Development In Swine Research Articles

8 Gestational heat stress: Implications for pregnancy success and offspring development in swine

8 Gestational heat stress: Implications for pregnancy success and offspring development in swine

130 Parity affects mammary development in late-pregnant swine

Abstract This project was undertaken to determine if mammary development at the end of gestation differs between primiparous and multiparous sows. During gestation, primiparous (n = 19) and multiparous (parities 2 and 3, n = 17) Yorkshire × Landrace sows were fed one daily meal of a conventional corn-based diet. Amounts fed were based on body weight (BW) and backfat thickness at mating. On d 110 ± 1 of gestation, a jugular blood sample was obtained from all sows to measure IGF-1, glucose, FFA and urea. Sows were then weighed and their backfat thickness measured before euthanasia. Mammary glands from one side of the udder (7 glands) were dissected for compositional analyses. The fifth gland of the contralateral row of mammary gland was sampled for histology and immunohistochemical localization of Ki67. There was less total parenchyma (1,437.4 vs 2,004.7 ± 127.1 g) and total extra-parenchymal tissue (1,691.0 vs 2,407.0 ± 125.3 g; P < 0.001) in mammary gland of primiparous compared with multiparous sows. When these values were expressed per kg BW (respective means of 226.0 and 284.0 ± 2.7 kg for primiparous and multiparous sows), there was no difference for either parenchyma or extra-parenchymal tissue across parity groups (P > 0.05). Parity altered all components within the parenchyma (P < 0.001). Specifically, parenchymal tissue from primiparous sows had greater fat and DM percentages, decreased protein percent, and reduced concentrations of DNA (6.59 vs 9.35 ± 0.53 mg/g DM) and RNA (7.76 vs 12.33 ± 0.70 mg/g DM) than that from multiparous sows. On the other hand, the circumference of alveolar lumens was greater in primiparous than multiparous sows (P < 0.001), and the percentage of epithelial cells that were positive for Ki67, an indicator of cell proliferation, also tended to be greater in primiparous sows (P = 0.07). Circulating concentrations of IGF-1 were greater in primiparous than multiparous sows (45.0 vs 27.3 ± 2.8 ng/mL, P < 0.001). None of the other blood variables were affected by parity (P > 0.10). Results show a marked effect of parity on mammary gland development in swine. At the end of gestation, primiparous sows had less developed mammary parenchyma with a tendency for a greater rate of proliferation than multiparous sows. Such a difference could affect the response of mammary tissue to various nutritional or endocrine signals. This information is crucial for developing optimal management strategies that will maximize sow milk yield.

Identification of SWI/SNF Subcomplex GBAF Presence, Intra-Complex Interactions, and Transcriptional Dynamics during Early Porcine Development.

Understanding the complex interplay between genetics and environmental factors is vital for enhancing livestock production efficiency while safeguarding animal health. Despite extensive studies on production-specific genes in livestock, exploring how epigenetic mechanisms and heritable modifications govern animal growth and development remains an under-explored frontier with potential implications across all life stages. This study focuses on the GBAF chromatin remodeling complex and evaluates its presence during embryonic and fetal development in swine. Immunocytochemistry and co-immunoprecipitation techniques were employed to investigate the presence and interactions of GBAF subunits BRD9 and GLTSCR1 in porcine oocytes, preimplantation embryos, and cell lines, and transcriptional dynamics of GBAF subunits across these key developmental stages were analyzed using existing RNA-seq datasets. BRD9 and GLTSCR1 were identified across all represented stages, and an interaction between GLTSCR1 and BAF170 was shown in PTr2 and PFF cells. Our findings highlight the ubiquitous presence of GBAF in porcine early development and the potentially novel association between GLTSCR1 and BAF170 in swine. The transcriptional dynamics findings may suggest GBAF-specific contributions during key developmental events. This study contributes to the growing understanding of epigenetic regulators in both swine and mammalian development, emphasizing the implications of GBAF as a modulator of key developmental events.

