The downregulation of genes encoding muscle proteins have a potential role in the development of scrotal hernia in pigs.

BACKGROUND: Testicular descent is a physiological process regulated by many factors. Eventually, disturbances in the embryological/fetal development path facilitate the occurrence of scrotal hernia, a congenital malformation characterized by the presence of intestinal portions within the scrotal sac due to the abnormal expansion of the inguinal ring. In pigs, some genes have been related to this anomaly, but the genetic mechanisms involved remain unclear. This study aimed to investigate the expression profile of a set of genes potentially involved with the manifestation of scrotal hernia in the inguinal ring tissue. METHODS AND RESULTS: Tissue samples from the inguinal ring/canal of normal and scrotal hernia-affected male pigs with approximately 30 days of age were used. Relative expression analysis was performed using qPCR to confirm the expression profile of 17 candidate genes previously identified in an RNA-Seq study. Among them, the Myosin heavy chain 1 (MYH1), Desmin (DES), and Troponin 1 (TNNI1) genes were differentially expressed between groups and had reduced levels of expression in the affected animals. These genes encode proteins involved in the formation of muscle tissue, which seems to be important for increasing the resistance of the inguinal ring to the abdominal pressure, which is essential to avoid the occurrence of scrotal hernia. CONCLUSIONS: The downregulation of muscular candidate genes in the inguinal tissue clarifies the genetic mechanisms involved with this anomaly in its primary site, providing useful information for developing strategies to control this malformation in pigs and other mammals.

Genomic regions, candidate genes, and pleiotropic variants associated with physiological and anatomical indicators of heat stress response in lactating sows.

BACKGROUND: Heat stress (HS) poses significant threats to the sustainability of livestock production. Genetically improving heat tolerance could enhance animal welfare and minimize production losses during HS events. Measuring phenotypic indicators of HS response and understanding their genetic background are crucial steps to optimize breeding schemes for improved climatic resilience. The identification of genomic regions and candidate genes influencing the traits of interest, including variants with pleiotropic effects, enables the refinement of genotyping panels used to perform genomic prediction of breeding values and contributes to unraveling the biological mechanisms influencing heat stress response. Therefore, the main objectives of this study were to identify genomic regions, candidate genes, and potential pleiotropic variants significantly associated with indicators of HS response in lactating sows using imputed whole-genome sequence (WGS) data. Phenotypic records for 18 traits and genomic information from 1,645 lactating sows were available for the study. The genotypes from the PorcineSNP50K panel containing 50,703 single nucleotide polymorphisms (SNPs) were imputed to WGS and after quality control, 1,622 animals and 7,065,922 SNPs were included in the analyses. RESULTS: A total of 1,388 unique SNPs located on sixteen chromosomes were found to be associated with 11 traits. Twenty gene ontology terms and 11 biological pathways were shown to be associated with variability in ear skin temperature, shoulder skin temperature, rump skin temperature, tail skin temperature, respiration rate, panting score, vaginal temperature automatically measured every 10 min, vaginal temperature measured at 0800 h, hair density score, body condition score, and ear area. Seven, five, six, two, seven, 15, and 14 genes with potential pleiotropic effects were identified for indicators of skin temperature, vaginal temperature, animal temperature, respiration rate, thermoregulatory traits, anatomical traits, and all traits, respectively. CONCLUSIONS: Physiological and anatomical indicators of HS response in lactating sows are heritable but highly polygenic. The candidate genes found are associated with important gene ontology terms and biological pathways related to heat shock protein activities, immune response, and cellular oxidative stress. Many of the candidate genes with pleiotropic effects are involved in catalytic activities to reduce cell damage from oxidative stress and cellular mechanisms related to immune response.

Comparison of ICSI, IVF, and in vivo derived embryos to produce CRISPR-Cas9 gene-edited pigs for xenotransplantation.

Genome editing in pigs for xenotransplantation has seen significant advances in recent years. This study compared three methodologies to generate gene-edited embryos, including co-injection of sperm together with the CRISPR-Cas9 system into oocytes, named ICSI-MGE (mediated gene editing); microinjection of CRISPR-Cas9 components into oocytes followed by in vitro fertilization (IVF), and microinjection of in vivo fertilized zygotes with the CRISPR-Cas9 system. Our goal was to knock-out (KO) porcine genes involved in the biosynthesis of xenoantigens responsible for the hyperacute rejection of interspecific xenografts, namely GGTA1, CMAH, and ß4GalNT2. Additionally, we attempted to KO the growth hormone receptor (GHR) gene with the aim of limiting the growth of porcine organs to a size that is physiologically suitable for human transplantation. Embryo development, pregnancy, and gene editing rates were evaluated. We found an efficient mutation of the GGTA1 gene following ICSI-MGE, comparable to the results obtained through the microinjection of oocytes followed by IVF. ICSI-MGE also showed higher rates of biallelic mutations compared to the other techniques. Five healthy piglets were born from in vivo-derived embryos, all of them exhibiting biallelic mutations in the GGTA1 gene, with three displaying mutations in the GHR gene. No mutations were observed in the CMAH and ß4GalNT2 genes. In conclusion, in vitro methodologies showed high rates of gene-edited embryos. Specifically, ICSI-MGE proved to be an efficient technique for obtaining homozygous biallelic mutated embryos. Lastly, only live births were obtained from in vivo-derived embryos showing efficient multiple gene editing for GGTA1 and GHR.

