Diacylglycerol acyltransferase (DGAT) activity in relation to muscle fat content and DGAT1 genotype in two different breeds of Bos Taurus (short communication)

Abstract. To circumvent the obvious waste of resources when producing good marbled beef, research is needed to clarify mechanisms which are involved in intramuscular fat storage in cattle. The possible association between the activity of diacylglycerol acyltransferase (DGAT) and muscle fat content was examined in samples of longissimus dorsi (LD) and semitendinosus (ST) muscle from Holstein and Charolais bulls. The Holstein bulls exhibited higher fat content in both muscles and higher marbling score. In Holstein, DGAT activity was enhanced in the LD muscle, and there was a tentative positive relationship between DGAT activity and the fat content in ST muscle. When muscle DGAT activity was examined as a function of DGAT1 genotype for all animals, regardless of breed, the DGAT activity of LD muscle of the K/K genotype was about five-fold greater than for either the K/A or A/A genotypes. Further investigation on the relationship between DGAT1 genotype and i.m. fat is required before this may be developed as a selection tool for marbling.