Parity affects mammary development in late-pregnant swine.

The goal of this project was to determine whether various measures of mammary development differed between gilts and multiparous sows at the end of gestation. During gestation, Yorkshire × Landrace gilts (n = 19) and sows (second and third gestations, n = 17) were fed one daily meal of a conventional corn-based diet, where the amount fed was based on body weight (BW) and backfat thickness (BF) at mating. On day 110 ± 1 of gestation, a jugular blood sample was obtained from all gilts and sows to measure insulin-like growth factor-1 (IGF-1), glucose, free fatty acids, and urea. On that same day, BW and BF were measured and animals were euthanized. Mammary glands from one side of the udder were dissected for compositional analyses. The fifth gland of the contralateral row of mammary glands was sampled for histology and immunohistochemical localization of Ki67. There was less total parenchyma (1,437.4 vs. 2,004.7 ± 127.1g; P < 0.001) and total extraparenchymal tissue (1,691.0 vs. 2,407.0 ± 125.3g; P < 0.001) in mammary glands of gilts compared to those from sows. When these values were expressed per kg BW (226.0 and 284.0 ± 2.7kg for gilts and sows, respectively), parenchymal mass did not differ (P > 0.10), while extraparenchymal tissue weight tended to be less in gilts than sows (P = 0.07). All components within the parenchyma differed by parity (P < 0.001). Specifically, parenchymal tissue from gilts contained a greater proportion of fat and dry matter (DM), a lower proportion of protein, and lower concentrations of DNA (6.59 vs. 9.35 ± 0.53mg/g DM) and RNA (7.76 vs. 12.33 ± 0.70mg/g DM) than that from sows. On the other hand, the circumference of alveolar lumens was greater in gilts than sows (P < 0.001), while the percentage of epithelial cells that were positive for Ki67, a marker of cell proliferation, was greater in sows than gilts (P < 0.05). Circulating concentrations of IGF-1 were greater in gilts than in multiparous sows (45.0 vs. 27.3 ± 2.8ng/mL, P < 0.001). None of the other blood variables were changed by parity. Results show a marked effect of parity on mammary gland development in swine. At the end of gestation, the mammary glands of gilts had less parenchyma with lower epithelial proliferation than glands from multiparous sows. These differences could alter the response of mammary tissue to various nutritional or endocrine signals. This information is crucial for the development of management strategies designed to maximize sow milk yield.

Compensatory mechanisms in response to induced hypothyroidism in the late gestation pig fetus†.

To understand the effect of fetal thyroid gland disruption on development in swine, we evaluated thyroid hormone levels, growth and developmental characteristics, and gene expression associated with thyroid hormone metabolism in late gestation fetuses exposed to methimazole (MMI). Pregnant gilts were given either oral MMI or equivalent sham from gestation day 85-106 (n= 4/group), followed by intensive phenotyping of all fetuses (n= 120). Samples of liver (LVR), kidney (KID), fetal placenta (PLC), and the corresponding maternal endometrium (END) were collected from a subset of fetuses (n= 32). Fetuses exposed to MMI in utero were confirmed hypothyroid, with a significant increase in thyroid gland size, goitrous thyroid histology, and dramatically suppressed thyroid hormone in serum. In dams, no differences in temporal measurements of average daily gain, thyroid hormone, or rectal temperatures relative to controls suggests that MMI had little effect on maternal physiology. However, fetuses from MMI-treated gilts exhibited significant increases in body mass, girth, and vital organ weights, but no differences in crown-rump length or bone measurements suggesting non-allometric growth. The PLC and END showed a compensatory decrease in expression of inactivating deiodinase (DIO3). Similar compensatory gene expression was observed in fetal KID and LVR with a downregulation of all deiodinases (DIO1, DIO2, DIO3). Minor alterations in the expression of thyroid hormone transporters (SLC16A2 and SLC16A10) were observed in PLC, KID, and LVR. Collectively, MMI crosses the PLC of the late gestation pig, resulting in congenital hypothyroidism, alterations in fetal growth, and compensatory responses within the maternal fetal interface.

