps. Concurrently, we carried out RNA-seq on embryonic foot tissues at days 6–9 (24 four-toed, 24 five-toed samples), quantified transcript levels (TPM), and identified differentially expressed genes (DEGs) with DESeq2 (adjusted P < 0.01, |log₂FC|> 2). Fuzzy c-means clustering delineated temporal expression patterns, and enrichment analyses (KEGG, GO) characterized candidate pathways.Results: Genomic scans revealed 1,339 and 1,035 positively selected genes in five-toed and four-toed chickens, respectively, with 335 shared loci relative to RJF. Top candidates in polydactylous birds included AUH, SEMA4D, and ROR2, while four-toed birds showed strong signals at RYR2, KITLG, and PGR. KEGG enrichment highlighted the MAPK signaling pathway in both groups, and uniquely in five-toed birds, lipid metabolism and vascular signaling pathways (e.g., sphingolipid and apelin signaling). Transcriptome profiling demonstrated that the greatest transcriptional divergence between phenotypes occurred at embryonic Days 8–9, pinpointing a critical window for extra-digit differentiation. Clustering analyses indicated coordinated regulation of genes involved in ribosome biogenesis, extracellular matrix organization, and muscle development across stages.Discussion: Our integrated analyses pinpoint MAPK pathway genes and lipid-vascular interactions as central to extra-toe formation, with the Days 8–9 embryonic window being pivotal. These findings offer clear targets for functional validation and may guide selective breeding for limb traits in poultry.

Fasting-induced molting is widely employed in the poultry industry to rejuvenate the reproductive system of aging laying hens, thereby improving post-molt laying performance and extending productive lifespan. However, substantial individual variation in post-molt reproductive recovery may compromise the overall effectiveness of molting programs. Elucidating the molecular basis underlying this variation is therefore important for poultry production and genetic improvement. In this study, laying hens were classified into high-recovery (HR) and low-recovery (LR) groups according to their egg production recovery following fasting-induced molting. Transcriptomic profiling of the hypothalamus, pituitary, ovary, and liver was performed using RNA sequencing (RNA-seq). A total of 271, 435, 3,425, and 289 differentially expressed genes (DEGs) were identified between the HR and LR groups in the hypothalamus, pituitary, ovary, and liver, respectively. Functional enrichment analysis showed that these DEGs were primarily associated with protein homeostasis, hormone response, ribosome function, and immune regulation, indicating distinct tissue-specific biological functions during post-molt recovery. Integration of weighted gene co-expression network analysis (WGCNA) and protein-protein interaction (PPI) network analysis further identified HSP90AA1, GDF7, CTSS, and STS as candidate hub genes associated with post-molt reproductive recovery. Collectively, this study provides a comprehensive multi-tissue transcriptomic landscape of post-molt egg production recovery and identifies key biological processes and candidate genes potentially involved in this process. These findings improve our understanding of the molecular mechanisms underlying post-molt reproductive recovery and provide valuable genetic resources for the genetic improvement of laying hens with superior post-molt performance.