Investigation of ovine DGAT1 intron 1 variation and its association with variation in carcass traits

Abstract

The economic importance of a carcass is determined by the quantity of saleable meat. The quality of a carcass is determined by the lean meat yield and the ratio of lean meat to fat. Therefore, the heightened quality is portrayed by a carcass that is low in subcutaneous fat, high in lean meat yield with a minimum of 3% of intramuscular fat to give the meat marbling, enhancing eating attributes such as, juiciness and tenderness. Diacylglycerol acyltransferase 1 or DGAT1 has shown to have a strong association with fat production as the last committed step to triglyceride synthesis. In this trial, 338 NZ Romney lambs were genotyped using PCR-SSCP to see if variation occurred in DGAT1 intron 1. It was determined that a variation occurred, and following sequencing, the variation was identified to be a C to T substitution at position 171 between primer sites and equated to three genotypes; AA, AB and BB. 190 lambs were further investigated for association between their genotypes and carcass traits. Three data sets were used, 2015, Glenleith progeny 2014 and Doughboy progeny 2014, of these, two (2015 and Glenleith 2014) showed a strong correlation, P=0.040, P=0.027 respectively, between an increase in leg yield and the presence of allele B. With further analysis it showed that the presence of B increased the leg yield by between 670-706g. It may be assumed that this increase is due to heightened intramuscular fat and therefore the identification of the presence of allele B may be incorporated into a selective breeding system to enhance the intramuscular fat in a leg cut in NZ Romney lambs.