Longissimus dorsi muscle transcriptome in pure and crossbred Iberian pigs at birth and growing stages

Iberian ham production includes both purebred (IB) and Duroc-crossbred (IBxDU) Iberian pigs, which show important differences in meat quality and production traits, such as muscle growth and fatness. This experiment was conducted to investigate gene expression differences that could be associated with the observed phenotypic differences between IB and IBxDU pigs. Nine IB and 10 IBxDU pigs were slaughtered at birth, and seven IB and 10 IBxDU at four months of age (growing period). Muscle transcriptome was analyzed on LD samples with RNA-Seq technology. We detected 261 differentially expressed genes between IB and IBxDU neonates and 113 at growth (p < 0.01 and Fold-Change > 1. 5). Newborns transcriptome reflected a highly proliferative developmental stage, while older pigs showed upregulation of catabolic and muscle functioning processes. Regarding the genetic type effect, IBxDU newborns showed enrichment of gene pathways involved in muscle growth, in agreement with the higher prenatal growth observed in these pigs. However, IB growing pigs showed enrichment of pathways involved in protein deposition and cellular growth, supporting the catch-up growth experienced by IB pigs during this period. Moreover, newborn and growing IB pigs showed more active glucose and lipid metabolism than IBxDU pigs. Overall design: In total 24 longissimus dorsi samples were analyzed, 6 coming from purebred Iberian male newborns and 6 coming from crossbred male newborns (IberianxDuroc), at each stage (birth and four months of age)

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Ayuso M, Fernández A, Núñez Y, Benítez R, Isabel B, Fernández AI, Rey AI, González-Bulnes A, Medrano JF, Cánovas Á, López-Bote CJ, Óvilo C