Vitamin C Deficiency Causes Hematological and Skeletal Abnormalities during Fetal Development in Swine

The influence of maternal vitamin C deficiency on fetal development was studied in swine with a hereditary lack of ability to synthesize ascorbic acid (OD pigs). Thirteen pregnant sows homozygous (od/od) for the defect were depleted of ascorbic acid for 24 to 38 d at various stages of gestation. Six normal (OD/OD) sows were used as controls. Only a few experimental sows showed clinical symptoms of vitamin C deficiency. Nevertheless, severe pathological changes were seen in the uterus and fetuses. Characteristic findings were hemorrhages and hematomas in both fetal and maternal placenta, and general edema and subcutaneous hemorrhages in the fetuses. Similarities were noted to the abruptio placentae syndrome in women. Depletion of vitamin C resulted in a pronounced decline in ascorbic acid concentration in most maternal and fetal organs as well as in plasma and embryonic fluids. No morphological malformations were found in the fetuses, but the ossification of the skeleton was severely deranged. Macroscopically the lesions comprised swelling of the costochondral junction and separation of the epiphysial cartilage from the spongiosa in ribs and limb bones. Another characteristic finding was loosening of the periost from the cortex, often resulting in subperiosteal bleedings. Microscopically normal osteoblasts were few and the formation of osteoid defective.

Prolactin and the swine mammary gland

Prolactin is a hormone that is most important for mammary development in swine. It is also essential for both the onset and the maintenance of lactation. In early studies, exogenous recombinant porcine prolactin was used to detect its biological effects on mammary tissue. In these studies, a stimulatory role of prolactin for mammary development of prepubertal gilts was demonstrated. However, when injected throughout lactation, prolactin did not increase sow milk yield likely because mammary receptors were saturated. The secretion of prolactin is largely under negative regulation via dopamine. Inhibition studies using the dopamine agonist bromocriptine showed that prolactin is required in the last third of gestation to sustain mammary development in gilts. When creating a hyperprolactinemic state during that same period, with the dopamine antagonist domperidone, differentiation of mammary epithelial cells was stimulated and milk yield in the subsequent lactation was increased. Domperidone given throughout lactation also led to greater milk yield. A study using domperidone in prepubertal gilts, however, did not reproduce the stimulatory effect of exogenous prolactin on mammary development and demonstrated that timing of the prolactin increase in relation to age of the animals is most important to elicit a response on mammary tissue. Attempts were made to use feed ingredients such as the plant extract from milk thistle, sylimarin, to stimulate prolactin secretion in sows. However, even though prolactin concentrations were increased, this augmentation was not important enough to have an impact on mammary development in late gestation or to increase milk yield. The current knowledge that hyperprolactinemia has beneficial effects for mammary development at various physiological stages and can enhance milk yield in swine leads to new avenues in elaborating strategies that could be used at the farm level to improve sow lactation performance.

