Characterization of fatty acid compositions in longissimus thoracis muscle and identification of candidate gene and SNPs related to polyunsaturated fatty acid in Hu sheep.

In this study, 29 fatty acids (FAs) compositions and 8 FA groups were identified in 1,085 longissimus thoracis muscles of Hu sheep, and a significant correlation was observed among most FA traits. Transcriptomic analyses identified 412 differentially expressed genes (DEGs) between high polyunsaturated fatty acid (H-PUFA) and low PUFA (L-PUFA) groups. The functional enrichment analysis revealed that regulation of lipolysis in adipocytes, the AMPK signaling pathway, and the PPAR signaling pathway may play important roles in FA metabolism and biosynthesis. In general, PLIN1, LIPE, FABP4, LEP, ACACA, ADIPOQ, SCD, PCK2, FASN, PLIN2, LPL, FABP3, THRSP, and ACADVL may affect PUFA metabolism and lipid deposition. Four single nucleotide polymorphisms (SNPs) within PLIN2 were significantly associated with FA, especially SNP4 (g.7807 T>C) significantly correlated with C18:3n3, the combined genotype significantly associated with C18:3n3, C22:6n3, and n-6/n-3 PUFA. These results contribute to the knowledge of biological mechanisms and genetic markers involved in the FA composition of Hu sheep.