Relationship of polymorphisms within metabolic genes and carcass traits in crossbred beef cattle

Feed intake has been shown to alter neurological signaling related to feeding behavior and subsequent activation of adipogenic mechanisms. Fat characteristics are pivotal for carcass and meat quality, including marbling score, flavor, and tenderness. The objective of this study was to establish the association of SNP, from genes functionally related to fat metabolism and obesity, with growth, fat, and carcass traits in steers. A total of 33 informative SNP from candidate genes [cocaine- and amphetamine-regulated transcript (CART), DNA-protein kinase (DNA-PK), fatty acid synthase (FASN), and fat mass and obesity associated (FTO)] were used to genotype crossbred steers (n = 620), and associations with growth and carcass traits were assessed. Five markers within the DNA-PK gene were associated (P < 0.05) with fat thickness. One of these SNP was also associated (P < 0.05) with percent choice, yield grade, and retail product yield. Additionally, 2 unique DNA-PK SNP were associated (P < 0.05) with marbling score. Three haplotypes were observed using these SNP and were significantly (P = 0.0014) associated with marbling score. Slaughter weight, ADG, and HCW were associated (P < 0.05) with SNP from CART, FTO, and FASN. Data from this study indicate that polymorphisms within candidate genes have an indirect relationship with lipogenesis. Replication of these results within other populations will be necessary to establish if these markers will be successful as predictors of fatness components and carcass traits in cattle.