Stearoyl CoA desaturase and fatty acid synthase gene polymorphisms and milk fatty acid composition in Chilean Black Friesian cows

Background: in recent years, market attention has increasingly focused on improving the quality of dairy products. Therefore, animal selection for healthier milk fatty acid composition are therefore of interest. Objective: the aim of this study was to identify whether two polymorphisms (c.878T>C in the SCD gene and g.17924A>G in the FASN gene) are related with the fatty acid composition of milk. Methods: individual milk samples were collected from 50 Chilean Black Friesian cows. Fatty acids (FA) from each milk sample were extracted, analyzed, and quantified (mg FA/g of milk) by gas chromatography. The genotype of each sample was also determined using PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Length Polymorphism). Results: milk from cows with a c.878CC genotype in the SCD gene exhibited a greater content of C14:1, C17:1, C18:1n9t, C18:1n9c, and total monounsaturated fatty acids (MUFA), as well as a higher 14:1/14 ratio than other SCD genotypes. In addition, considering the importance of the predominant isomer of conjugated linoleic acid for human diet, we identified a higher content of cis-9, trans-11 conjugated linoleic acid in milk samples from animals that had the c.878CC genotype. For the FASN gene, cows with the g.17924GG genotype presented high contents of C14:0, C16:0, C18:0, C18:1n9t, C18:1n9c, and MUFA. Conclusion: therefore, these polymorphisms could be useful genetic markers for studying the fatty acid composition of dairy milk. Antecedentes: nos últimos anos, o mercado fornecedor de laticínios tem-se voltado ao melhoramento da qualidade dos seus produtos. Por conseguinte, é de interesse a seleção de animais que apresentem uma composição de ácidos graxos mais saudáveis no seu leite. Objetivo: o objetivo principal deste estudo foi identificar dois polimorfismos (c.878T>C no gene SCD e g.17924A>G no gene FASN) e sua associação com a composição de ácidos graxos do leite. Métodos: as amostras de leite foram coletadas de 50 vacas Frison Preto Chileno. Os ácidos graxos (FA) de cada amostra de leite foram extraídos, analisados e quantificados (mg FA/g leite) por cromatografia gasosa. O genótipo de cada amostra foi determinado pela reação de PCR-RFLP (Reação em cadeia de polimerase - polimorfismo de comprimento dos fragmentos de restrição). Resultados: os animais com o genótipo c.878CC no gene SCD têm um teor mais elevado de C14:1, C17:1, C18:1n9t, C18:1n9c e do total de ácidos graxos monoinsaturados (AGM), além de níveis mais elevados d