PSV-10 Effects of l-α-amino Butyrate Supplementation on Oocyte Maturation

Abstract L-α-amino butyrate is a low-molecular weight thiol compound that acts to increase the levels of glutathione in the oocyte. Glutathione acts as an antioxidant during oocyte maturation and promotes male pronuclear formation during fertilization. Supplementing the L-α-amino butyrate helps to decrease polyspermic penetration rates and improve early embryonic development in swine. However, it is unknown if L-α-amino butyrate supplementation affects the environment of the oocyte or the oocyte directly. Therefore, the objective of this study was to determine if L-α-amino butyrate supplementation to the maturation media acted on the oocyte or had alternative beneficial effects in the surrounding environment. Oocytes were randomly assigned to a maturation media containing an amino acid transport inhibitor, quisqualic acid (QA) (0 or 1 mM) and then supplemented with L-α-amino butyrate (0 or 3.3 mM). Oocytes were evaluated for stage of meiosis (n=380) and cumulus cell expansion (n=411) at the end of maturation. The remaining oocytes were fertilized and evaluated for cortical granule exocytosis (n=400) and IVF kinetics (n=456). Supplementation of L-α-amino butyrate with or without QA significantly increased (P &amp;lt; 0.05) cumulus cell expansion, cortical granule exocytosis and male pronuclear formation compared to no supplementation or QA supplementation. There was no difference in meiotic progression, fertilization or polyspermic penetration rates between the treatment groups. Results suggest that when L-α-amino butyrate is supplemented during maturation, it improves the maturation of the oocyte by acting directly on the oocyte and not through the surrounding environment of the oocyte.

CD200R1 and CD200R1L expression is regulated during B cell development in swine and modulates the Ig production in response to the TLR7 ligand imiquimoid.

The CD200R family comprises a group of paired receptors that can modulate the activation of immune cells. They are expressed both on myeloid cells and lymphocyte subsets. Here we report that the expression of these receptors on porcine B cells is tightly regulated, being mainly expressed on mature cells. The expression of the inhibitory receptors CD200R1 and/or its splicing variant CD200R1X2, either in combination or not with the activating receptor CD200R1L, is upregulated in sIgM+ effector/memory cells, and tends to decline thereafter as these cells progress to plasmablasts or switch the Ig isotype. sIgM+ naïve and primed cells only express, by contrast, the CD200R1X2 receptor. B-1 like cells also express CD200R1 isoforms, either alone or in combination with CD200R1L. Treatment of peripheral blood mononuclear cells with a monoclonal antibody specific for inhibitory receptors, enhances the IgM and IgG production induced by TLR7 stimulation suggesting a modulatory role of B cell functions of these receptors.

Temporal microRNA expression profile of pig peripheral blood during postnatal development

Gene expression profiles of blood can reflect the physiopathologic status of the immune system. The dynamic microRNA (miRNA) expression profiles of peripheral blood from pigs at different developmental stages, and how differential expression of miRNAs might relate to immune system development, are unknown. In this study, peripheral blood samples taken at five developmental stages were used to construct 15 miRNA libraries (three biological replicates/stage): 0 days (newborn), 30 days (weaning), 60 days (weaned), and 180 and 360 days (puberty). We identified 295 known mature miRNAs. Hierarchical clustering of the miRNA expression profile showed significant differences between individuals at the neonatal and postnatal stages. Functional enrichment analysis revealed that miRNAs differentially expressed between pairwise comparisons of the developmental stages were over-represented in immune-related pathways such as toll-like receptor signaling. The time-course of expression of the over-representated miRNAs exhibited a pattern of steady decline over time, for both the complete miRNA compendium and immune-related miRNAs. We identified six marker miRNAs that were highly negatively correlated with chronologic age and enriched for genes involved in immune-related pathways. This study of a peripheral blood miRNA transcriptome offers insight into immune system development in swine and provides a resource for pig genome annotation.

Functional genomic approaches for the study of fetal/placental development in swine with special emphasis on imprinted genes

Functional genomic approaches for the study of fetal/placental development in swine with special emphasis on imprinted genes

Development of Swine's Digestive Tract Microbiota and Its Relation to Production Indices-A Review.

