Impact of genotype, body weight and sex on the prenatal muscle transcriptome of Iberian pigs

Growth is dependent on genotype and diet, even at early developmental stages. In this study, we investigated the effects of genotype, sex, and body weight on the fetal muscle transcriptome of purebred Iberian and crossbred Iberian x Large White pigs sharing the same uterine environment. RNA sequencing was performed on 16 purebred and crossbred fetuses with high body weight (340±14g and 415±14g, respectively) and 16 with low body weight (246±14g and 311±14g, respectively), on gestational day 77. Genotype had the greatest effect on gene expression, with 645 genes identified as differentially expressed (DE) between purebred and crossbred animals. Functional analysis showed differential regulation of pathways involved in energy and lipid metabolism, muscle development, and tissue disorders. In purebred animals, fetal body weight was associated with 35 DE genes involved in development, lipid metabolism and adipogenesis. In crossbred animals, fetal body weight was associated with 60 DE genes involved in muscle development, viability, and immunity. Interestingly, the results suggested an interaction genotype∗weight for some DE genes. Fetal sex had only a modest effect on gene expression. This study allowed the identification of genes, metabolic pathways, biological functions and regulators related to fetal genotype, weight and sex, in animals sharing the same uterine environment. Our findings contribute to a better understanding of the molecular events that influence prenatal muscle development and highlight the complex interactions affecting transcriptional regulation during development.</p

Fungal and ciliate protozoa are the main rumen microbes associated with methane emissions in dairy cattle

14 Pág. Departamento de Mejora Genetica AnimalMitigating the effects of global warming has become the main challenge for humanity in recent decades. Livestock farming contributes to greenhouse gas emissions, with an important output of methane from enteric fermentation processes, mostly in ruminants. Because ruminal microbiota is directly involved in digestive fermentation processes and methane biosynthesis, understanding the ecological relationships between rumen microorganisms and their active metabolic pathways is essential for reducing emissions. This study analysed whole rumen metagenome using long reads and considering its compositional nature in order to disentangle the role of rumen microbes in methane emissions.This research was financed by RTA2015-00022-C03-02 (METALGEN) project from the National Plan of Research, Development and Innovation 2013–2020 and the Department of Economic Development and Competitiveness (Madrid, Spain). A.L.G. was funded by FPI-INIA grant with reference FPI-SGIT2016-06.Peer reviewe

Characterization of bacterial microbiota compositions along the intestinal tract in pigs and their interactions and functions

In addition to its value in meat production, the pig is an interesting animal model for human digestive tract studies due to its physiological similarities. The aim of this study was to describe the microbiome composition, distribution and interaction along the Iberian pig intestinal tract and its role in whole-body energy homeostasis. The V3-V4 region of the 16S rRNA gene was amplified and sequenced from the microbiomes of five gut sections (duodenum, jejunum, ileum, and proximal and distal colon) in thirteen castrated male pigs. A total of 1,669 operational taxonomic units distributed in 179 genera were found among all samples. The two most abundant genera in the small intestine were Lactobacillus and Clostridium, while Prevotella was predominant in the colon. The colon samples were more similar among the pigs and richer in species than the small intestine samples were. In the small intestine, the metagenome prediction pointed to rapid internalization and conversion of the available simple carbohydrates for microbial proliferation and maintenance. In the colon, a competition among anaerobic bacteria for plant polysaccharide degradation to produce short chain fatty acids was found. This study confirms that the energy pathways of the gut microbiome differ along its sections and provides a description of the correlations between genera.info:eu-repo/semantics/publishedVersio

Modulatory Effects of Breed, Feeding Status, and Diet on Adipogenic, Lipogenic, and Lipolytic Gene Expression in Growing Iberian and Duroc Pigs

Meat quality depends on tissue composition which is in turn influenced by different factors, such as diet, genotype, age, or sex. We evaluated the effects of breed, 24 h fasting, and dietary energy source (HO: oleic acid versus CH: carbohydrates) on the expression of candidate genes involved in adipogenesis, lipogenesis, and lipolysis in the adipose tissue from Iberian and Duroc growing pigs. The Iberian pigs showed greater feed intake, backfat thickness, and saturated fatty acids (SFA) content in the subcutaneous fat, whereas the Duroc pigs had greater ham weight and polyunsaturated fatty acids (PUFA) content. In both breeds, the diet induced changes in the fatty acid (FA) composition of subcutaneous fat samples. The HO group had higher monounsaturated fatty acids (MUFA) and oleic acid, and lower SFA than the CH group. Regarding gene expression, breed and feeding status (fasting versus postprandial) had significant effects on gene expression, with quantitative interactions between them, while diet showed negligible effects. In general, adipogenic and lipogenic genes were upregulated in the Iberian pigs and in postprandial samples. In contrast, the expression of lipolytic genes showed complex interaction effects. Our results agree with the phenotypic differences between the Iberian and Duroc breeds and with the inhibition of lipogenesis by fasting. Quantitative interactions between breed and feeding status effects were observed, which indicates a different response to fasting of the two breeds, with the obese Iberian breed showing a more stable expression of lipogenic genes. These results highlight the complexity of lipid metabolism regulation, especially in relation to lipolysis processes

