Expression of Genes Related to Lipid Metabolism in Adipose Tissue of Mid-lactation Dehong Dairy Buffalo and Its Relationship with Milk Fat Percentage

Purpose To investigate the relationship between the expression of lipid metabolism-related genes in adipose tissue and milk fat percentage in Dehong dairy buffalo.

Methods Dehong dairy buffaloes were classified into a high milk fat percentage group (Group H) and a low milk fat percentage group (Group L) based on their milk fat percentage. Three buffaloes from each group were randomly selected and slaughtered to collect subcutaneous adipose tissue for total RNA extraction. The expression levels of genes related to lipid synthesis, transport, transcriptional regulation, and catabolism were determined using real-time quantitative PCR, and analyzed for correlation with milk fat percentage. Additionally, a protein-protein interaction (PPI) network was constructed to identify key gene targets regulating milk fat synthesis.

Results In Group H, the expression levels of most genes involved in lipid synthesis, transport, and transcriptional regulation (such as FASN, FABP3, VLDLR, AGPAT2, PPARγ, and so on) and the gene related to fatty acid β-oxidation CPT1A were significantly lower than those in Group L (P<0.05); the expression levels of lipolysis-related genes (ATGL and HSL) were significantly higher than those in Group L (P<0.05). Correlation analysis showed that genes involved in lipid synthesis, transport, and regulation (such as FASN, FATP1, PLIN1, SCD, and so on) were significantly or extremely significantly negatively correlated with milk fat percentage (P<0.05 or P<0.01), whereas lipolysis genes (ATGL and HSL) were significantly or extremely significantly positively correlated with milk fat percentage (P<0.05 or P<0.01). PPI network analysis suggested that SCD, PPARγ, FASN, and GPAT1 might be key hub genes regulating lipid metabolism.

Conclusion There are significant differences in the expression of lipid metabolism genes in the adipose tissue of Dehong dairy buffaloes with different milk fat percentages. Low expression of genes related to lipid synthesis and transport, and high expression of genes related to lipolysis may be conducive to fat mobilization, providing substrates for mammary synthesis of milk fat, which may be an important metabolic basis for the high milk fat characteristics of Dehong dairy buffalo.