A functional variant in the stearoyl-CoA desaturase (SCD) gene promoter affects gene expression in ovine muscle

The nutritional quality of lambs may be improved with increased stearoyl-CoA desaturase (SCD) gene expression, which increases the desaturation of stearic acid to oleic acid. The aim of this study was to evaluate the effect of the rs412429481 (FJ513370: g.31C > A) SNP located at the SCD gene on the functionality of the gene in lambs reared under different production systems. The effect of the rs412429481 SNP on gene expression in Rasa Aragonesa male lambs slaughtered at 22–24 kg was studied in two experiments. In Experiment 1 (n = 44), the semitendinosus muscle of lambs grazing alfalfa (ALF) or fed concentrates indoors (IND) was analysed; in Experiment 2 (n = 48), the semitendinosus and longissimus thoracis muscles of lambs that received supplementation with dl-a-tocopheryl acetate for different finishing periods were used. In Experiment 1, the effect of the rs412429481 SNP on the expression of the SCD gene in the semitendinosus muscle depended on the feeding group (P < 0.001), as it had no effect in ALF lambs, but CA lambs had greater SCD expression than CC lambs under the IND conditions. Moreover, ALF lambs showed lower levels of SCD gene expression than IND lambs (P < 0.05). In Experiment 2, gene expression was affected by the rs412429481 SNP in both muscles. Animals carrying the C- allele showed a lower expression rate than animals carrying the A- allele. These different expression levels were not associated with changes in the DNA methylation pattern or by the binding of specific nuclear proteins. Finally, we confirmed these results by luciferase assays, demonstrating that the SCD promoter containing the A variant had a 23.9% higher activity than the promoter containing the C variant