Project description:We studied the influence of genetic type (pure Iberian pigs vs crossbred with Duroc) on l.dorsi transcriptome Background: The two main genetic types in Iberian pig production show important phenotypic differences in growth, fattening and tissue composition since early developmental stages. The objective of this work was the evaluation of muscle transcriptome profile in young animals of both genetic types, in order to identify genes, pathways and transcription factors responsible of their phenotypic differences. Contemporary families coming from pure Iberian pigs (IB) or from crossing with Duroc boars (DUxIB) were generated. Piglets (14 from each genetic type) were sacrificed at weaning (28 days) and longissimus dorsi muscle was sampled for composition and gene expression studies. RNA was obtained and hybridized to Affymetrix Porcine Genechip expression arrays. Results: Loin muscle composition showed significant differences between genetic types in intramuscular fat content (6% vs. 4.2% in IB and DUxIB animals, respectively, P=0.009) and in saturated and monounsaturated fatty acid contents (P=0.019 and P=0.044, respectively). Statistical analysis of gene expression data allowed the identification of 256 differentially expressed (DE) genes between genetic types (FDR<0.10), 102 upregulated in IB and 154 upregulated in DUxIB. The size of the effects ranged between 1.2x and 7.8x. Transcript differences were validated for a subset of DE genes by qPCR. Some candidate genes with known effects on muscle growth were found among the DE genes upregulated in DUxIB (IGF2, collagens, integrins). Genes related to lipid metabolism and proteolysis were found among the genes upregulated in IB (ME1, ELOVL6, caspases, catepsins, ubiquitination proteins). We observed alteration in biological functions related to extracellular matrix organization, cellular adhesion, muscle growth and lipid metabolism. Transcription factors (TF) potentially involved in the expression differences found were identified by calculating the regulatory impact factors (RIF). Sixteen TF were found, some of them with known relationship with muscle development (MSTN, SIX4), adipogenesis (CEBPD, PPARGC1B), or extracellular matrix processes (MAX, MXI1). Correlation among the expression of these TF and DE genes show relevant differences between genetic types. Conclusion: The results contribute valuable information about molecular mechanisms determining the phenotypic differences of growth and meat quality between the genetic types studied, mainly related to the development and function of the extracellular matrix and also to some metabolic processes as proteolysis and lipid metabolism. 28 male piglets were employed. 14 animals coming for pure Iberian parents and 14 coming from the crossing of Duroc boars with Iberian sows. Animals were sacrificed at 28 d of age. At the sacrifice, longissimus dorsi muscle tissue was sampled from each animal.

Project description:We studied the influence of genetic type (pure Iberian pigs vs crossbred with Duroc) on l.dorsi transcriptome Background: The two main genetic types in Iberian pig production show important phenotypic differences in growth, fattening and tissue composition since early developmental stages. The objective of this work was the evaluation of muscle transcriptome profile in young animals of both genetic types, in order to identify genes, pathways and transcription factors responsible of their phenotypic differences. Contemporary families coming from pure Iberian pigs (IB) or from crossing with Duroc boars (DUxIB) were generated. Piglets (14 from each genetic type) were sacrificed at weaning (28 days) and longissimus dorsi muscle was sampled for composition and gene expression studies. RNA was obtained and hybridized to Affymetrix Porcine Genechip expression arrays. Results: Loin muscle composition showed significant differences between genetic types in intramuscular fat content (6% vs. 4.2% in IB and DUxIB animals, respectively, P=0.009) and in saturated and monounsaturated fatty acid contents (P=0.019 and P=0.044, respectively). Statistical analysis of gene expression data allowed the identification of 256 differentially expressed (DE) genes between genetic types (FDR<0.10), 102 upregulated in IB and 154 upregulated in DUxIB. The size of the effects ranged between 1.2x and 7.8x. Transcript differences were validated for a subset of DE genes by qPCR. Some candidate genes with known effects on muscle growth were found among the DE genes upregulated in DUxIB (IGF2, collagens, integrins). Genes related to lipid metabolism and proteolysis were found among the genes upregulated in IB (ME1, ELOVL6, caspases, catepsins, ubiquitination proteins). We observed alteration in biological functions related to extracellular matrix organization, cellular adhesion, muscle growth and lipid metabolism. Transcription factors (TF) potentially involved in the expression differences found were identified by calculating the regulatory impact factors (RIF). Sixteen TF were found, some of them with known relationship with muscle development (MSTN, SIX4), adipogenesis (CEBPD, PPARGC1B), or extracellular matrix processes (MAX, MXI1). Correlation among the expression of these TF and DE genes show relevant differences between genetic types. Conclusion: The results contribute valuable information about molecular mechanisms determining the phenotypic differences of growth and meat quality between the genetic types studied, mainly related to the development and function of the extracellular matrix and also to some metabolic processes as proteolysis and lipid metabolism.

Project description: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, transcriptional regulation and genetic polymorphisms that could be associated with the observed phenotypic differences between IB and IBxDU pigs. Nine IB and 10 IBxDU pigs were slaughtered at birth. Morphometric measures and blood samples were obtained and samples from Biceps femoris muscle were employed for compositional and transcriptome analysis by RNA-Seq technology. Phenotypic differences were evident at this early age, including greater body size and weight in IBxDU and greater Biceps femoris intramuscular fat and plasma cholesterol content in IB newborns. We detected 150 differentially expressed genes between IB and IBxDU neonates (p < 0.01 and Fold-Change > 1. 5). Several were related to adipose and muscle tissues development (DLK1, FGF21 or UBC). The functional interpretation of the transcriptomic differences revealed enrichment of functions and pathways related to lipid metabolism in IB and to cellular and muscle growth in IBxDU. Protein catabolism, cholesterol biosynthesis and immune system were functions enriched in both genotypes. We identified transcription factors potentially affecting the observed gene expression differences. Some of them have known functions on adipogenesis (CEBPA, EGRs), lipid metabolism (PPARGC1B) and myogenesis (FOXOs, MEF2D, MYOD1), which suggest a key role in the meat quality differences existing between IB and IBxDU hams. We also identified several polymorphisms showing differential segregation between IB and IBxDU pigs. Among them, non-synonymous variants were detected in several transcription factors as PPARGC1B gene, which could be associated to altered gene function. Taken together, these results provide information about candidate genes, metabolic pathways and genetic polymorphisms potentially involved in phenotypic differences between IB and IBxDU associated to meat quality and production traits.

Dataset Information

Longissimus dorsi transcriptome analysis of purebred and crossbred Iberian pigs differing in muscle characteristics.

Publications

Longissimus dorsi transcriptome analysis of purebred and crossbred Iberian pigs differing in muscle characteristics.

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