Identification of eQTLs using different sets of single nucleotide polymorphisms associated with carcass and body composition traits in pigs.

BACKGROUND: Mapping expression quantitative trait loci (eQTLs) in skeletal muscle tissue in pigs is crucial for understanding the relationship between genetic variation and phenotypic expression of carcass traits in meat animals. Therefore, the primary objective of this study was to evaluate the impact of different sets of single nucleotide polymorphisms (SNP), including scenarios removing SNPs pruned for linkage disequilibrium (LD) and SNPs derived from SNP chip arrays and RNA-seq data from liver, brain, and skeletal muscle tissues, on the identification of eQTLs in the Longissimus lumborum tissue, associated with carcass and body composition traits in Large White pigs. The SNPs identified from muscle mRNA were combined with SNPs identified in the brain and liver tissue transcriptomes, as well as SNPs from the GGP Porcine 50 K SNP chip array. Cis- and trans-eQTLs were identified based on the skeletal muscle gene expression level, followed by functional genomic analyses and statistical associations with carcass and body composition traits in Large White pigs. RESULTS: The number of cis- and trans-eQTLs identified across different sets of SNPs (scenarios) ranged from 261 to 2,539 and from 29 to 13,721, respectively. Furthermore, 6,180 genes were modulated by eQTLs in at least one of the scenarios evaluated. The eQTLs identified were not significantly associated with carcass and body composition traits but were significantly enriched for many traits in the "Meat and Carcass" type QTL. The scenarios with the highest number of cis- (n = 304) and trans- (n = 5,993) modulated genes were the unpruned and LD-pruned SNP set scenarios identified from the muscle transcriptome. These genes include 84 transcription factor coding genes. CONCLUSIONS: After LD pruning, the set of SNPs identified based on the transcriptome of the skeletal muscle tissue of pigs resulted in the highest number of genes modulated by eQTLs. Most eQTLs are of the trans type and are associated with genes influencing complex traits in pigs, such as transcription factors and enhancers. Furthermore, the incorporation of SNPs from other genomic regions to the set of SNPs identified in the porcine skeletal muscle transcriptome contributed to the identification of eQTLs that had not been identified based on the porcine skeletal muscle transcriptome alone.

Investigating the impact of non-additive genetic effects in the estimation of variance components and genomic predictions for heat tolerance and performance traits in crossbred and purebred pig populations.

BACKGROUND: Non-additive genetic effects are often ignored in livestock genetic evaluations. However, fitting them in the models could improve the accuracy of genomic breeding values. Furthermore, non-additive genetic effects contribute to heterosis, which could be optimized through mating designs. Traits related to fitness and adaptation, such as heat tolerance, tend to be more influenced by non-additive genetic effects. In this context, the primary objectives of this study were to estimate variance components and assess the predictive performance of genomic prediction of breeding values based on alternative models and two independent datasets, including performance records from a purebred pig population and heat tolerance indicators recorded in crossbred lactating sows. RESULTS: Including non-additive genetic effects when modelling performance traits in purebred pigs had no effect on the residual variance estimates for most of the traits, but lower additive genetic variances were observed, especially when additive-by-additive epistasis was included in the models. Furthermore, including non-additive genetic effects did not improve the prediction accuracy of genomic breeding values, but there was animal re-ranking across the models. For the heat tolerance indicators recorded in a crossbred population, most traits had small non-additive genetic variance with large standard error estimates. Nevertheless, panting score and hair density presented substantial additive-by-additive epistatic variance. Panting score had an epistatic variance estimate of 0.1379, which accounted for 82.22% of the total genetic variance. For hair density, the epistatic variance estimates ranged from 0.1745 to 0.1845, which represent 64.95-69.59% of the total genetic variance. CONCLUSIONS: Including non-additive genetic effects in the models did not improve the accuracy of genomic breeding values for performance traits in purebred pigs, but there was substantial re-ranking of selection candidates depending on the model fitted. Except for panting score and hair density, low non-additive genetic variance estimates were observed for heat tolerance indicators in crossbred pigs.

