GSE183909
Transcriptome shifts triggered by vitamin A and SCD genotype interaction in Duroc pigs
Background  The composition of intramuscular fat depends on genetic and environmental factors, including the diet. In pigs, we identified a haplotype of three SNP mutations in the steaoryl-coA desaturase (SCD) gene promoter associated with higher content of monounsaturated fatty acids in intramuscular fat. The second of these three SNPs (rs80912566, C>T) affected a putative retinol response element in the SCD promoter. The effect of dietary vitamin A restriction over intramuscular fat content is controversial in pigs as it seems to depend on the genetic line and the duration of the restriction. This study aims to investigate changes in the muscle transcriptome in SCD rs80912566_TT and CC pigs fed with and without vitamin A supplement during the fattening period.  Results  Vitamin A did not affect carcass fattening traits and fatty acid composition in muscle, but we observed an interaction between vitamin A and SCD genotype on the desaturation of muscle fatty acids. The diet without vitamin A supplement tended to enlarge the compositional differences between genotypes. The interaction between diet and genotype was also evident at the transcriptome level, the highest number of differentially expressed genes were detected between SCD rs80912566_TT pigs fed with the two diets.    Conclusions  Restricting dietary vitamin A during the fattening period did not improve intramuscular fat content despite relevant changes in muscle gene expression, both in coding and non-coding genes. Despite this, there was a significant interaction between the SCD genotype and the dietary vitamin A, which affected the quality of the meat through a change in the saturation index of intramuscular fat and activated general pathways of retinol response in a SCD genotype-dependant manner. Overall design: Total of 40 pig muscle samples in 4 comparison groups:  9 samples with SCD-TT genotype and high vitamin A in diet; 8 samples with SCD-TT genotype and low vitamin A in diet; 13 samples with SCD-CC genotype and high vitamin A in diet; and 10 samples with SCD-CC genotype and low vitamin A in diet