Transcriptomic and Proteomic Analyses of the Liver and Ileum Identify Key Genes and Pathways Associated with Low and High Groups of Social Genetic Effect of Residual Feed Intake.

Social genetic effects (SGEs) refer to how the genotypes of other individuals impact an individual's phenotype within a population. These effects significantly influence the feeding behavior and production performance in pigs, though their mechanisms are not well understood. This study examined two pig groups with extreme SGE values for residual feed intake (RFI), analyzing their feeding behavior and the molecular mechanisms involved using transcriptomics and proteomics analysis of liver and ileum tissues. Pigs with higher SGE values exhibited distinct feeding patterns, spending more time at the feeder but making fewer visits. They consumed less overall feed but had a higher intake per visit. Differentially expressed genes and proteins were identified in the liver and ileum and were associated with processes such as mitochondrial functions, oxidative phosphorylation, and cholesterol metabolism. Integrated analysis supported these findings. Combined transcriptome and proteome analysis identified potential key genes that were associated with processes including mitochondrial processes, oxidative phosphorylation, fat digestion and absorption, and cholesterol metabolism. The results showed that pigs with differing SGE values display different feeding behaviors and utilize distinct molecular pathways affecting RFI. These findings offer valuable insights into how SGEs influence feed efficiency and shed light on the fundamental mechanisms underlying it.