Genetic characterization of domestic pigs in the core zone of swine production of Argentina.

Argentina is a small player in the global pork market, contributing only 0.7% of the total production. With increasing global demand for meat, there is an opportunity for countries with an agricultural profile to grow their pork production. However, there is a need to understand the current state of the pork production sector in all aspects to inform decision-making. The aim of this study was to genetically characterize pig herds from different production strata in the primary region for pork production in the country. For this purpose, phylogenetic and genetic variability analyses were performed using the mitochondrial control region marker (n=95 pig samples). Moreover, genotyping of ryr1 and PRKAG3 genes (n=108 pig samples) were performed to evaluate the frequency of deleterious alleles for meat quality traits in the region. The results showed high levels of genetic variability in the pig herds (Hd= 0.840 ± 0.031 and π= 0.010 ± 0.001), with a creole sow and Iberian lineage standing out in the phylogeny. The genotyping of the ryr1 marker revealed the presence of the deleterious t allele in all analyzed strata. However, the RN-allele of the PRKAG3 gene was detected only in the two lower strata. This study represents the first analysis of the phylogenetic relationships among domestic pigs from Argentina and provides an initial assessment of genetic variability in the region. Additionally, the results present, for the first time, the frequency of deleterious alleles for pig production in the productive core area, demonstrating their prevalence.

Genetic diversity in creole pigs in south central Peru.

The creole pigs represent 67% of the national population in Peru. They are a source of economic income in rural communities, and due to their rusticity, they are not much labor demanding. However, knowledge about its genetic diversity remains scarce. The objective of this study was to determine the population structure and genetic diversity of creole pigs from rural communities in south central Peru. Thirteen microsatellites were used to characterize 120 creole pigs from the departments of Ayacucho (57) and Apurimac (63). The samples were taken from hair follicles and ear tissue. Nine microsatellites were highly polymorphic and informative (PIC > 0.5) for both departments. The Ayacucho population had a mean number of alleles (MNA) and expected heterozygosity (HE) of 8.8 and 0.68, respectively, while in the Apurimac population, these were 8.9 and 0.71, respectively. Both populations showed in less than 50% of their loci a deviation from Hardy-Weinberg equilibrium. There was a moderate genetic structure according to the analysis of molecular variance and the FST statistics (0.06), which was corroborated by Bayesian methods. In conclusion, the genetic diversity was mostly due to the intrapopulation variance (91%). Some individuals from Ayacucho shared similar alleles with those from Apurimac. This latter result may be due to their geographic proximity and the introduction of the same new exotic breeds. This is the first research on the genetic diversity of creole pigs in south central Peru. In fact, this study could serve as a basis for conservation strategies and actions in this region.

Evaluation of different percentages of Duroc genes and gender on growth, carcass and meat quality traits for pigs.

The effect of different percentages of Duroc genes in crossbreeding (5, 50 and 100%), the gender (immunocastrated males - ICM and females) and their interaction was evaluated on growth, carcass and meat quality traits for pigs. Crossbreds (50% Duroc) had greater average daily feed intake, hot carcass weight and backfat thickness but lower meat yield when compared to 5% Duroc crossbreds and purebred (100% Duroc) animals (P < 0.05). Purebred (100% Duroc) animals had the lowest backfat thickness and subcutaneous fat thickness, and the greatest muscle depth and meat yield (P < 0.05). ICM animals had better feed conversion, greater average daily gain, hot carcass weight and amount of meat, and lower hot carcass yield, cold carcass weight, Longissimus thoracis depth, rib with belly and ham weights compared to females (P < 0.05). Marbling scores were greater in purebred (100%) animals (P < 0.05). The meat from 50% Duroc crossbreds and 100% Duroc purebred pigs was more reddish pink in color than 5% Duroc crossbreds (P < 0.05). Also, marbling scores were greater for females compared to ICM (P < 0.05). Purebred (100% Duroc) animals required more medications during production (P < 0.05).

Heritability estimates and predictive ability for pig meat quality traits using identity-by-state and identity-by-descent relationships in an F2 population.

