Association between mitochondrial DNA copy number and production traits in pigs.

Mitochondria are essential organelles in the regulation of cellular energetic metabolism. Mitochondrial DNA copy number (mtDNA_CN) can be used as a proxy for mitochondria number, size, and activity. The aims of our study are to evaluate the effect of mtDNA_CN and mitochondrial haploblocks on production traits in pigs, and to identify the genetic background of this cellular phenotype.

Candidate markers for enhanced host response to PRRS have scarce adverse effects on pigs' growth and production.

Background: Porcine Reproductive and Respiratory Syndrome (PRRS) is one of the most challenging viral diseases that cause substantial economic losses in the pig industry worldwide. The clinical signs of PRRS depend on, among others, the immunomodulatory properties of the PRRS virus strain, farm health status, herd immunity, and host genetics. The high virulence and mutation rate of PRRS virus limit the efficacy of vaccination programs.

Impact of the leptin receptor gene on pig performance and quality traits.

The recessive T allele of the missense polymorphism rs709596309 C > T of the leptin receptor gene is associated with intramuscular fat. However, its overall impact on pork production is still partial. In this work, we investigated the all-round effects of the TT genotype on lean growth efficiency and carcass, meat and fat quality using data from an experiment that compared the performance of 48 TT and 48 C- (24 CT and 24 CC) Duroc barrows.

A novel QTL region for pH and meat color in Duroc pigs.

One of the most important processes that occur during the transformation of muscle to meat is the pH decline as a consequence of the post-mortem metabolism of muscle tissue. Abnormal pH declines lead to pork defects such as pale, soft, and exudative meat. There is genetic variance for ultimate pH and the role of some genes on this phenotype is well established.

The leptin receptor gene affects piglet behavior and growth.

Piglets with low birth weight present low vitality after farrowing, often leading to impaired weight gain during lactation. A recessive missense variant (C > T) for increased appetite and fatness in the porcine leptin receptor gene (rs709596309) causes a negative maternal effect on the weight of piglets at weaning. However, it is not known whether this variant already exerts an effect on the birth weight and vitality of newborn piglets and on their growing capacity during lactation.

Identification of breed-specific genomic variants in Colombian Creole pig breeds by whole-genome sequencing.

Dissecting genetic variation of local breeds is important for the success of conservation. In this research, we investigated the genomic variation of Colombian Creole (CR) pigs, with a focus on the breed-specific variants in the exonic region of 34 genes with reported effects on adaptive and economic traits. Seven individuals of each of the three CR breeds (CM, Casco de Mula; SP, San Pedreño; and ZU, Zungo) were whole-genome sequenced along with 7 Iberian (IB) pigs and 7 pigs of each of the four most used cosmopolitan (CP) breeds (Duroc, Landrace × Large White, and Pietrain).

Identification of a missense variant in the porcine AGPAT gene family associated with intramuscular fat content through whole-genome sequencing.

The 1-acylglycerol-3-phosphate O-acyltransferases (AGPATs) are enzymes that catalyze the conversion of lysophosphatidic acid to phosphatidic acid, which is a precursor of triacylglycerol, the main fat reservoir in mammals. We used whole-genome sequencing of 205 pigs to identify 6639 genetic variants in the porcine AGPAT gene family. Of these, 166 common variants in the AGPAT5 gene had significant associations with fat content and composition traits.

A genome-wide screen for resilient responses in growing pigs.

Background: There is a growing interest to decipher the genetic background of resilience and its possible improvement through selective breeding. The objective of the present study was to provide new insights into the genetic make-up of resilience in growing pigs by identifying genomic regions and candidate genes associated with resilience indicators. Commercial Duroc pigs were challenged with an attenuated Aujeszky vaccine at 12 weeks of age.

Transcriptome shifts triggered by vitamin A and SCD genotype interaction in Duroc pigs.