Simple SummaryProper cooperation between digestive system microbiota and the host is an important issue in maintaining proper health condition, and—in the case of farm animals—production indices. In the case of pigs, microbiota significantly affect production parameters such as meat quality, growth rate or improvement of immune response to infections. Understanding of pig digestive system microbiota and factors affecting this is an important issue. This may enable improvement of animal performance and stabilization of microbiota during their growth, reducing the risk of metabolic or systemic diseases.The development of research methods and tools related to microbiome investigation, as well as widened knowledge and awareness concerning the significance of microorganisms inhabiting mammalian organisms, has led to an increasing popularity of studies in this field. This review paper presents some issues related to the swine microbiome, its development starting from an early age of life and its status in adult animals, as well as factors affecting the microbiome in pigs. Attention is paid to the role of probiotics and prebiotics as alternatives to antibiotics in the context of post-weaning diarrhea treatment, and to the role of microorganisms inhabiting the digestive tract of pigs in performance indices formation. In veterinary and pork production practice, understanding of the swine microbiome and its relationships with the host organism may be useful in the prevention of some diseases and also in improvement of performance results of animals.

The use of microarrays to define functionally-related genes that are differentially expressed in the cycling pig uterus

In swine and other livestock, the uterine endometrium exhibits dramatic morphological and secretory changes throughout the oestrous cycle and during pregnancy. Such physiological changes are a reflection of extremely complex interactions between gene products (RNA and protein). The recent development of genomics and proteomics methods, as well as associated bioinformatics tools, has provided the means to begin characterising such interactions. Indeed, the analysis of the transcriptome and proteome of cells and tissues now comprises a new field of study known as 'systems biology'. Currently, the most powerful technique available to the systems biologist is the microarray. These platforms represent oligonucleotide or cDNA fragments spotted in a specified high-density pattern on a solid support. Hybridisation of fluorescently-tagged cDNAs from different tissue sources permits the measurement of thousands of RNAs in parallel. The method permits the identification of genes that are present at different amounts between the two tissues and, more importantly, it permits the identification of groups of genes (clusters) that are expressed in comparable patterns. Results from a recent expression profiling experiment are described. The goal of the profiling experiment was to define genes that are differentially expressed in endometrium during the oestrous cycle. The experiment used an in-house cDNA microarray with >14,000 distinct cDNAs cloned from reproductive tissues. Total RNAs from cyclic endometrium (Days 0, 3, 6, 10, 12, 14 and 18 post-oestrus) were reverse transcribed into cDNAs, labelled with fluorescent dye and hybridised to the arrays along with cDNAs derived from a reference RNA pool. A total of 4,827 genes were found to differ significantly at some time during the oestrous cycle. Clustering methods were able to define numerous groups of similarly expressed genes. These data will help to define the complex patterns of endometrial genes acting in concert to create the environments required for fertilisation, embryo growth and conceptus development in swine.

Infection in xenotransplantation: opportunities and challenges.

Posttransplantation infections are common. It is anticipated that infection will be no less common in xenotransplantation recipients. Prolonged xenograft survivals have resulted from advances in immunosuppressive strategies and development of swine that decrease host immune responses via genetic manipulation, notably CRISPR/cas9 manipulation. As prospects for clinical trials improve, consideration of the unique infectious risks posed by xenotransplantation reemerge. Organisms likely to cause infection in human recipients of porcine xenografts are unknown in advance of clinical trials. Microbiological screening of swine intended as xenograft donors can be more intensive than is currently feasible for human allograft donors. Monitoring infection in recipients will also be more intensive. Key opportunities in infectious diseases of xenotransplantation include major technological advances in evaluation of the microbiome by unbiased metagenomic sequencing, assessments of some risks posed by porcine endogenous retroviruses (PERVs) including antiretroviral susceptibilities, availability of swine with deletion of genomic PERVs, and recognition of the rapidly changing epidemiology of infection in swine worldwide. Unknown infectious risks in xenotransplantation requires application of advanced microbiological techniques to discern and prevent infection in graft recipients. Clinical trials will provide an opportunity to advance the safety of all of organ transplantation.