Genomic relationships can be computed with dense genome-wide genotypes through different methods, either based on identity-by-state (IBS) or identity-by-descent (IBD). The latter has been shown to increase the accuracy of both estimated relationships and predicted breeding values. However, it is not clear whether an IBD approach would achieve greater heritability ( h 2 ) and predictive ability ( r ̂ y , y ̂ ) than its IBS counterpart for data with low-depth pedigrees. Here, we compare both approaches in terms of the estimated of h 2 and r ̂ y , y ̂ , using data on meat quality and carcass traits recorded in experimental crossbred pigs, with a pedigree constrained to only three generations. Three animal models were fitted which differed on the relationship matrix: an IBS model ( G IBS ), an IBD (defined within the known pedigree) model ( G IBD ), and a pedigree model ( A 22 ). In 9 of 20 traits, the range of increase for the estimates of σ u 2 and h 2 was 1.2-2.9 times greater with G IBS and G IBD models than with A 22 . Whereas for all traits, both parameters were similar between genomic models. The r ̂ y , y ̂ of the genomic models was higher compared to A 22 . A scarce increment in r ̂ y , y ̂ was found with G IBS when compared to G IBD , most likely due to the former recovering sizeable relationships among founder F0 animals.

Molecular characteristics and transcriptional regulatory of spermatogenesis-related gene RFX2 in adult Banna mini-pig inbred line (BMI)

RFX2 plays critical roles in mammalian spermatogenesis and cilium maturation. Here, the testes of 12-month-old adult boars of Banna mini-pig inbred line (BMI) were subjected to whole-transcriptome sequencing. The results indicated that the average expression (raw count) of RFX2 gene in BMI testes was 16138.25, and the average expression value of the corresponding transcript ENSSSCT00000043271.2 was 123.1898. The CDS of RFX2 obtained from BMI testes was 2,817 bp (GenBank accession number: OL362242). Gene structure analysis showed that RFX2 was located on chromosome 2 of the pig genome with 19 exons. Protein structure analysis indicated that RFX2 contains 728 amino acids with two conserved domains. Phylogenetic analysis revealed that RFX2 was highly conserved with evolutionary homologies among mammalian species. Other analyses, including PPI networks, KEGG, and GO, indicated that BMI RFX2 had interactions with 43 proteins involving various functions, such as in cell cycle, spermatid development, spermatid differentiation, cilium assembly, and cilium organization, etc. Correlation analysis between these proteins and the transcriptome data implied that RFX2 was significantly associated with FOXJ1, DNAH9, TMEM138, E2F7, and ATR, and particularly showed the highest correlation with ATR, demonstrating the importance of RFX2 and ART in spermatogenesis. Functional annotation implied that RFX2 was involved in 17 GO terms, including three cellular components (CC), six molecular functions (MF), and eight biological processes (BP). The analysis of miRNA-gene targeting indicated that BMI RFX2 was mainly regulated by two miRNAs, among which four lncRNAs and five lncRNAs competitively bound ssc-miR-365-5p and ssc-miR-744 with RFX2, respectively. Further, the dual-luciferase report assay indicated that the ssc-miR-365-5p and ssc-miR-744 significantly reduced luciferase activity of RFX2 3'UTR in the 293T cells, suggesting that these two miRNAs regulated the expression of RFX2. Our results revealed the important role of RFX2 in BMI spermatogenesis, making it an intriguing candidate for follow-up studies.(AU)

Expression analysis of m6A-related genes in various tissues of Meishan pigs at different developmental stages

To characterize the N6-methyladenosine (m6A)-related gene expression profiles in various tissues of Meishan pigs at different stages, m6A modification-related genes (METTL3, METTL14, METTL16, WTAP, RBM15, and FTO) were detected from newborn to physical maturity of Meishan pigs at eight important developmental stages (1, 7, 14, 21, 28, 35, 134, and 158 days old). The expression of m6A-related genes was tissue-specific. Furthermore, the level of METTL3 messenger RNA (mRNA) was higher on day 35 than in other stages in most tissues, and the expression of METTL14 increased after day 35, and FTO exhibited a peak on day 14 in muscle, intestine, lymph nodes, thymus, and kidney. This study provided a reference for an in-depth study of the expression patterns of m6A modification-related genes in Meishan pigs.

Genetic relationships of the Yucatan black hairless pig with Iberian breeds using single nucleotide polymorfisms / Relações genéticas de porcos pretos calvos de Yucatán com raças ibéricas usando Polimorfismo de nucleotídeos isolados