Background: The composition of intramuscular fat depends on genetic and environmental factors, including the diet. In pigs, we identified a haplotype of three SNP mutations in the stearoyl-coA desaturase (SCD) gene promoter associated with higher content of monounsaturated fatty acids in intramuscular fat. The second of these three SNPs (rs80912566, C > T) affected a putative retinol response element in the SCD promoter.

A Methodology to Quantify Resilience in Growing Pigs.

There is a growing concern about the genetic determinism of resilience and its possible implementation in breeding programs. The objective of our study was to elaborate novel resilience indicators in growing pigs based on the deviation from the expected growth curve and the increment of the acute-phase protein haptoglobin (HP) after applying a common vaccine. A total of 445 pigs were vaccinated with an attenuated Aujeszky vaccine at 12 weeks of age.

A sequence variant in the diacylglycerol O-acyltransferase 2 gene influences palmitoleic acid content in pig muscle.

The bulk of body fat in mammals is in the form of triacylglycerol. Diacylglycerol O-acyltransferase 2 (DGAT2) catalyses the terminal step in triacylglycerol synthesis. The proximity of DGAT2 with stearoyl-CoA desaturase (SCD) in the endoplasmic reticulum may facilitate provision of de novo SCD-mediated fatty acids as substrate for DGAT2.

Using PRRSV-Resilient Sows Improve Performance in Endemic Infected Farms with Recurrent Outbreaks.

The selection of porcine reproductive and respiratory syndrome (PRRS) resilient sows has been proposed as a strategy to control this disease. A discrete event-based simulation model was developed to mimic the outcome of farms with resilient or susceptible sows suffering recurrent PRRSV outbreaks. Records of both phenotypes were registered in a PRRSV-positive farm of 1500 sows during three years.

Circulating Non-Esterified Fatty Acids as Biomarkers for Fat Content and Composition in Pigs.

Circulating non-esterified fatty acids (NEFA) can reflect the composition of dietary fat or adipose tissues depending on the fasting conditions. Therefore, circulating NEFA may be valuable as biomarkers for meat quality traits, such as intramuscular fat content and fatty acid composition in finishing pigs. Genetic variants that regulate lipid metabolism can also modulate the circulating NEFA.

Antagonistic maternal and direct effects of the leptin receptor gene on body weight in pigs.

Maternal effects on offspring growth can impact survival and evolution of natural and domesticated populations. Genetic correlation estimates often support a negative relationship between direct and maternal effects. However, the genetic underpinnings whereby this antagonism operates are unclear.

Semen quality of Colombian Creole as compared to commercial pig breeds.

Characterization of Creole breeds is still very limited, including reproductive performance. In this research, we assessed the semen quality of three Colombian Creole breeds (Zungo, Casco de Mula and San Pedreño) relative to that of international breeds (Duroc, Belgian Landrace and Pietrain). Two doses from seven boars per breed were evaluated for sperm kinetics and membrane and acrosome integrity using computer-assisted sperm analysis (CASA) and flow cytometry, respectively.

Leptin receptor and fatty acid desaturase-2 gene variants affect fat, color and production profile of dry-cured hams.

The effects of LEPR (rs709596309C > T) and FADS2 (rs321384923A > G) single nucleotide polymorphisms on production and quality attributes in purebred Duroc dry-cured hams were examined. As compared to LEPR-C- hams, the LEPR-TT hams had more intramuscular fat (+2.2% dry matter, P < 0.

Resilience Effects of and DNA Markers during PRRSV Outbreaks in Reproductive Sows.

The porcine reproductive and respiratory syndrome virus (PRRSV) is a major infectious stressor that causes serious health problems and productivity drops. Based on previous genome-wide analyses, we selected and as candidate genes for resilience, and genotyped three mutations, including a 3'UTR variant SGK1_rs338508371 and two synonymous variants TAP1_rs1109026889 and TAP1_rs80928141 in 305 Landrace × Large White sows. All polymorphisms affected the reproductive performance in the outbreak, but not during the endemic phase, thereby indicating a potential use of these markers for resilience.