Quantitative trait loci for fatness at growing and reproductive stages in Iberian × Meishan F2 sows

A considerable number of fatness QTL have been identified in growing pigs, but there is a lack of knowledge about the genetic architecture of this trait in gilts and sows. We have performed a genome scan, in 255 Iberian × Meishan F2 sows, for backfat thickness (BF) at 150 (BF150) and 210 (BF210) days of age, 30 days after conception (BF30) and 7–10 days before farrowing (BFbf). We have found one BF150 QTL in SSC6 (120 cM) that was highly significant (P < 0.001) at the chromosome-wide level and suggestive at the genome-wide level (P < 0.1). Ten additional chromosome-wide significant QTL were found for sow BF150 (SSC1, SSC13), BF210 (SSC6, SSC8, SSC15), BF30 (SSC5, SSC6) and BFbf (SSC1, SSC6, SSC13). The location of several of the BF QTL varied depending on the growing and reproductive status of the sow, suggesting that part of these genetic effects may have a temporal pattern of phenotypic expression.Financial support was provided by Ministerio de Educación y Ciencia, Spain (Grant AGL2004-08368-C03/GAN).Peer reviewe

Diversity across Major and Candidate Genes in European Local Pig Breeds

In the frame of the European TREASURE* project, the genetic characterization of 20 local pig breeds is being performed with genetic and genomic tools. The objectives are the study of genetic diversity in these populations and the identification of useful markers for authentication, traceability, conservation and breeding programs. In first place, a candidate gene approach has been applied and the most relevant genes and mutations associated with pig productive, meat quality, reproductive and disease resistance traits have been prioritized and analyzed. Two OpenArray® chips of 32 and 16 SNPs were designed and genotyped in 48 animals from each one of 20 breeds included in the project (Alentejana, Apulo Calabrese, Basque, Bísaro, Black Majorcan, Black Sicilian, Black Slavonian, Casertana, Cinta Senese, Gascon, Iberian, Krskopolje, Lithuanian indigenous wattle, Mangalitsa, Mora Romagnola, Moravka, Old Lithuanian White, Sarda, Schwäbisch Hällisches, Turopolje). Forty SNPs located in 34 genes were successfully genotyped (MC1R, TYRP1, NR6A, PCK1, RYR1, IGF2, MC4R, PHKG1, SCD, GBP5, TAS2R39, TAS2R4, MUC4, ESR1, CYP2E1, LEP, CAST, MTTP, CYB5A, FTO, PPARGC1A, CAPN1, PPARD, CTSL, LEPR, PRKAG3, ACACA, KIT, ACSL4, ADIPOQ, FASN, AHR, FUT1, MSTN). Results provide relevant information regarding genetic diversity and segregation of SNPs responsible for specific production and quality traits. Coat color and morphological trait-genes, showing low level of segregation, and fixed SNPs may be useful for traceability. On the other hand, we detected SNPs which may be useful for breeding programs. For instance, we observed predominance of unfavorable alleles for disease resistance and boar taint genes in most breeds, and segregation of many genes involved in meat quality, fatness and growth. These results joint with ongoing genomic assays, will provide essential information regarding genetic diversity, structure, selective signatures and biological processes responsible for specific production and quality traits

Diversity across Major and Candidate Genes in European Local Pig Breeds

In the frame of the European TREASURE* project, the genetic characterization of 20 local pig breeds is being performed with genetic and genomic tools. The objectives are the study of genetic diversity in these populations and the identification of useful markers for authentication, traceability, conservation and breeding programs. In first place, a candidate gene approach has been applied and the most relevant genes and mutations associated with pig productive, meat quality, reproductive and disease resistance traits have been prioritized and analyzed. Two OpenArray® chips of 32 and 16 SNPs were designed and genotyped in 48 animals from each one of 20 breeds included in the project (Alentejana, Apulo Calabrese, Basque, Bísaro, Black Majorcan, Black Sicilian, Black Slavonian, Casertana, Cinta Senese, Gascon, Iberian, Krskopolje, Lithuanian indigenous wattle, Mangalitsa, Mora Romagnola, Moravka, Old Lithuanian White, Sarda, Schwäbisch Hällisches, Turopolje). Forty SNPs located in 34 genes were successfully genotyped (MC1R, TYRP1, NR6A, PCK1, RYR1, IGF2, MC4R, PHKG1, SCD, GBP5, TAS2R39, TAS2R4, MUC4, ESR1, CYP2E1, LEP, CAST, MTTP, CYB5A, FTO, PPARGC1A, CAPN1, PPARD, CTSL, LEPR, PRKAG3, ACACA, KIT, ACSL4, ADIPOQ, FASN, AHR, FUT1, MSTN). Results provide relevant information regarding genetic diversity and segregation of SNPs responsible for specific production and quality traits. Coat color and morphological trait-genes, showing low level of segregation, and fixed SNPs may be useful for traceability. On the other hand, we detected SNPs which may be useful for breeding programs. For instance, we observed predominance of unfavorable alleles for disease resistance and boar taint genes in most breeds, and segregation of many genes involved in meat quality, fatness and growth. These results joint with ongoing genomic assays, will provide essential information regarding genetic diversity, structure, selective signatures and biological processes responsible for specific production and quality traits