To conduct ex-situ creole pig conservation programs, it is essential to determine which breeding animals will be used, preferentially those with a more significant Iberian genetic component to preserve their origin. This study used a Yucatan black hairless pigs (YBHP) subpopulation to estimate its genetic diversity and population structure. One hundred four adult pigs were selected for the absence of hair, black skin (without spots), black hoof, and straight snout. The porcine-GGP-50K chip was used for SNP genotyping in YBHP, and information on Iberian and Yucatán hairless pigs from the United States (USYU) was taken from databases. All analysis was performed using PLINK v1.9 and v2.1 software. Inbreeding and fixation index values were lower in YBHP, with high observed heterozygosity and allogamy index values, which agree with those obtained in the populations of Canarias and Chato Murciano. According to the clusters generated by the "Genome-Wide Identity by State" analysis, four groups were identified, one of which included pigs from Guadyerbas, USYU, and YBHP. Between populations, YBHP was closely related to the hairless pigs from Guadyerbas, USYU, and Canarias. Principal component analysis showed the same result. According to the results obtained from the runs of homozygosity investigation, aimed to get pools consensus of regions of overlapping, 119 SNPs associated with genes and biological processes were identified. The BMP7 and NSUN2 genes were associated with epithelial cell differentiation, morphogenesis, and epithelial development. For nutrient metabolism: energy, the HADHA, PPARA, ADD1/SREBF1, and FAT 1genes were identified.(AU)

Para realizar programas de conservação ex-situ de suínos crioulos, é importante determinar quais animais serão criados, preferencialmente aqueles com maior componente de genética ibérica, para preservar sua origem. Uma subpopulação de porco preto calvo de Yucatán (YBHP) foi usada para estimar sua diversidade genética e estrutura populacional. Um total de 104 suínos adultos foram selecionados levando-se em consideração características como ausência de pelos, pele preta (sem manchas), casco preto e focinho reto. O painel GGP-50K foi utilizado para a genotipagem dos SNPs em animais YBHP, e informações de porcos sem pelos ibéricos e de Yucatán dos Estados Unidos (USYU) foram retiradas de bancos de dados. Todas as análises foram realizadas com o software PLINK v1.9 e v2.1. Os valores dos índices de endogamia e fixação foram menores em YBHP, com altos valores de índice de heterozigosidade e alogamia observados, que concordam com os obtidos nas populações de Canárias e Chato Murciano. De acordo com os clusters gerados pela análise "Genoma-Wide Identity By State", quatro grupos foram identificados, um dos quais incluiu porcos de Guadyerbas, USYU e YBHP. Entre as populações, YBHP estava intimamente relacionado com os porcos sem pelo de Guadyerbas, USYU e Canárias. A análise de componentes principais mostrou o mesmo resultado. De acordo com os resultados obtidos nas corridas de investigação de homozigose, visando obter consenso de pools de regiões de sobreposição, foram identificados 119 SNPs associados a genes e processos biológicos. Os genes BMP7 e NSUN2 foram associados à diferenciação de células epiteliais, morfogênese e desenvolvimento epitelial. Para metabolismo de nutrientes: energia, os genes HADHA, PPARA, ADD1/SREBF1 e FAT1 foram identificados.(AU)

A molecular and morphological study of Ascaris suum in a human-pig contact scenario in northeastern Brazil / Estudo molecular e morfológico de Ascaris suum em um cenário de contato entre suínos e humanos no nordeste brasileiro

The aim of the present study was to assess morphologic and genetic data on ascariasis in swine (Sus scrofa domesticus) and humans in low-resource rural and periurban communities in the state of Piauí, Brazil. Our cross-sectional survey included 100 fecal samples obtained from swine and 682 samples from humans. Fifteen pigs were necropsied. Human and porcine fecal samples were examined to identify Ascaris eggs. Parasites obtained in the swine necropsies were studied using scanning electron microscopy (SEM), and the mitochondrial gene encoding the cytochrome oxidase 1 (cox1) enzyme was partially amplified and sequenced for molecular taxonomy and phylogenetic analyses. The overall prevalence of Ascaris eggs in the swine fecal samples was 16/100 (16%). No Ascaris eggs were identified in the human fecal samples. SEM of six worms recovered from pigs demonstrated morphological characteristics of A. suum. Cox1 sequences were compatible with A. suum reference sequences. Original and reference (GenBank) nucleotide sequences were organized into clusters that did not segregate the parasites by host species or and region. The largest haplogroups were dominated by haplotypes H01, H02 and H31. In the communities studied, there was no epidemiological evidence of the zoonotic transmission of ascariasis at the human-swine interface.(AU)

