Effects of breed, postnatal development, and nutrition on mRNA expression of the FTO gene in porcine muscle and its relationship with intramuscular fat deposition

The effects of breed, development, and nutrition on mRNA expression of the fat mass and obesityassociated gene (FTO) and its relationship with intramuscular fat (IMF) content in porcine muscle (m. longissimus dorsi; m.l.d.) were estimated. Purebred Jinhua, Zhongbai, Yorkshire, Duroc, Duroc × Zhongbai (DZ), and Duroc × Yorkshire × Landrace (DYL) pigs were used to investigate the effect of breed. Pigs weighing 2.5, 10, 20, 40, 60, and 100 kg were selected to study the effects of different stages of development. To study the effect of nutrition, four diets were selected: corn-soybean (CS), CS with 1.2% conjugated linoleic acid (CLA) or 0.05% creatine monohydrate (CMH), and barley-soybean (BS). All eighty animals were slaughtered, and m.l.d. samples were collected to examine FTO mRNA expression and IMF content. Results showed that breed significantly affected FTO mRNA expression and IMF content. FTO mRNA expression in the studied pigs was in the order: Zhongbai and Yorkshire > Duroc and DZ > Jinhua and DYL. The IMF content ordered by breed was Duroc > DZ > DYL > Jinhua > Zhongbai > Yorkshire. Both FTO mRNA expression and IMF content increased with age of the pigs, with the greatest difference seen between 100 kg pigs and all other weights. In the study, none of the four diets had a significant effect (P > 0.05) on FTO mRNA expression or IMF content. The study demonstrated that FTO mRNA expression increased with increasing body weight and was significantly affected by the breed of pigs. The results showed that FTO mRNA expression had an inconsistent correlation with IMF content between breeds and developmental ages.