Breed, Diet, and Interaction Effects on Adipose Tissue Transcriptome in Iberian and Duroc Pigs Fed Different Energy Sources

In this study, we analyzed the effects of breed, diet energy source, and their interaction on adipose tissue transcriptome in growing Iberian and Duroc pigs. The study comprised 29 Iberian and 19 Duroc males, which were kept under identical management conditions except the nutritional treatment. Two isoenergetic diets were used with 6% high oleic sunflower oil (HO) or carbohydrates (CH) as energy sources. All animals were slaughtered after 47 days of treatment at an average live weight of 51.2 kg. Twelve animals from each breed (six fed each diet) were employed for ham subcutaneous adipose tissue RNA-Seq analysis. The data analysis was performed using two different bioinformatic pipelines. We detected 837 and 1456 differentially expressed genes (DEGs) according to breed, depending on the pipeline. Due to the strong effect of breed on transcriptome, the effect of the diet was separately evaluated in the two breeds. We identified 207 and 57 DEGs depending on diet in Iberian and Duroc pigs, respectively. A joint analysis of both effects allowed the detection of some breed–diet interactions on transcriptome, which were inferred from RNA-Seq and quantitative PCR data. The functional analysis showed the enrichment of functions related to growth and tissue development, inflammatory response, immune cell trafficking, and carbohydrate and lipid metabolism, and allowed the identification of potential regulators. The results indicate different effects of diet on adipose tissue gene expression between breeds, affecting relevant biological pathways

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

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 piglets of both genetic types, in order to identify genes, pathways and regulatory factors responsible for their phenotypic differences. Contemporary families coming from pure Iberian pigs (IB) or from crossing with Duroc boars (DU×IB) were generated. Piglets (14 from each genetic type) were slaughtered at weaning (28 days) and longissimus dorsi was sampled for composition and gene expression studies. RNA was obtained and hybridized to Affymetrix Porcine Genechip expression arrays.Results Loin muscle chemical composition showed significant differences between genetic types in intramuscular fat content (6.1% vs. 4.3% in IB and DUxIB animals, respectively, P = 0.009) and in saturated (P = 0.019) and monounsaturated fatty acid proportions (P = 0.044). The 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 DU×IB. Transcript differences were validated for a subset of DE genes by qPCR. We observed alteration in biological functions related to extracellular matrix function and organization, cellular adhesion, muscle growth, lipid metabolism and proteolysis. Candidate genes with known effects on muscle growth were found among the DE genes upregulated in DU×IB. Genes related to lipid metabolism and proteolysis were found among those upregulated in IB. Regulatory factors (RF) potentially involved in the expression differences were identified by calculating the regulatory impact factors. Twenty-nine RF were found, some of them with known relationship with tissue development (MSTN, SIX4, IRX3), adipogenesis (CEBPD, PPARGC1B), or extracellular matrix processes (MAX, MXI1). Correlation among the expression of these RF and DE genes show relevant differences between genetic types.Conclusion These results provide valuable information about genetic mechanisms determining the phenotypic differences on 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. Transcription factors and regulatory mechanisms are proposed for these altered biological functions. © 2014 Óvilo et al.; licensee BioMed Central Ltd

Development of a 64 SNV panel for breed authentication in Iberian pigs and their derived meat products

9 Pág.Spanish legislation regulates the labelling of Iberian pig meat and dry-cured products, which are labelled as "Ibérico" or "100% Ibérico" when they come from Duroc x Iberian crossbred or Iberian purebred pigs. Although the analytical authentication of breed origin is not mandatory, a genetic diagnostic tool is demanded by producers and consumers. We have designed a 64 Single Nucleotide Variant genotyping panel displaying extreme allelic frequencies between Duroc and Iberian purebred samples. Average proportions of Iberian alleles of 0.99, 0.01, 0.77 and 0.48 were estimated by admixture clustering analysis of known origin samples, for Iberian and Duroc purebred, 75% Iberian and 50% Iberian classes, respectively. A supervised analysis with 1419 samples showed some overlapping between contiguous classes, but the calculated degrees of separability ranged from 0.800 to 0.996, exceeding the threshold value (0.70) for considering suitable for prediction. Therefore, this panel is a useful genetic tool to infer purebred or crossbred Iberian origin of live animals, meat and dry-cured products.This work was funded by the RZ2012-00006-00-00 grant from the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA). We want to thanks to breeder association AECERIBER and interprofessional association ASICI for providing samples.Peer reviewe