Project description:Intramuscular fat (IMF) storage is a biological process with strong impact on nutritional and technological properties of meat, and also with relevant consequences on human health. The genetic architecture of IMF content and composition phenotypes has been thoroughly studied in pigs through the identification of quantitative trait loci (QTL) and the estimation of genetic parameters. A question that has not been elucidated yet is if the genetic determinants of IMF-related phenotypes are muscle specific or, conversely, they have broad effects on the whole skeletal muscle compartment. We have addressed this question by generating lipid QTL maps for two muscles with a high commercial value, gluteus medius (GM) and longissimus thoracis et lumborum (LTL), in a Duroc commercial population (N=350). As a complementary approach, we have analysed the mRNA expression pattern of both muscles at a whole genome scale. The lack of concordance between the GM and LTL QTL maps evidenced that the effects of polymorphisms influencing IMF, cholesterol and fatty acids contents are modulated to some extent by complex spatial factors related with muscle location, metabolism and function. This interpretation was supported by our finding that genes influencing cell differentiation, muscle development and function and lipid metabolism are differentially expressed between muscles. These results have important implications on the implementation of genomic selection schemes aimed to improve the lipid profile of swine meat. Moreover, they confirm pigs as a valuable model to dissect the genetic basis of muscle lipid phenotypes of clinical interest in human. Longissimus thoracis et lumborum muscle tissue from 10 high and 9 low fattening Duroc pigs were compared in this study.
Project description:In the last 20 years, there has been significant research towards defining the genetic basis of lipid metabolism and meat quality related traits in pigs. Nowadays, the study of the transcriptome and its regulatory mechanisms allows going far beyond in the genetic dissection of these complex traits. In present study, a genome-wide eQTL scan aiming to detect pig genome regions regulating levels of skeletal muscle mRNA expression has been performed. This study has been conducted on a commercial Duroc population where a number of QTL for muscle fat deposition and fatty acid composition had been detected. GeneChip Porcine Genome® arrays (Affymetrix) were used to determine the gene expression levels of gluteus medius samples from 105 Duroc pigs belonging to two groups with divergent phenotypes for fatness traits. This experimental design aimed to favour detection of eQTL affecting genes related to lipid metabolism and meat quality traits. The whole genome scan with a panel of 110 microsatellites allowed us detecting 613 genome-wide significant eQTL unequally distributed across the pig genome, SSC5 and SSC3 harbouring the highest number of eQTL. Moreover, 11 genome regions with eQTL affecting the expression levels of a high number of genes (eQTL hot spots) have been described. After mapping target probes and discarding low quality probes, a total of 59 cis- and 396 trans-acting eQTL were retained for further analyses. The functional classification showed that lipid-related GO terms were not the most enriched by the list of eQTL-regulated genes. However, a number of regulated genes functionally related to lipid metabolism and fat deposition traits were identified, and their functional relationship with these phenotypes were further investigated. With this purpose, eQTL results were integrated with 1) QTL linkage maps and 2) correlation data between phenotypes and gene expression levels. As a result, a comprehensive list of 29 positional and functional candidate genes was elaborated. These results represent a valuable contribution to the comprehension of genetic regulation of skeletal muscle individual gene expression in swine species, and a first step towards disentangling gene networks and molecular mechanisms involved in lipid metabolism and meat quality traits. 105 gluteus medius samples from 105 animals belonging to two groups of 53 and 52 animals each: HIGH group had higher carcass, plasma and muscle fat content; LOW group had lower carcass, plasma and muscle fat content
Project description:Large White and Meishan pigs were either non-treated or injected with mammalian 1-24 ACTH (Immediate Synachten, Novartis France) at the dose of 250 µg per animal. Pigs were sacrificed either immediately after capture from their home cage (non-treated animals) or 1 hour following ACTH injection. Adrenal glands were immediately collected from pigs and frozen on dry ice and then stored at -80°C until RNA isolation. Keywords: stress response, adrenal, gene expression, pig
Project description:Regulatory Mechanisms of Atrial Remodeling of Mitral Regurgitation Pigs This study enrolled 6 pigs (age: 18 months) and divided into three groups: mitral regurgitation pigs (MR) (n = 2; 2 males sacrificed 12 months after surgery), MR pigs treated with valsartan (MRV) (n = 2; 2 males age-matched to MR sacrificed 12 months after surgery), and normal control pigs (NC) (n = 2; 2 males age-matched to MR pigs). Valsartan (3.43 mg/kg/day), a type I angiotensin II receptor blocker, was administered from one week before surgery and then daily after surgery in the MRV group. We sought to systemically elucidate critical differences in the alteration of RNA expression pattern between the atrial myocardium of pigs with and without MR, and between the atrial myocardium of MR pigs with and without valsartan using high-density oligonucleotide microarrays and functional network enrichment analysis.
Project description:Large White and Meishan pigs were either non-treated or injected with mammalian 1-24 ACTH (Immediate Synachten, Novartis France) at the dose of 250 µg per animal. Pigs were sacrificed either immediately after capture from their home cage (non-treated animals) or 1 hour following ACTH injection. Adrenal glands were immediately collected from pigs and frozen on dry ice and then stored at -80°C until RNA isolation. Keywords: stress response, adrenal, gene expression, pig 47 samples
Project description:Intramuscular fat (IMF) storage is a biological process with strong impact on nutritional and technological properties of meat, and also with relevant consequences on human health. The genetic architecture of IMF content and composition phenotypes has been thoroughly studied in pigs through the identification of quantitative trait loci (QTL) and the estimation of genetic parameters. A question that has not been elucidated yet is if the genetic determinants of IMF-related phenotypes are muscle specific or, conversely, they have broad effects on the whole skeletal muscle compartment. We have addressed this question by generating lipid QTL maps for two muscles with a high commercial value, gluteus medius (GM) and longissimus thoracis et lumborum (LTL), in a Duroc commercial population (N=350). As a complementary approach, we have analysed the mRNA expression pattern of both muscles at a whole genome scale. The lack of concordance between the GM and LTL QTL maps evidenced that the effects of polymorphisms influencing IMF, cholesterol and fatty acids contents are modulated to some extent by complex spatial factors related with muscle location, metabolism and function. This interpretation was supported by our finding that genes influencing cell differentiation, muscle development and function and lipid metabolism are differentially expressed between muscles. These results have important implications on the implementation of genomic selection schemes aimed to improve the lipid profile of swine meat. Moreover, they confirm pigs as a valuable model to dissect the genetic basis of muscle lipid phenotypes of clinical interest in human.