PSXV-2 - Genome-wide Association and Gene Network Analysis of Fatty Acid Composition in Beef from Brangus Cattle

Abstract: Beef is high in key nutrients; however, it is often perceived as unhealthy because of its high fat content, particularly its saturated fat. The fat content of beef is controlled by multiple genetic factors and impacts meat quality traits. The objectives of this study were to 1) characterize the natural variation in fatty acid (FA) composition of Bos taurus indicus influenced beef cattle, 2) estimate phenotypic and genetic correlations of FA composition with carcass and meat quality traits, 3) use genome-wide association (GWAS) to identify genes with the greatest effect on FA composition, and 4) use gene network analysis to identify genes with small effects on FA content. The following traits were recorded on 1,066 Brangus steer: carcass weight (kg; 373 ± 36.3); marbling (436 ± 84.2); quality grade; back fat (cm; 1.6 ± 0.6); ribeye area (cm²; 83.3 ± 9.5); yield grade (3.2 ± 0.9); Warner-Bratzler shear force (kg; 5.1 ± 1.0); and 27 FA [saturated (%; 47.6 ± 3.1), monounsaturated (%; 46.3 ± 3.5), and polyunsaturated (%; 6.1 ± 2.0)]. Carcass traits had weak beneficial correlations to FA composition suggesting the possibility to manage or select for beef with less saturated fat without negatively impacting meat quality. GWAS identified four QTL and gene network analysis identified 177 genes related to lipid storage, transportation, and modification.