Abstract
Fatty acid composition has become recognized as an important trait in beef because of its relationship with beef quality, including beef flavor and tenderness. Our laboratory attempted to identify genes responsible for the fatty acid composition of cattle. We found several such genes and developed genetic markers of fatty acid composition. The findings were as follows. 1) Genetic polymorphisms of the stearoyl-CoA desaturase (SCD) gene are associated with fatty acid composition. The effects of SCD type A gene substitution on the percentage of monounsaturated fatty acid (MUFA) and the melting point of intramuscular fat were on average approximately +1.0% and −1.0°C, respectively. 2) Intron polymorphisms of sterol regulatory element binding protein-1 (SREBP-1) also affected MUFA. 3) No effect of SCD or SREBP-1 genotypes on any representative carcass traits of Japanese Black cattle was observed in the field population. 4) Additional genetic markers, adipocytes fatty acid binding protein 4 (FABP4) and liver X receptor α, also affected the fatty acid composition. 5) SCD and FABP4 significantly affected fatty acid composition of Holstein steers. These findings bring new insights into the fat-related carcass traits of beef cattle. In addition, the developed DNA makers will contribute to improved meat quality of beef.
