Effects of Stearoyl-Coenzyme A Desaturease 1 Gene Expression on Blood Fatty Acid Composition of Pastured Angus Cattle

The purpose of this study was to investigate the effect of stearoyl-coenzyme desaturase 1 (SCD1) gene expression on blood fatty acid composition of Angus cattle raised on pasture. Blood samples of 38 pastured Angus cattle with average body mass of (698 ± 34) kg and at the age of 48 months were collected for fatty acid composition and content determination. The expression of the SCD1 gene was detected by real-time fluorescence quantitative polymerase chain reaction, and the influence of SCD1 gene mutation at C878T on fatty acid composition of blood samples of cattle was detected by first-generation sequencing technology. The correlation between SCD1 gene expression and fatty acid composition was further analyzed. The results showed the presence of 36 main fatty acids in blood samples, with the major saturated fatty acids (SFA) being palmitic acid (C_16:0, 22.53%) and stearic acid (C_18:0, 26.95%). Oleic acid (C_{18:1 n-9c}) was identified as the most abundant monounsaturated fatty acid (MUFA) (15.09%). The significance analysis indicated that SCD1 gene expression had significant effects on myristic acid (C_14:0), myristic acid (C_14:1), C_16:0, C_16:1, C_18:0, C_{18:1 n-9c}, linoleic acid (C_{18:2 n-6c}), MUFA and MUFA/SFA ratio as well as C₁₄ index, C₁₈ index, total unsaturation index and elongation index of fatty acids. Additionally, the correlation analysis results suggested that SCD1 gene expression was positively correlated with C_16:0, palmitoleic acid (C_16:1), C_18:0, C_{18:1 n-9c} and MUFA. SCD1 gene exhibited C/T mutation at the 878 site, yielding three genotypes: CC, TT and CT. No significant difference between different genotypes and fatty acid composition was found. Overall, the expression of SCD1 gene in the blood of pastured Angus cattle can regulate its fatty acid composition and thus can be used as a reference gene for genetic markers.