Pearson's correlation between fatty acid profile and gene expression of transcription factors and lipogenic enzymes in the muscle of young bulls fed soybean or cottonseed, with or without vitamin E

Abstract Text: This study had the objective to evaluate the correlations between mRNA expression of peroxisome proliferator-activated receptor-α (PPAR-α), sterol regulatory element binding protein-1c (SREBP-1c); stearoyl-CoA desaturase-1 (SCD1), acetyl CoA carboxylase (ACC) and fatty acid profile in the muscle of young bulls fed diets containing soybean grain or cottonseed, with or without vitamin E supplementation. Twenty-eight Red North young bulls with an average age of 20 months and initial average live weight of 339 +15 kg were allotted in a completely randomized design using a 2 x 2 factorial arrangement. The animals were slaughtered at an average weight of 456 ± 15.1 kg (P>0.05) and two samples were then taken from the longissimus dorsi (LD) muscle of each animal between the 12th and 13th ribs. The first sample was stored at -20 ºC for subsequent lipid extraction and fatty acid analysis using gas chromatography; and the second sample was stored at -80°C for quantitative gene expression analysis by RT-qPCR. After analyzes of fatty acid content and relative gene expression according to the diets, data of all treatments were used to carry out the Pearson’s correlation study using the PROC CORR tool of SAS 9.3. Linoleic acid content was negatively (-0.38; P<0.05) and positively (0.38; P<0.05) correlated with expression of PPAR-α and SREBP-1c, respectively. On the other hand, α-linolenic and oleic acids were positively (0.55; P<0.01 and 0.46; P<0.05, respectively) correlated with PPAR-α, showing an agonistic effect of these fatty acids on the nuclear receptor. In addition, correlations between linoleic acid content and expression of SCD1 (0.39; P<0.05) and ACC (-0.38; P<0.05) were observed in the LD muscle. No correlations (P>0.05) between arachidonic acid and the expression of PPAR-α and SREBP-1c were observed. Oleic and palmitoleic acids had positive correlations with ACC mRNA (0.47; P<0.05 and 0.41; P<0.05, respectively), but a negative correlation between stearic acid content and ACC gene expression was observed (-0.38; P<0.05). In conclusion, linoleic acid was the main fatty acid that influenced expressions of PPAR-α, SREBP-1c, SCD1 and ACC. Furthermore, unsaturated fatty acids affect in different ways gene expression of these genes. Funded by Fapemig, CNPq, Capes, and INCT-CA.

Keywords: PPAR, SCD, SREBP-1c