The Effects of Two Selected Single Nucleotide Polymorphisms of the Fatty Acid Synthase Gene on the Fat Content and Fatty Acid Profile of Cow's Milk from the Polish Holstein-Friesian Red-and-White Breed versus Two Polish Red-and-White and Polish Red Conservation Breeds Kept in Poland

Simple Summary The composition of milk fat is of interest to milk producers and consumers. Unsaturated fatty acids are important fats in the human diet, and their profile is influenced by the single-nucleotide polymorphisms (SNPs) of the FASN gene. This study aimed to determine the relationship of two selected SNPs and their genotypic variants with the fat content and fatty acid profile of milk from Polish Red-and-White (ZR), Polish Red (RP), and Polish Holstein-Friesian Red-and-White (RW) breeds. The frequencies of the genotypes of the SNPs were also determined for each breed included in this study. This study enabled the determination of cattle breeds (each with its specific genotype of a given SNP), which proved to be more conducive to the production of health-promoting milk, as evidenced by the fat and fatty acid content of the milk. It was found that, for one SNP, the RP breed (with a specific genotype) exhibited favorable characteristics, while in the case of the other SNP, the RP, ZR, and RW breeds (each with their specific genotypes) demonstrated favorable attributes. This information can be used in cattle-breeding efforts to improve the quality of milk produced.Abstract Fatty acid synthase (FASN) is a metabolic enzyme responsible for the synthesis of fatty acids in milk and meat. The SNPs g.841G/C and g.17924A/G of the FASN gene significantly influence the fat and fatty acid content of milk from cows of various breeds. Therefore, these SNPs were selected for this study. This study aimed to analyze the relationship of SNPs and their genotypes with the fat content and fatty acid profile of milk from Polish Red-and-White (ZR), Polish Red (RP), and Polish Holstein-Friesian Red-and-White (RW) cows. Milk samples were obtained during a milking trial. SNP genotyping was performed using the real-time PCR (HRM) method. It was shown that SNPs (with specific genotypes) were significantly associated with the presence of fatty acids such as C18:1n9t and C18:2n6c in milk. In addition, it was found that the milk fat from the ZR (genotypic variant A/G, AA) and RP (genotypic variant GG, A/G) breeds often exhibited a more attractive fatty acids profile than the milk fat from RW cows. This information can be used by both cattle breeders and people interested in consuming functional foods.