Effects of bovine fatty acid synthase, stearoyl-coenzyme A desaturase, sterol regulatory element-binding protein 1, and growth hormone gene polymorphisms on fatty acid composition and carcass traits in Japanese Black cattle

The quality of fat is an important fac- tor in defining the quality of meat. Fat quality is deter- mined by the composition of fatty acids. Among lipid metabolism-related genes, including fatty acid synthe- sis genes, several genetic variations have been reported in the bovine fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD), sterol regulatory element-binding protein 1 (SREBP1), and GH genes. In the present study, we evaluated the single and epistatic effects of 5 genetic variations (4 SNP and 1 insertion/deletion) in 4 genes (FASN, SCD, SREBP1, and GH) on the fatty acid composition of the longissimus thoracis muscle and carcass and meat quality traits in 480 commer- cial Japanese Black cattle. Significant single effects of FASN, SCD, and GH L127V polymorphisms on the fatty acid composition of the longissimus thoracis muscle were detected. The A293V polymorphism of SCD had the largest effect on myristic acid (C14:0, P 0.1) were detected between FASN and SCD for any carcass trait. When the geno- types of 3 markers (FASN, SCD, and GH L127V ) were substituted from the lesser effect allele to the greater ef- fect allele, the proportion of C18:1 increased by 4.46%. More than 20% of the genetic variance in the C18:1 level could be accounted for by these 3 genetic markers. The present results revealed that polymorphisms in 2 fatty acid synthesis genes (FASN and SCD) indepen- dently influenced fatty acid composition in the longis- simus thoracis muscle. These results suggest that SNP in the FASN and SCD genes are useful markers for the improvement of fatty acid composition in commercial Japanese Black cattle.