A research team led by Prof. YIN Yulong from the Institute of Subtropical Agriculture of the Chinese Academy of Sciences has investigated the metabolic difference of longissimus dorsi muscle between Taoyuan black pigs and Duroc pigs at different ages. Their study reveals the mechanisms of interaction between muscle and adipose tissue, mediated by muscle-derived secretory metabolites.

Muscle and adipose tissues are two crucial metabolic and secretory organs that communicate through secretory factors, forming what is known as the "muscle-adipose axis." These secretory metabolites serve as important mediators of crosstalk between muscle and adipose tissue, regulating muscle differentiation, metabolic homeostasis, and lipid deposition.

Compared to the lean Duroc pig, the Taoyuan black pig—a Chinese native breed from Taoyuan County—has a higher intramuscular fat content, a greater proportion of slow myofibers, superior meat quality, and more extensive peripheral fat deposition. This breed has significant economic value in regulating lipid deposition.

Additionally, leveraging Chinese native pig resources is vital for revitalizing the seed industry. Both Taoyuan black and Duroc pigs serve as ideal animal models for studying the mechanisms of muscle-adipose tissue interaction and metabolic diseases.

Published in SCIENCE CHINA Life Sciences on Jan 10, the researchers conducted non-targeted metabolomics analysis of longissimus dorsi muscle at different ages, combined with data on lipid deposition phenotypes.

They identified the age range of 120 to 180 days as a critical "window period" for lipid deposition and meat quality development in Taoyuan black pigs. Integrated metabolome and transcriptome analysis revealed that the metabolic differences in the longissimus dorsi muscle between breeds and ages mainly reflected in pathways related to energy, lipid, amino acid and protein metabolism.

The study subsequently identified dozens of specific metabolites in longissimus dorsi muscle of Taoyuan black pigs at 180 days of age. Using sub-localization information from the HMDB database, the researchers identified differentially secreted metabolites significantly related to intramuscular fat content.

Notably, organic acid metabolites (fumaric acid, succinic acid, malic acid, gamma-aminobutyric acid) and certain amino acid and peptide metabolites (L-glutamic acid, L-lysine) exhibited a significant negative correlation with intramuscular fat. In contrast, lipid metabolites (2-hydroxyisovaleric acid, carnitine) showed a significant positive correlation with intramuscular fat content.

By focusing on the metabolites that mediate muscle-adipose tissue interaction, this study systematically analyzed the differences in muscle metabolism between obese and lean pigs. The findings provide potential dietary additives and intervention targets for the nutritional regulation of lipid deposition and pork quality, as well as theoretical references for studying metabolic diseases using pigs as animal models.

Integrated metabolome and transcriptome analysis (Image by GUO Liu)

Differential metabolites and genes between breeds and ages (Image by GUO Liu)

Correlation between muscle-derived differentially secretory metabolites and intramuscular fat (Image by GUO Liu)