Modulatory Effect of Protein and Carotene Dietary Levels on Pig gut Microbiota.

In this study we investigated the impact of dietary protein and carotene levels on microbial functions and composition during the last month of purebred fattening Duroc pigs. Fecal microbiota was characterized using 16S ribosomal RNA sequencing at two points of live, 165 (T1) and 195 (T2) days. From 70 to 165 days of age, 32 pigs were divided into two groups fed either a standard-protein (SP) or a low-protein (LP) diet.

Genetic Markers Associated with Field PRRSV-Induced Abortion Rates.

In gilts and sows, the more severe clinical manifestation of porcine reproductive and respiratory syndrome virus (PRRSV) occurs in late gestation and can result in up to a 40% abortion incidence. Despite the known genetic component in resilience to PRRSV, there is scarce information regarding the abortive outcome of this disease. We tested the relationship between eight molecular markers (six from published studies and two identified in the present study in the gene) and the probability of abortion during a PRRSV outbreak, using data from two commercial Landrace x Large White sow farms with an incidence of abortion of 35% and 17%.

Identification of resilient sows in porcine reproductive and respiratory syndrome virus-infected farms1.

The identification of resilient sows can improve reproductive performance in farms exposed to multiple challenges. A common challenge is the porcine reproductive and respiratory syndrome virus (PRRSV). A key issue to deal with disease resilience is to set up a feasible phenotyping strategy.

Identification of resilient sows in Porcine Reproductive and Respiratory Syndrome virus infected farms.

The identification of resilient sows can improve reproductive performance in farms exposed to multiple challenges. A common challenge is the porcine reproductive and respiratory syndrome virus (PRRSV). A key issue to deal with disease resilience is to set up a feasible phenotyping strategy.

Linoleic acid metabolic pathway allows for an efficient increase of intramuscular fat content in pigs.

Background: Intramuscular fat (IMF) content is a relevant trait for high-quality meat products such as dry-cured ham, but increasing IMF has the undesirable correlated effect of decreasing lean growth. Thus, there is a need to find selection criteria for IMF independent from lean growth. In pigs, the proportion of linoleic (C18:2) and arachidonic (C20:4) acids decline with fat deposition and therefore they can be considered as indicators of fatness.

A polymorphism in the fatty acid desaturase-2 gene is associated with the arachidonic acid metabolism in pigs.

Arachidonic acid (C20:4) is related to a wide range of biological effects including lipid homeostasis. The fatty acid desaturase-2 (FADS2) gene encodes for the delta-6-desaturase, which is involved in the biosynthesis of C20:4 from linoleic acid (C18:2). The purpose of this study was to characterise mutations in the promoter of the porcine FADS2, evaluating in particular the effect of one haplotype tagging polymorphism (rs321384923A > G) on the biosynthesis pathway of C20:4.

Genetic Marker Discovery in Complex Traits: A Field Example on Fat Content and Composition in Pigs.

Among the large number of attributes that define pork quality, fat content and composition have attracted the attention of breeders in the recent years due to their interaction with human health and technological and sensorial properties of meat. In livestock species, fat accumulates in different depots following a temporal pattern that is also recognized in humans. Intramuscular fat deposition rate and fatty acid composition change with life.

Genome-Wide Association Study Singles Out SCD and LEPR as the Two Main Loci Influencing Intramuscular Fat Content and Fatty Acid Composition in Duroc Pigs.

Intramuscular fat (IMF) content and fatty acid composition affect the organoleptic quality and nutritional value of pork. A genome-wide association study was performed on 138 Duroc pigs genotyped with a 60k SNP chip to detect biologically relevant genomic variants influencing fat content and composition. Despite the limited sample size, the genome-wide association study was powerful enough to detect the association between fatty acid composition and a known haplotypic variant in SCD (SSC14) and to reveal an association of IMF and fatty acid composition in the LEPR region (SSC6).