Analysis of g.265T>C SNP of fatty acid synthase gene and expression study in skeletal muscle and backfat tissues of Italian Large White and Italian Duroc pigs

Fat deposition is a crucial aspect of pig meat quality as fat content influences both organoleptic and nutritive characteristics of fresh meat, meat products and consumer acceptance. Among genes controlling fat metabolism, the gene encoding fatty acid synthase (FASN) was proposed as a candidate controlling body fat deposition as it is a central enzyme in lipogenesis. The main function of FASN enzyme is the catalysis of the biochemical process that induces the synthesis of palmitate from acetyl-CoA and malonyl-CoA, in the presence of NADPH. This work aims to study variability in the expression level of FASN gene mapped on SSc12 where different QTLs for fat composition and marbling were discovered. In particular, we analysed the SNP T265C for FASN gene identified by Muñoz et al. (2003). The association study conducted on 237 Italian Large White (ILW) sib tested pigs to determine whether this polymorphism affected meat productive traits did not allow finding any associations between the SNP and the reported traits. Regarding the Italian Duroc (ID) breed, no association study was performed because in this breed T allele was very rare. Differential expression between breeds of the target gene in semimembranosus muscle and in backfat tissue was evident comparing FASN transcription level between ID and ILW pigs. In particular, ID pigs have a higher expression level of the gene in skeletal muscle than ILW (P=0.01). In backfat tissue the Italian Large White samples showed higher gene expression level than Italian Duroc pigs with a tendency to significant difference (P=0.08). If further analyses will confirm this results on a large sample, in ID breed the transcriptional level of FASN gene could be considered as marker of fat deposition.