Abdominal fat deposition is an important trait in meat-producing ducks. F2 generations of 304 Cherry Valley and Runzhou Crested White ducks were studied to identify genes and lncRNAs affecting abdominal fat deposition. RNA sequencing was used to study abdominal fat tissue of four ducks each with high or low abdominal fat rates. In all, 336 upregulated and 297 downregulated mRNAs, and 95 upregulated and 119 downregulated lncRNAs were identified. Target gene prediction of differentially expressed lncRNAs identified 602 genes that were further subjected to Gene Ontology and KEGG pathway analysis. The target genes were enriched in pathways associated with fat synthesis and metabolism and participated in biological processes, including Linoleic acid metabolism, lipid storage, and fat cell differentiation, indicating that these lncRNAs play an important role in abdominal fat deposition. PPAPA, FOXO3, FASN, PNPLA2, FKBP5, TCF7L2, BMP2, FGF2, LIFR, ZBTB16, SIRT, GYG2, NCOR1, and NR3C1 were involved in the regulation of abdominal fat deposition. PNPLA2, TCF7L2, FGF2, LIFR, BMP2, FKBP5, GYG2, and ZBTB16 were regulated by the lncRNAs TCONS_00038080, TCONS_0033547, TCONS_00066773, XR_001190174.3, XR_003492471.1, XR_003493494.1, XR_001192142.3, XR_002405656.2, XR_002401822.2, XR_003497063.1, and so on. This study lays foundations for exploring molecular mechanisms underlying the regulation of abdominal fat deposition in ducks and provides a theoretical basis for breeding high-quality meat-producing ducks.

Fat deposition is an important factor affecting meat quality and feed conversion efficiency in meat ducks. This study aims to identify key circRNAs and genes affecting abdominal fat deposition. The correlations between abdominal fat and other growth performances were analyzed in 304 F₂ generation of Cherry Valley duck Runzhou Crested White ducks, and an RNA-seq analysis of abdominal fat tissues from ducks with high and low rates of abdominal fat was performed. Growth performance results showed that Abdominal fat ratio and Intramuscular fat were significantly higher in the high rates of abdominal fat (HF)group than in the low rates of abdominal fat (LF) group for ducks. RNA-seq analysis of abdominal fat tissue unveiled 85 upregulated and 72 downregulated circRNAs among the differentially expressed ones. Notably, 74 circRNAs displayed more than four-fold differential expression, constituting 47.13% of the differentially expressed genes. Functional enrichment analysis of the differentially expressed circRNA source and target genes indicated that 17 circRNAs might partake in regulating duck abdominal fat production by influencing pathways like PPAR signaling, lipid droplets, and triglyceride metabolism. Lastly, multiple circRNA-microRNA-messenger RNA interaction networks were constructed. The results of this study establish the groundwork for understanding the molecular mechanisms that regulate abdominal fat deposition in ducks, offering a theoretical reference for the selective breeding of high-quality meat-producing ducks.

Excessive deposition of abdominal fat will cause a waste of resources. In order to explore the key miRNAs and circRNA/lncRNA-miRNA-mRNA ceRNA regulatory network involved in regulating abdominal fat deposition, hematoxylin and eosin (H&E) staining was performed on abdominal fat tissues of ducks in the high abdominal fat rate group (HF) and low abdominal fat rate group (LF) at 21 and 42 days of age, and whole transcriptome sequencing was performed on abdominal tissues of ducks in the HF and LF groups at 42 days of age. The results showed that the number of adipocytes in ducks in the HF group was significantly higher than that in the LF group at 21 days of age (p < 0.001), while the number of adipocytes in ducks in the HF group at 42 days of age was significantly lower than that in the LF group (p < 0.001). In addition, transcriptome sequencing screened out a total of 14 differentially expressed miRNAs (10 miRNAs were significantly up-regulated, and 4 miRNAs were significantly down-regulated). By predicting the target genes of these differentially expressed miRNAs, a total of 305 target genes were obtained. Further analysis of miRNA target genes using GO and KEGG functional enrichment analyses revealed that these target genes were significantly enriched in the GnRH signaling pathway, the PPAR signaling pathway, insulin resistance, the mTOR signaling pathway, the AMPK signaling pathway, the FoxO signaling pathway, and other pathways related to adipose development. In addition, miRNA-205-x, miRNA-6529-x, miRNA-194-x, miRNA-215-x, miRNA-3074-x, miRNA-2954-x, novel-m0133-3p, and novel-m0156-5p were found to be important candidate miRNAs for abdominal fat deposition in ducks. These miRNAs were related to the expression of FOXO3, LIFR, Pdk4, PPARA, FBN1, MYH10, Cd44, PRELP, Esrrg, AKT3, and STC2. Based on these eight candidate miRNAs, a ceRNA regulatory network of circRNA/lncRNA-miRNA-mRNA regulating abdominal fat deposition was successfully constructed. The results of this study will provide a useful reference for accelerating the understanding of the molecular mechanism of duck abdominal fat deposition.

