CircRNA Profiling Identifies Candidates Associated with Abdominal Fat Deposition in Ducks

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.