83 Lifelong dynamics of the swine gut microbiome: from birth to market

Abstract Despite the recent advances in the swine gut microbiomes during different growth stages, a comprehensive longitudinal study of the lifelong dynamics of the swine gut microbiome is lacking. To fill this gap of knowledge, we selected seventeen piglets (PIC29*380) that were born on the same date from three sows. We collected a total of 274 rectal swabs during lactation (d 0, 11, 20), nursery (d 27, 33, 41, 50, 61), growing (d 76, 90, 104, 116), and finishing (d 130, 146, 159, and 174) stages. Samples were extracted using the Powersoil DNA isolation kit (Qiagen, Hilden, Germany) and sequenced with an Illumina Miseq sequencer targeting the V4 region of the 16 S rRNA gene. Sequences were analyzed with the Deblur algorithm in the QIIME2 package. In general, alpha diversity including community richness (e.g., number of observed features, Chao1) and diversity (e.g., Shannon Index) showed an overall trend of increasing from lactation to the finishing stage (P &lt; 0.01). Gradual and significant changes in community structures were also observed along the four growth stages (ANOSIM, R = 0.66; P &lt; 0.01). Non-parametric permutational multivariate analysis of variance shows that main factors driving the lifelong community dynamics included age and diet. Seventeen phylum members were discovered in the lifelong pig gut microbiome with Firmicutes and Bacteroidetes being the most abundant phyla. LEfSe analysis revealed 63 bacterial features that are stage specific. By using a regressing tree based Random Forest model we identified five bacterial features that are associated with swine growth performance including features 26 (Turicibacteraceae Turicibacter), 27 (Clostridium butyricum), 18 (Clostridiaceae), 19 (Clostridium perfringens) and 4 (Clostridiaceae). Characterization of the lifelong dynamics of 17 healthy pigs from birth to market provides a foundation for gut microbiome studies focusing on swine development, health and growth performance.

Abstract 334: Collateral Development in Swine after Ligation of Native Leg Arteries

Introduction: The development of collateral vasculature is a key mechanism compensating for arterial occlusions in patients with Peripheral Artery Disease (PAD). We aimed to examine the development of collateral pathways after ligation of native vessels in a porcine model of PAD. Methods: Right hindlimb ischemia was induced in domestic swine (N=11, male, 26-57 kg) using two different versions of arterial ligation. Version 1 (N=6) consisted of ligation/division of the right external iliac, profunda femoral (RPFA) and superficial femoral arteries (RSFA). Version 2 (N=5) consisted of the ligation of Version 1 with additional ligation/division of the right internal iliac artery (RIIA). Development of collateral pathways was evaluated with standard angiography at baseline (prior to arterial ligation) and at termination (4-8 weeks later). Relative luminal diameter of the arteries supplying the ischemic right hindlimb were determined by 2D angiography, as percent of the size of the distal aortic diameter. Results: The pathway connecting the RIIA to the RPFA and RSFA/popliteal artery of the ischemic limb was the dominant collateral pathway in version 1. Mean luminal diameter (± standard error) of the RIIA at termination increased by 39.4± 5.5% (P&lt;0.01) compared to baseline. There were two co-dominant collateral pathways in version 2. The first pathway connected the common internal iliac trunk and left internal iliac artery to the reconstituted RIIA which then supplied the RPFA and RSFA/popliteal arteries. The second pathway connected the left profunda artery to the reconstituted RPFA. Mean diameter (± standard error) of the common internal iliac trunk and left profunda artery increased at termination by 23.7± 7.6% and 24.8± 7.4%, respectively (p &lt; 0.05). Conclusion: Two versions of hindlimb ischemia induction (right ilio-femoral artery ligation with and without right internal iliac artery ligation in swine produced differing collateral pathways along with changes to the diameter of the inflow vessels. Radiographic and anatomical data of the collateral formation in this porcine model has value in investigation of the pathophysiology of hindlimb ischemia, and assessment of angiogenic therapies as potential treatments for PAD.

