Growing evidence has shown the involvement of the gut–liver axis in lipogenesis and fat deposition. However, how the gut crosstalk with the liver and the potential role of gut–liver crosstalk in the lipogenesis of chicken remains largely unknown. In this study, to identify gut–liver crosstalks involved in regulating the lipogenesis of chicken, we first established an HFD-induced obese chicken model. Using this model, we detected the changes in the metabolic profiles of the cecum and liver in response to the HFD-induced excessive lipogenesis using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) analysis. The changes in the gene expression profiles of the liver were examined by RNA sequencing. The potential gut–liver crosstalks were identified by the correlation analysis of key metabolites and genes. The results showed that a total of 113 and 73 differentially abundant metabolites (DAMs) between NFD and HFD groups were identified in the chicken cecum and liver, respectively. Eleven DAMs overlayed between the two comparisons, in which ten DAMs showed consistent abundance trends in the cecum and liver after HFD feeding, suggesting their potential as signaling molecules between the gut and liver. RNA sequencing identified 271 differentially expressed genes (DEGs) in the liver of chickens fed with NFD vs. HFD. Thirty-five DEGs were involved in the lipid metabolic process, which might be candidate genes regulating the lipogenesis of chicken. Correlation analysis indicated that 5-hydroxyisourate, alpha-linolenic acid, bovinic acid, linoleic acid, and trans-2-octenoic acid might be transported from gut to liver, and thereby up-regulate the expression of ACSS2, PCSK9, and CYP2C18 and down-regulate one or more genes of CDS1, ST8SIA6, LOC415787, MOGAT1, PLIN1, LOC423719, and EDN2 in the liver to enhance the lipogenesis of chicken. Moreover, taurocholic acid might be transported from the gut to the liver and contribute to HFD-induced lipogenesis by regulating the expression of ACACA, FASN, AACS, and LPL in the liver. Our findings contribute to a better understanding of gut–liver crosstalks and their potential roles in regulating chicken lipogenesis.

The growth and development of skeletal muscle determine the productivity of pigeon meat production, and miRNA plays an important role in the growth and development of this type of muscle. However, there are few reports regarding miRNA regulating the growth and development of skeletal muscle in pigeons. To explore the function of miRNA in regulating the growth and development of pigeon skeletal muscle, we used RNA sequencing technology to study the transcriptome of pigeons at two embryonic stages (E8 and E13) and two growth stages (D1 and D10). A total of 32,527 mRNAs were identified in pigeon skeletal muscles, including 14,378 novel mRNAs and 18,149 known mRNAs. A total of 2362 miRNAs were identified, including 1758 known miRNAs and 624 novel miRNAs. In total, 839 differentially expressed miRNAs (DEmiRNAs) and 11,311 differentially expressed mRNAs (DEGs) were identified. STEM clustering analysis assigned DEmiRNAs to 20 profiles, of which 7 were significantly enriched (p-value < 0.05). These seven significantly enriched profiles can be classified into two categories. The first category represents DEmiRNAs continuously downregulated from the developmental stage to the growth stage of pigeon skeletal muscle, and the second category represents DEmiRNAs with low expression at the development and early growth stage, and significant upregulation at the high growth stage. We then constructed an miRNA–mRNA network based on target relationships between DEmiRNAs and DEGs belonging to the seven significantly enriched profiles. Based on the connectivity degree, 20 hub miRNAs responsible for pigeon skeletal muscle development and growth were identified, including cli-miR-20b-5p, miR-130-y, cli-miR-106-5p, cli-miR-181b-5p, miR-1-z, cli-miR-1a-3p, miR-23-y, cli-miR-30d-5p, miR-1-y, etc. The hub miRNAs involved in the miRNA–mRNA regulatory networks and their expression patterns during the development and growth of pigeon skeletal muscle were visualized. GO and KEGG enrichment analysis found potential biological processes and pathways related to muscle growth and development. Our findings expand the knowledge of miRNA expression in pigeons and provide a database for further investigation of the miRNA–mRNA regulatory mechanism underlying pigeon skeletal muscle development and growth.

