Identification of genetic polymorphisms in the stearoyl CoA desaturase gene and its association with milk quality traits in Najdi sheep

The nutritional quality of milk, which is determined by its fatty acid (FA) composition, and the candidate gene stearoyl-CoA desaturase (SCD) can be used in conjunction with these traits to improve the quality of dairy products. The aim of this study was to identify single nucleotide polymorphism (SNP) of the SCD gene and its associations with the milk composition and FA profiles of Najdi dairy sheep and 72 multiparous Najdi ewes under the same feeding system. Milk and blood samples were taken during the first lactation (<30 days in milk). Analysis and alignment DNA sequences identified SNP g.87C>A in the promoter and SNP g.1033G>A in exon 2 of the SCD gene. Association analysis showed that SNP g.87C>A was significantly associated (P = 0.05) with palmitic acid (C16:0), alpha linoleic acid (ALA - C18:3-n3), linolenic acid (LA - C18:2-n6), and polyunsaturated fatty acid (PUFA). In addition, the SNP g.1033G>A showed a significant (P < 0.05) association with odd-chain FAs (heptadecanoic acid [C17:0] and heneicosanoic acid [C21:0]). The results showed that SCD gene may be important in the synthesis of PUFA and contributes to healthier dairy products. Overall, the Najdi breed SNP SCD gene showed that the association with milk traits is crucial, particularly with essential fatty acids: ALA-n3 and LA-n6 in milk fat.