The effect of sex and DGAT1 gene polymorphism on fat deposition traits in simmental beef cattle

This study investigated diacylglycerol O-acyltransferase 1 (DGAT1) gene K232A mutation in Simmental cattle and its effects on fat deposition traits. The sample (n=26) consisted of yearling bulls and beef heifers from an intensive rearing system in Croatia. Carcass fatness was assessed by total dissection method, whereas intramuscular fat (m. longissimus dorsi) content was determined using Soxhlet extraction with hydrolysis. Intramuscular fatty acid composition was determined by gas liquid chromatography using in situ transesterification. The muscle DNA was extracted and Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCRRFLP) analysis of the 411 bp fragment of DGAT1 gene was applied. The DGAT1 K allele was less frequent in heifers than in bulls, with the overall allelic frequency of 17% K allele. Only KA and AA genotypes were obtained, without deviation from the Hardy-Weinberg equilibrium. Heifers showed a higher degree of carcass and muscle fattening with more unsaturated intramuscular fat than bulls; however, there was no interaction between sex and DGAT1 gene. Generally, no significant difference between DGAT1 AA and KA animals was observed for any of the examined traits, except the slightly higher carcass share of the fattest beef category and higher intramuscular C14:0 desaturation index in KA heterozygous