Fat volume and obesity-related genes (e.g., the FTO gene) are important candidate genes affecting energy metabolism. Single nucleotide polymorphisms (SNPs) in the FTO gene are associated with carcass, growth and meat quality traits of pigs, cattle, sheep, rabbits and ducks. The purpose of this study was to detect the single nucleotide polymorphisms in the chicken FTO gene coding region by DNA sequencing and analyze its association with the carcass and growth traits of Heying black chickens. We detected polymorphisms in exons 5, 7, 8 and 9, respectively, g.57337C>A, g.64757T>G, g.97213G>A and g.220985G>A, which are synonymous mutations. g.57337C>A mutation site CA and AA genotype individuals were significantly higher than CC genotype individuals in live weights, head weights, breast muscle weights and leg muscle weights (p < 0.05), AA genotype individuals were significantly higher than CC genotype individuals in slaughter live weights and liver weights (p < 0.05) and CA and AA genotype individuals were significantly higher than CC genotype individuals in heart weights (p < 0.01). In terms of growth traits, the weights of individuals with genotype CA at 8 weeks were significantly higher than that of individuals with genotype CC (p < 0.05), and the weights of individuals with genotype AA and CA at 10 weeks and 16 weeks were significantly higher than that of individuals with genotype CC (p < 0.05). For the g.64757T > G mutation, individuals with the TT genotype exhibited significantly higher values (p < 0.05) than those with the TG genotype across multiple traits, including slaughter weight, live weight, eviscerated weight and semi-eviscerated weight. Individuals with GG genotypes were significantly higher than individuals with TG genotypes (p < 0.05) in slaughter weights and wing weights. In terms of growth traits, the 16-week-old body weight of individuals with TT genotype was significantly higher than that of individuals with TG genotype (p < 0.01). The GA genotype exhibited significantly higher slaughter weights in the g.97213G>A variant compared to the GG genotype (p < 0.01), and in live weights, eviscerated weights, semi-eviscerated weights, leg muscle weights and wing weights, GA genotype was significantly higher than in GG genotype (p < 0.05). In terms of growth traits, GA genotype was significantly higher in individuals 8 weeks old, 10 weeks old and 16 weeks old than GG genotype (p < 0.05). g.220985G>A was significantly higher in individuals with GG genotype than GA genotype (p < 0.05). In terms of growth traits, the weight of GG genotype was significantly higher than that of GA genotype (p < 0.05). The results showed that the FTO gene may be a candidate gene related to chicken growth and slaughter traits and lays a foundation for Heying black chicken assisted breeding.

Intercellular communication is crucial for the coordination of skeletal muscle development. However, the intricate signaling networks that regulate chicken myogenesis are not yet fully elucidated. In this study, we utilized CellChat analysis on single-cell and single-nucleus RNA sequencing data to systematically delineate cell–cell communication patterns across five critical developmental stages of chicken skeletal muscle: embryonic day 4 (E4), day 6 (E6), day 12 (E12), day 18 (E18), and post-hatch day 30 (P30). Our findings indicate that communication architectures are highly stage-specific, with mesenchymal cells acting as the predominant signaling hub during the early embryonic stages (E4–E6), whereas fibro-adipogenic progenitors become the principal communicators during mid-to-late embryogenesis (E12–E18). At E4, the communication network was relatively simple, comprising 51 ligand–receptor pairs primarily involving the neural cell adhesion molecule, slit guidance ligand, and midkine (MK) signaling pathways between myogenic progenitors and mesenchymal cells. By E6, the network had expanded significantly, encompassing 6237 ligand–receptor pairs across 51 signaling pathways, which coincided with the emergence of multiple myogenic lineages. Peak communication complexity was observed at E12, characterized by 11,675 ligand–receptor pairs and 61 signaling pathways, reflecting the secondary wave of myogenesis. Comparative analysis across developmental stages revealed key signaling transitions: the pleiotrophin and MK pathways were predominantly active during the early phase of myogenic commitment (E4–E6), whereas the collagen, laminin, and adhesion G protein-coupled receptor L pathways were more prominent during the secondary myogenesis phase (E6–E12). Notably, a significant shift in communication patterns was observed from E12 to E18, marked by a reduction in developmental pathway signaling and an increase in immune-related communications. By P30, the communication network had stabilized into a homeostatic state, centered on interactions among myofibers, stromal cells, and the vascular system. This comprehensive atlas of intercellular communication offers novel insights into the signaling dynamics underpinning chicken skeletal muscle development.