Transcriptomic analysis of muscle and adipose tissues identifies myokines and adipokines contributing to lipid deposition in Taoyuan Black pigs.

Meat quality and lean meat percentage are important to pig industry. Muscle and adipose tissues are regarded as secretory organs that release myokines and adipokines to mediate muscle-adipose tissue crosstalk, which regulates lipid deposition and skeletal muscle development. The Taoyuan Black (TB) pig, a Chinese indigenous breed, exhibits abundant lipid deposition and is known for excellent meat quality. The aim of this study was to explore the dynamics of muscle development and lipid deposition in TB pigs at different ages and to identify myokines and adipokines that contribute to lipid accumulation. Forty TB and 40 Duroc pigs were fed the same diet and slaughtered for analysis at age of 60, 120, 180, and 210 d. The "window phase" of lipid deposition in TB pigs was defined from 120 to 180 d of age according to carcass traits, intramuscular fat (IMF), and adipocyte area. Comparative transcriptome of the longissimus dorsi (LD) muscle and subcutaneous adipose revealed upregulated energy and lipid metabolism pathways in TB pigs at 180 d compared to 120 d (P < 0.05). Many myokines and adipokines associated with IMF and peripheral fat deposition have been identified via database comparison. Myokine IGF2 in TB pigs was downregulated at 180 d compared to 120 d (P < 0.05) and had negative correlation with backfat thickness, perirenal fat percentage, and fat percentage (P < 0.05), adipokines SFRP5 and AGT were upregulated in TB pigs at 180 d compared to 120 d and different between TB and Duroc pigs (P < 0.05). This study provides new insights into the interaction between muscle and adipose tissues, as well as potential targets for nutritional regulation of IMF, lean meat percentage, and meat quality.