Muscle transcriptomic profiles in pigs with divergent phenotypes for fatness traits

Area of Science:

• Animal Genetics and Breeding
• Nutritional Genomics
• Metabolic Regulation

Background:

• Increasing intramuscular fat (IMF) in pigs enhances meat quality but may affect muscle metabolism.
• Duroc pigs, with high IMF aptitude, serve as a model for studying muscle lipid metabolism.
• Understanding muscle lipid metabolism in pigs has implications for human metabolic diseases like obesity.

Purpose of the Study:

• To investigate the transcriptomic profiles of Duroc pigs with divergent fatness phenotypes.
• To analyze the impact of selection for high IMF on muscle lipid and carbohydrate metabolism.
• To explore the genetic basis of muscle lipid metabolism relevant to human metabolic health.

Main Methods:

• Analysis of muscle gene expression profiles using microarray and quantitative PCR.
• Comparison of transcriptomic data between Duroc pigs with extreme phenotypes for lipid traits (HIGH vs. LOW groups).
• Determination of divergent phenotypes for 13 fatness traits in 68 Duroc pigs.

Main Results:

• Genes involved in fatty acid uptake, lipogenesis, and triacylglycerol synthesis were upregulated in HIGH IMF pigs.
• Upregulation of lipolytic genes alongside synthesis genes suggests a continuous triacylglycerol turnover cycle.
• Genes in the insulin-signaling pathway were upregulated, while antigen-processing genes were downregulated in HIGH IMF pigs.

Conclusions:

• Selection for increased IMF in pigs results in a metabolic shift, not a disruption, of muscle homeostasis.
• Further research is needed on post-translational modifications and protein localization to fully understand lipid deposition effects.
• This study provides a foundation for elucidating the genetic basis of metabolic diseases through pig models.