SCAPs Regulate Differentiation of DFSCs During Tooth Root Development in Swine

The tooth root transmits and balances occlusal forces through the periodontium to the alveolar bone. The periodontium, including the gingiva, the periodontal ligament, the cementum and the partial alveolar bone, derives from the dental follicle (DF), except for the gingiva. In the early developmental stages, the DF surrounds the tooth germ as a sphere and functions to promote tooth eruption. However, the morphological dynamics and factors regulating the differentiation of the DF during root elongation remain largely unknown. Miniature pigs are regarded as a useful experimental animal for modeling in craniofacial research because they are similar to humans with respect to dentition and mandible anatomy. In the present study, we used the third deciduous incisor of miniature pig as the model to investigate the factors influencing DF differentiation during root development. We found that the DF was shaped like a crescent and was located between the root apical and the alveolar bone. The expression levels of WNT5a, β-Catenin, and COL-I gradually increased from the center of the DF (beneath the apical foramen) to the lateral coronal corner, where the DF differentiates into the periodontium. To determine the potential regulatory role of the apical papilla on DF cell differentiation, we co-cultured dental follicle stem cells (DFSCs) with stem cells of the apical papilla (SCAPs). The osteogenesis and fibrogenesis abilities of DFSCs were inhibited when being co-cultured with SCAPs, suggesting that the fate of the DF can be regulated by signals from the apical papilla. The apical papilla may sustain the undifferentiated status of DFSCs before root development finishes. These data yield insight into the interaction between the root apex and surrounding DF tissues in root and periodontium development and shed light on the future study of root regeneration in large mammals.

Antibody Repertoire Development in Swine

We describe the domestication of the species, explore its value to agriculture and bioscience, and compare its immunoglobulin (Ig) genes to those of other vertebrates. For encyclopedic information, we cite earlier reviews and chapters. We provide current gene maps for the heavy and light chain loci and describe their polygeny and polymorphy. B-cell and antibody repertoire development is a major focus, and we present findings that challenge several mouse-centric paradigms. We focus special attention on the role of ileal Peyer's patches, the largest secondary lymphoid tissues in newborn piglets and a feature of all artiodactyls. We believe swine fetal development and early class switch evolved to provide natural secretory IgA antibodies able to prevent translocation of bacteria from the gut while the bacterial PAMPs drive development of adaptive immunity. We discuss the value of using the isolator piglet model to address these issues.

327 Gonadotropin-releasing hormone II receptor (GnRHR-II) knockdown reduces testis size and decreases testosterone secretion during pubertal development in swine

327 Gonadotropin-releasing hormone II receptor (GnRHR-II) knockdown reduces testis size and decreases testosterone secretion during pubertal development in swine

B cell lymphogenesis in swine is located in the bone marrow.

A course and a site of B cell development in swine are not firmly known. In this study, we show that B cell lymphogenesis is located in the bone marrow (BM). According to expression of MHC class II (MHC-II), CD2, CD21, CD25, CD45RC, CD172a, swine workshop cluster (identification number) (SWC) 7, and μHC, porcine BM cells were resolved into seven subsets representing sequential stages of development. Profile of rearrangement-specific products and transcripts from sorted BM cells confirmed the proposed developmental pathway. The same developmental pathway was further proven by analysis of selection for productive rearrangements in Ig H chains and also by cultivation studies. Cultivation also showed that earliest precursors with incomplete DJ rearrangements can still revert their B cell differentiation and develop along myeloid lineage, whereas this is impossible for later developmental stages. Proliferation and the apoptotic potential of individual developmental stages as well as critical checkpoints were also identified. Colocalization experiments showed early colocalization of MHC-II/CD2/CD172a is replaced by colocalization of MHC-II/CD2/CD21/SWC7/IgM in immature cells, whereas CD25 and CD45RC did not colocalize with any other studied molecules. In this study, we also finally prove that the BM in pigs is fully functional in adult animals and that B lymphogenesis occurs there throughout life. To our knowledge, this is the first study showing a course and a direct site of B cell lymphogenesis in swine.