The relationship of DGAT1 polymorphisms and milk fatty acids production of cows bred in Iraq (Local, gross and Holstein-Friesen)

Abstract

This study was conducted on a sample of 41 cows (6 local, 21 crosses, and 14 Holstein Friesen) raised in Iraq aged 3-4 years. The study included blood and milk samples. The sequencing technique was used to determine mutations in the DGAT1 gene to determine the effect of genotypes on the quality of fatty acids in cow's milk for all breeds. The GC-MS device was used to measure the levels of milk fatty acids. The study showed the presence of a replacement mutation, as the change was in bases 148 and 149 in the entire coding region of the DGAT1 gene. Where the two bases AA in (Allele 1) changed to GC in (Allele 2) and then to GA in (Allele 3). This mutation led to the change from lysine (K) in allele 1 to alanine and glutamine in Alleles 2 and 3, respectively. The local breed outperformed the percentage of saturated fatty acids over the cross and Holstein-Friesian. While monounsaturated and polyunsaturated, crosses and Holstein-Friesian significantly outperformed the local breed. The first allele significantly exceeded (p<0.01) the other alleles of all breeds in the percentage of saturated fatty acids. In comparison to the first allele, the second allele of cross cows displayed higher levels of monounsaturated and polyunsaturated fatty acids. Regarding unsaturated fatty acids, the third allele of the Friesian breed outperformed the other alleles. Therefore, individual patterns of the DGAT1 gene can be relied upon as markers in the selection process for milk quality purposes.

Keywords

• cattle
• dgat1
• milkfat composition
• milk-free fatty acids