Activation of the RAS/PPARα pathway reduces backfat deposition of Gayal (Bos frontalis)

Backfat deposition is a pivotal economic trait that profoundly affects the quality and production efficiency of beef products in the beef industry. Gayal, as a unique bovine species,primarily found in the high-altitude regions of southwestern China, which provides highly nutritious meat to the local tribal population. However, the intrinsic molecular regulatory mechanisms underlying its backfat deposition remain largely unclear. The present study was designed to compare the differences in backfat deposition traits between Gayal and local cattle, and further elucidate the potential regulatory mechanisms underlying these differences.

The results shown that Gayal had smaller adipocyte area, fewer number of adipocytes per unit area, and decreased concentration of triglyceride in backfat (P < 0.05). Backfat transcriptome profile exhibited that 875 DEGs (434 up- and 441 down-regulated genes) were obtained between the Gayal and local cattle. Enrichment analysis showed that PPAR signaling pathway (ko03320), renin-angiotensin system (RAS, ko04614), fatty acid metabolic process (GO:0006631), monocarboxylic acid metabolic process (GO:0032787), unsaturated fatty acid metabolic process (GO:0033559), fatty acid oxidation (GO:0019395), and lipid oxidation (GO:0034440) were enriched in the Gayal based on Kyoto Encyclopedia of Genes and Genomes and Gene Ontology (GO). We inspected critical regulators of RAS pathway and found higher level of ACE (P < 0.05), Ang1-7 (0.05 < P < 0.1), and lower level of AngI (P < 0.01) were observed in backfat of Gayal. The phosphorylation level of PPARα was significantly higher in backfat of Gayal (P < 0.05).

These findings suggest that reduced backfat deposition in Gayal is associated with gene expression of the RAS/PPARα pathway. Integrated analysis supports a model wherein the Ang1-7-MAS axis may enhance PPARα signaling, thereby promoting fatty acid β-oxidation and limiting fat accumulation. This study provides novel insights into the physiological mechanisms of backfat deposition and offers potential targets for genetic breeding strategies in cattle.