O presente estudo teve como objetivo acessar dados morfológicos e genéticos sobre a ascaridíase em suínos (Sus scrofa domesticus) e humanos, em comunidades rurais e periurbanas no estado do Piauí. O estudo transversal incluiu 100 amostras fecais de suínos e 682 amostras obtidas de humanos. Quinze suínos foram necropsiados. Amostras fecais suínas e humanas foram examinadas para detecção de ovos de Ascaris. Os parasitas adultos, obtidos nas necropsias, foram estudados através de microscopia eletrônica de varredura (MEV), e o gene mitocondrial codificante da enzima citocromo oxidase 1 (cox1) foi parcialmente amplificado e sequenciado para análises filogenéticas e de taxonomia molecular. A prevalência de Ascaris em amostras fecais de suínos foi 16/100 (16%), não sendo identificado nenhum caso de infecção por este parasita em humanos. A análise por MEV de parasitas recuperados de suínos demonstrou características morfológicas de Ascaris suum. As sequências nucleotídicas de cox1 foram compatíveis com A. suum. As sequências originais e de referência (obtidas no GeneBank) foram organizadas em clusters que não segregaram os parasitas por hospedeiro ou região geográfica. Os maiores haplogrupos foram dominados pelos haplótipos H01, H02 e H31. Nas comunidades estudadas, não foi evidenciada transmissão zoonótica de A. suum na interface suíno-humana.(AU)

Estimation of genetic parameters and inbreeding depression in Piau pig breed.

This study is aimed at estimating genetic parameters, effective population size, inbreeding, and inbreeding depression for birth weight, weaning weight, and average pre-weaning daily weight gain (ADG) in Piau pigs. We used information from 3841 Piau pigs, and four linear models were fitted in single-trait analyses, including or excluding maternal genetic effect, common litter effect, or a combination. The adjustments of the models were compared using the likelihood ratio test, in which the model that presented the best fit for each trait was used to estimate the (co)variance components. The inbreeding depression effect was evaluated using a linear model that included the fixed effects of sex, parity order, contemporary group, and inbreeding coefficient as a fixed covariate. The weights at birth and weaning showed low direct heritabilities (0.08 and 0.05, respectively), while the ADG showed moderate heritability (0.20). The weight at birth showed high genetic correlations with the weight at weaning (0.90) and the ADG (0.82). The weight at weaning and the ADG also showed a high genetic correlation (0.99). There was an inbreeding increase over the generations and a reduction in the effective population size. In the last generation evaluated, all the animals were inbred, the average inbreeding coefficient was 0.07, and the effective population size was 20.8. A significant inbreeding effect on ADG was observed, where an increase of 1% in the inbreeding coefficient resulted in a decrease of 0.005 g in the ADG. Thus, increasing effective population size is mandatory for controlling inbreeding and reducing the loss of variability in this Piau pig population.

Effects of feeding ractopamine hydrochloride with or without supplemental betaine on live performance, carcass and meat quality traits, and gene expression of finishing pigs.

The objective of this study was to evaluate the effects of ractopamine and betaine, supplemented alone or in combination, on live performance, carcass and meat quality traits, and gene expression (in both skeletal muscle and subcutaneous adipose tissue) of finishing pigs. Seventy-two pigs averaging 89.0 ± 3.44 kg were assigned to a control diet (CTRL-without ractopamine and betaine); CTRL+20 mg/kg ractopamine (RAC); CTRL+2.5 g/kg betaine (BET); or RAC + 2.5 g/kg betaine (RAC + BET). Pigs fed RAC and RAC + BET had greater average daily gain and carcass yield compared to CTRL. Pigs fed RAC, BET, and RAC + BET had greater loin muscle area, while backfat thickness was lower in pigs fed RAC + BET compared to CTRL. Pork from BET had lower shear-force and greater intramuscular fat content compared to CTRL. Regarding adipose tissue, RAC and BET increased expression of genes related to lipolysis and ß-oxidation. These data indicate that performance and carcass traits of pigs can be improved with ractopamine, whereas betaine (when fed independently from ractopamine) increased the loin muscle area and pork quality.

Housing Conditions and a Challenge with Lipopolysaccharide on the Day of Estrus Can Influence Gene Expression of the Corpus Luteum in Gilts.

The corpus luteum (CL) is a temporary endocrine gland that plays a decisive role in the reproductive physiology of gilts. Recently, it has been suggested that exogenous factors may compromise the normal functioning of the CL. In the present study, we aimed to understand to what extent an acute and systemic challenge with lipopolysaccharide (LPS) on the day of estrus could compromise gene expression of gilts' CLs housed in different welfare conditions. For this, we housed 42 gilts in three different housing systems: crates, indoor group pens, and outdoor housing. Then, we challenged six females from each group with LPS and eight with saline (SAL) on the day of estrus. After slaughtering the gilts on the fifth day after the challenge, ovaries were collected for gene expression analysis by RT-qPCR. Housing system and LPS challenge did not have a significant interaction for any genes evaluated; thus, their effects were studied separately. We identified significant (p < 0.05) downregulation of the angiogenic genes VEGF and FTL1 among LPS-challenged animals. Meanwhile, we also observed upregulation of HSD3B1 gene among LPS-challenged animals. We found that STAR and LHCGR genes were differentially expressed depending on the housing system, which indicates that the environment may affect adaptation capabilities. Our results indicate that an acute health challenge on the estrus day alters CL gene expression; however, the role of the housing system remains uncertain.

