Lipidomic analysis of Beijing-You chicken breast muscle during growth process reveals lipid changes and key lipid molecules associated with intramuscular fat

This study utilized high-throughput lipidomics to investigate the effects of age (90-150 days, 20-day intervals: D90, D110, D130, D150; 40 birds per age group) on intramuscular fat (IMF) deposition and lipid transformation in the breast muscle of Beijing-You chicken (BYC). A total of 1725 lipid molecules, predominantly categorized as glycerophospholipids (GP), glycerolipids (GL), and sphingolipids (SP), along with 53 lipid subclasses, were identified. Age-dependent IMF increase was mainly associated with triglyceride (TG), cardiolipin (CL) and phosphatidylglycerol (PG) accumulation. Additionally, based on the cutoff criteria of variable importance in projection (VIP) > 1, fold change (FC) > 1.1 or FC < 0.91, and p-value < 0.05, fifty-two lipids were further identified as differentially expressed lipid molecules (DELMs) between the three age pairwise-comparable groups (D110 vs D90, D130 vs D110, and D150 vs D130). Great variation in side fatty-acyl chains characteristics of DELMs, including saturation degree, average number of carbon atoms and double bonds, were observed within GL and GP due to age. TG(18:3/20:4/22:6), TG(22:5/18:2/22:6), and TG(16:0/22:6/22:6) were identified by Pearson correlation analysis as significantly positive correlates with IMF deposition, suggesting their potential as crucial biomarkers. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway topology analysis based on all 1725 detected lipid molecules indicated that lipid transformations were primarily involved in sphingolipid and glycerophospholipid metabolic pathways. In conclusion, this study used lipidomic analysis to clarify dynamic lipid changes, key lipid molecules (including three specific TG metabolites) and enriched metabolic pathways during BYC growth, providing insights into IMF-related lipid regulation and theoretical support for improving chicken meat quality.