Abdominal fat deposition is an important economic trait in poultry, as excessive accumulation reduces feed efficiency and carcass yield. The gut microbiota is known to influence host energy metabolism and fat storage, suggesting its potential involvement in fat deposition. This study examined the relationship between intestinal microbiota and abdominal fat deposition in an F₂ population derived from Cherry Valley Ducks (♂) × Runzhou Crested White Ducks (♀) at 42 days of age. Based on abdominal fat rate, ducks with values of 0–0.75% and 1.5–2.25% were defined as the low (LF) and high (HF) abdominal fat groups, respectively. A combined multi-omics approach was used, including 16S rRNA gene sequencing, metagenomics, and whole transcriptomics, to compare high and low abdominal fat rate groups. 16S rRNA gene sequencing results showed that the cecum had the highest microbial diversity among all intestinal segments (duodenum, jejunum, ileum, and rectum) and was significantly enriched in carbohydrate metabolism pathways, highlighting its key role in nutrient utilization and growth. Therefore, the cecum was selected for further analysis. Metagenomic analysis of the cecum contents revealed significantly different intestinal microbial β diversity between the high and low abdominal fat rate groups (p < 0.05). The low abdominal fat rate group was enriched in beneficial microorganisms such as Paenibacillus, Butyrivibrio, Coprococcus, Ruminococcaceae, Veillonellaceae (Clostridiales), and Firmicutes. Conversely, the high abdominal fat rate group was characterized by an increased abundance of Bacteroidetes, including both beneficial and potentially pathogenic taxa such as Alistipes and Eggerthellales. The integrated analysis of metagenomic and whole transcriptome sequencing showed that Firmicutes and Bacteroidetes were not only related to energy metabolism, lipid metabolism, and amino acid metabolism, but also to the expression of FGF2, FKBP5, PNPLA2, PLIN3, FGFR2, DGAT2, and ACER2. In addition, Firmicutes and Bacteroidetes were also associated with 7 lncRNAs: XR_003493494.1, XR_003492471.1, XR_001190174.3, TCONS_00005095, XR_001190238.3, TCONS_00005095, and XR_003492841.1. In conclusion, this study highlights that the cecal microbiota is closely associated with abdominal fat deposition in ducks, elucidating its potential influence on host metabolism and gene expression. These findings enhance our understanding of the gut microbiota’s relationship with obesity and offer new strategies to modulate gut–microbe interactions to reduce abdominal fat accumulation in poultry.

Abdominal fat deposition is an important economic trait in meat ducks, but the molecular mechanisms underlying individual variation in abdominal fat rate remain unclear. In this study, abdominal fat traits were measured in 316 male Pekin ducks, from which six ducks with high abdominal fat rates and six ducks with low abdominal fat rates were selected for transcriptomic and metabolomic analyses of abdominal adipose tissue. Considerable individual variation in abdominal fat rate was observed in the population, providing a phenotypic basis for divergent group selection. Transcriptomic analysis identified 549 differentially expressed genes, including 181 upregulated and 368 downregulated genes in the LF group relative to the HF group. Functional enrichment analysis revealed that these genes were mainly involved in lipid metabolism, fatty acid metabolism, glycerolipid and glycerophospholipid metabolism, triglyceride metabolism, cholesterol metabolism, lipid transport, and the PI3K-Akt signaling pathway. Among the representative candidate genes, FASN, AGPAT1, ELOVL4, PEMT, PLTP, LCAT, LIPA, and LIPG were upregulated, whereas FABP5 and FABP6 were downregulated in the HF group relative to the LF group. Metabolomic analysis detected 222 differential metabolic features. The putatively annotated metabolites among these features were mainly associated with cholesterol metabolism, primary and secondary bile acid biosynthesis, bile secretion, steroid biosynthesis, alpha-linolenic acid metabolism, PPAR signaling, and adipocytokine signaling pathways. Integrated transcriptomic and metabolomic analysis further highlighted potential gene–metabolite modules related to lipid synthesis/remodeling, cholesterol–bile acid metabolism, and lipid signaling. Overall, these findings provide an exploratory molecular framework for subsequent validation of abdominal fat deposition in Pekin ducks. The proposed candidate genes and putatively annotated metabolites require validation in independent duck populations and further functional studies.

Excessive abdominal fat deposition reduces the meat yield and feed conversion efficiency of meat ducks. To identify circRNAs associated with this trait, this study performed circRNA sequencing on abdominal fat tissue from fat-type (HF) and lean-type (LF) Peking ducks. Among the 16,513 identified circRNAs, a total of 212 differentially expressed (DE) circRNAs were screened between the HF and LF groups. The host genes of the DEcircRNAs were enriched in processes such as glycerol metabolism, lipid storage, and lipolysis, and were involved in the AMPK, Wnt, insulin, and MAPK signaling pathways. RT-qPCR validated the expression differences of 7 candidate circRNAs and their host genes, of which 3 pairs showed co-variation and 4 pairs showed opposite changes. Based on a predictive ceRNA network comprising 33 circRNAs and 84 mRNAs, 4 candidate circRNAs were selected for validation at the cellular level. Oil Red O staining confirmed progressive lipid accumulation during the differentiation of primary preadipocytes. novel_circ_003710 and novel_circ_010207 were upregulated in both the HF group and differentiated cells, while novel_circ_013157 and novel_circ_011631 were downregulated. Time-course analysis revealed that novel_circ_003710 was consistently upregulated, novel_circ_010207 showed delayed upregulation, novel_circ_013157 was transiently downregulated, and novel_circ_011631 was consistently downregulated. This study identified DE circRNAs associated with abdominal fat deposition and the adipogenic differentiation of primary abdominal fat cells, providing candidate molecules for elucidating the post-transcriptional regulation of abdominal fat deposition in meat ducks.