Influência da genética e dos métodos de conservação sobre a qualidade do sêmen suíno / Influence of genetics and conservation methods on the quality of swine semen

A demanda do mercado impulsionou o melhoramento genético na suinocultura caracterizado pelo cruzamento entre linhagens e raças distintas a fim de possibilitar o aproveitamento da heterose. Esse melhoramento acelerado ocorreu em decorrência da inseminação artificial e manipulação do sêmen, associado ao emprego de diluentes e técnicas de refrigeração. Sendo assim, esta revisão tem como objetivo compilar o conhecimento acerca da influência genética e dos métodos de conservação sobre a qualidade do sêmen suíno, além de discutir a composição e eficiência dos principais diluentes e crioprotetores destinados à conservação espermática nesta espécie. Inicialmente, os animais eram selecionados baseados em características produtivas como habilidade materna, qualidade de carcaça e desempenho. Contudo, a fertilidade do reprodutor, caraterizada pela qualidade espermática e libido, é extremamente importante para indústria suinícola uma vez que determina, o potencial produtivo do plantel indiretamente. Evidências demonstram que os parâmetros espermáticos sofrem influência da genética, sendo que cada raça se destaca numa determinada característica seminal. Além disso, o manejo, idade, alimentação, sazonalidade, as características intrínsecas do espermatozoide e os métodos de conservação do ejaculado também determinam sua viabilidade. Apesar de preconizado devido à fácil execução e ótimos resultados, o sêmen refrigerado tem como limitador a produção excessiva de espécies reativas de oxigênio. Da mesma forma, o congelamento do ejaculado promove alterações espermáticas em virtude do choque térmico. Sendo assim, o emprego de diluentes e crioprotetores propícios que possibilitem a manutenção a longo prazo da viabilidade espermática é imprescindível para ambos os processos.

The market demand promoted the genetic improvement in swine farming characterized by the crossing between different strains and breeds to make possible the use of heterosis. This accelerated improvement occurred due to artificial insemination and semen manipulation, associated with the use of extenders and refrigeration techniques. Therefore, this review aims to compile knowledge about the genetic influence and conservation methods on the quality of swine semen, besides to discussing the composition and efficiency of the main extenders and cryoprotectants intended for sperm conservation in this species. Initially, animals were selected based on productive traits such as maternal ability, carcass quality, and performance. However, male fertility, characterized by sperm quality and libido, is extremely important for the swine industry as it determines the productive potential of the herd indirectly. Evidences demonstrates that sperm parameters are influenced by genetics, with each race standing out in certain seminal trait. In addition, the management, age, feeding, seasonality, the intrinsic characteristics of the sperm cell, and the methods of ejaculate conservation also determine its viability. Despite being recommended due to its easy execution and excellent results, refrigerated semen has the excessive production of reactive oxygen species as a limiter. Likewise, the ejaculate freezing promotes sperm changes due to heat shock. Therefore the use of suitable extenders and cryoprotectants that allow the long-term maintenance of sperm viability is essential for both processes.

From Mendel laws to whole genetic association study to decipher the swine mulefoot phenotype.

The swine mulefoot (SM) is a rare condition characterized by a non-cloven hoof due to the partial or total fusion of the phalanges. No comprehensive study has been conducted to identify associated markers with this phenotype until now. We aimed to characterize the association between SNP and the mulefoot phenotype using a Genome-Wide Association Study (GWAS). An experimental population was produced using a half-sib mating where the male had the mulefoot phenotype and the females (n = 6) had cloven hoofs. The cross resulted in 27 (47%) animals with the mulefoot characteristic and 30 (53%) normal animals, indicating the possible dominant gene action. Animals were further genotyped using the Illumina PorcineSNP50k BeadChip, and SNPs were tested for associations. Twenty-nine SNPs located on the SSC15, SSC4, and SSCX were associated with the mulefoot phenotype (p-value <5 × 10-5). Six markers were found in the intronic regions of VWC2L, CATIP, PDK3, PCYT1B, and POLA1 genes. The marker rs81277626, on SSC15:116,886,110 bp, is located in the Von Willebrand Factor C Domain (VWC2L), a possible functional candidate gene. The VWC2L is part of a biological process involved with the bone morphogenetic protein (BMP) signaling pathway, previously associated with syndactyly in other species. In conclusion, the identified markers suggest the involvement of the VWC2L gene in the SM phenotype in this population.

