Coordinated liver-serum-adipose lipid alterations and hepatic proteins regulate tissue-specific deposition of intramuscular and abdominal fat in chickens

In broiler production, achieving tissue-specific deposition of intramuscular fat (IMF) and abdominal fat (AF) remains challenging because the regulatory mechanisms are not fully understood. In this study, we focused on the liver, a shared hub of lipid metabolism for IMF and AF, and integrated targeted lipidomics and proteomics to characterize coordinated liver-serum-adipose lipid alterations and identify key hepatic regulatory proteins. The results showed that both IMF and AF deposition were primarily characterized by increased lipids from the triacylglycerol (TAG) subclass, and hepatic lipids responding to adipose tissue growth were predominantly from the TAG and diacylglycerol subclasses. In contrast, in the liver-serum-IMF alterations, serum lipid changes were mainly assigned to the glycerophospholipid class, whereas those in the liver-serum-AF alterations were primarily associated with the TAG subclass. In addition, serum glucose and 45 hepatic proteins were identified as potential regulators underlying the tissue-specific deposition of IMF and AF, including CA13, RCJMB04_17b10, SDE2, and the secreted protein C8G. These findings provide new insights into the coordinated regulation of body fat distribution by hepatic lipids and proteins, and offer a theoretical basis for molecular marker-assisted breeding of high-quality broilers with high IMF and low AF deposition.