Effect of a diet enriched in PUFA and polyphenols on the expression of genes involved in lipids metabolism in pigs

The content of saturated, monounsaturated and polyunsaturated fatty acids (FA) in pig muscle is very important not only for the consumers’ health but also for the pig processing industry. Breed, diet and genetics are the main factors controlling FA composition of pig meat even if molecular processes and genes controlling lipids metabolism are not yet well known. We performed the present study to improve the knowledge of diet influence on the transcription of genes controlling lipids metabolism. The effects on gene expression of a diet enriched in polyunsaturated fatty acids (PUFA) and polyphenols vs. a control diet were compared. The transcription level of 30 genes involved in FA metabolism and fat deposition in pigs was analysed. Two groups of 12 Italian Large White pigs each, balanced for sex, were reared until the average weight of 149 kg (±10.7 kg). The first group (G1) was fed a standard diet while for the second group (G2) the diet was supplemented with linseed and grape extract. Samples of longissimus dorsi were collected at slaughter and stored at -80 C until RNA extraction. Preliminary data have been obtained for 11 genes (ACACA, ACDC, ADIPOR1, ADIPOR2, CHREBP, ELOVL6 isoform 1 and 2, FADS2, FASN, LXRA, PLIN3, SCD) using qRT-PCR and B2M, HPRT1, POLR2A as normalizing genes. Moreover, the pigs have been genotyped for a SNP in the promoter region of the ELOVL6 gene (ELOVL6:c.-480C>T). The expression levels of this set of genes were compared between the two diets using the Exact Wilcoxon Test in R software. Partial results show that the diet supplementation with PUFA and polyphenols influences the transcription of genes involved in the long chain FA synthesis and in lipids utilization. In particular, both ELOVL6 iso1 and iso2 expressions are higher in G2 than in G1 (p¼.04 and p¼.03, respectively). The same trend is observed for the higher transcription level of ACDC gene in G2 than in G1 group (p¼.06). The ratio between the ELOVL6 isoforms (iso2/iso1) is more elevated in the ELOVL6 CT when compared to TT (p¼.03) and to CC (p¼.06) genotypes. The study is currently underway on the remaining genes. At the end of the analysis of the full set of genes, the correlated gene expressions in both diets and the effects on FA profile of muscle and meat quality traits will also be considered.