Cytochrome c oxidase subunit 1 gene reveals species composition and phylogenetic relationships of Oesophagostomum spp. infecting pigs in northeastern Brazil / Inferências filogenéticas e caracterização de Oesophagostomum spp. parasitos de suínos no estado do Piauí, Brasil, por sequenciamento parcial de DNA mitocondrial

Helminths of the genus Oesophagostomum cause enteric diseases and affect domestic animals such as pigs. The aim of this study was to explore the species composition and genetic diversity of Oesophagostomum spp. infecting pigs in close contact with humans in the state of Piauí, Brazil. Eighty-seven fecal samples were collected for parasitological tests and molecular analysis. Through microscopy, the overall positivity rate for strongyliform eggs was 81.6% among the pigs studied. Forty-two strongyliform egg samples were subjected to PCR and six cox1 sequences (637 bp) were identified for the genus Oesophagostomum. The sequences were identified as Oesophagostomum dentatum, O. quadrispinulatum and O. columbianum. In the phylogenetic tree and haplotype network, 89 sequences were separated into seven clusters, which also included reference sequences from GenBank. Oesophagostomum dentatum and O. quadrispinulatum were seen to be closely related species and formed a monophyletic group related to O. aculeatum. Oesophagostomum columbianum showed similarity with sequences from parasites infecting small ruminants and the clade was positioned closer to O. bifurcum. High interspecific diversity was found and intraspecific diversity varied according to the species. This was the first study to characterize Oesophagostomum DNA sequences obtained from pigs in Brazil.(AU)

Parasitos do gênero Oesophagostomum causam doenças entéricas e podem afetar a criação de animais, como os suínos. O objetivo deste estudo foi identificar as espécies e explorar a diversidade genética de Oesophagostomum spp. infectando suínos em contato próximo com humanos, no estado do Piauí, Brasil. Oitenta e sete amostras fecais foram coletadas para testes parasitológicos, análise morfométrica dos ovos e análises moleculares. A taxa geral de positividade para ovos estrongiliformes foi de 81,6%. Quarenta e duas amostras de ovos estrongiliformes foram submetidas à PCR e seis sequências cox1 (637 bp) foram identificadas para o gênero Oesophagostomum. As sequências foram identificadas como Oesophagostomum dentatum, O. quadrispinulatum e O. columbianum. Na árvore filogenética e na rede haplotípica, 89 sequências foram separadas em sete clusters, incluindo sequências de referência do GenBank. Oesophagostomum dentatum e O. quadrispinulatum são espécies estreitamente relacionadas e formaram um grupo monofilético com O. aculeatum. Oesophagostomum columbianum apresentou semelhança com sequências de parasitas obtidos de pequenos ruminantes e o clado foi posicionado mais próximo de O. bifurcum. Alta diversidade interespecífica foi encontrada e a diversidade intraespecífica variou de acordo com as espécies. Esse foi o primeiro estudo a caracterizar sequências de DNA de Oesophagostomum isoladas de suínos no Brasil.(AU)

A joint analysis using exome and transcriptome data identifiescandidate polymorphisms and genes involved with umbilical hernia in pigs.

BACKGROUND: Umbilical Hernia (UH) is characterized by the passage of part of the intestine through the umbilical canal forming the herniary sac. There are several potential causes that can lead to the umbilical hernia such as bacterial infections, management conditions and genetic factors. Since the genetic components involved with UH are poorly understood, this study aimed to identify polymorphisms and genes associated with the manifestation of umbilical hernia in pigs using exome and transcriptome sequencing in a case and control design. RESULTS: In the exome sequencing, 119 variants located in 58 genes were identified differing between normal and UH-affected pigs, and in the umbilical ring transcriptome, 46 variants were identified, located in 27 genes. Comparing the two methodologies, we obtained 34 concordant variants between the exome and transcriptome analyses, which were located in 17 genes, distributed in 64 biological processes (BP). Among the BP involved with UH it is possible to highlight cell adhesion, cell junction regulation, embryonic morphogenesis, ion transport, muscle contraction, within others. CONCLUSIONS: We have generated the first exome sequencing related to normal and umbilical hernia-affected pigs, which allowed us to identify several variants possibly involved with this disorder. Many of those variants present in the DNA were confirmed with the RNA-Seq results. The combination of both exome and transcriptome sequencing approaches allowed us to better understand the complex molecular mechanisms underlying UH in pigs and possibly in other mammals, including humans. Some variants found in genes and other regulatory regions are highlighted as strong candidates to the development of UH in pigs and should be further investigated.