Boar Reproductive Tract Research Articles

PSIII-17 Relationship of toll-like receptor abundance in the boar reproductive tract with dihydrotestosterone prior to attainment of puberty

Abstract Fertile sperm production is crucial to the reproductive efficiency of swine operations; therefore, many factors impair quality semen production including hormonal imbalance and altered immune function. Toll-like receptors (TLRs) are a family of pattern recognition receptors which recognize and protect their host against pathogenic microorganisms through the regulation of inflammatory pathways. Recent data from our lab demonstrated greater expression of TLR2 mRNAs in the testes compared with other reproductive tissues (e.g., epididymis, seminal vesicles, and prostate) of pre-pubertal boars, suggesting TLR2 may aid early-in-life testes function or development. Expression of TLRs in various tissues has been shown to be influenced by hormones in rodents and humans. Dihydrotestosterone (DHT) is a sex steroid hormone and androgen that has a role in sexual development of males. However, little research has related TLRs with hormone concentration, which may help give insight to their physiological significance, particularly in the pre-pubertal male. Therefore, the objective of this project was to characterize relationships between expression of extracellular TLRs (TLR2, TLR4, TLR5 and TLR6) in the reproductive tissues (testes, epididymis, seminal vesicles, and prostate) with DHT concentrations in pre-pubertal boars. Intact reproductive tracts of pre-pubertal crossbred boars (Duroc x Landrace x Yorkshire; n = 4) were harvested at 2 mo of age and tissues were stored at –80°C for RT-qPCR analysis. From each boar, blood was collected postmortem and subsequent plasma samples stored at –20°C. Concentration of DHT in boar plasma was quantified using a competitive ELISA (MyBioSource, San Diego, CA) according to the manufacturer’s instructions. Expression of TLR2, TLR4, TLR5, and TLR6 mRNAs in the pre-pubertal boar tissues were quantified by RT-qPCR. Correlations of DHT concentration and TLR expression were calculated using Pearson Correlation within the PROC CORR function in SAS 9.4. The mean concentration of DHT was 9.32 ng/mL (range of 4.52 to 14.80 ng/mL). In the seminal vesicles, DHT concentration was significantly correlated with expression of both TLR2 (r = 0.95; P = 0.05) and TLR4 (r = 0.96; P = 0.04). In the testes, there was a tendency for a positive correlation between DHT concentration and expression of TLR2 mRNA (r = 0.92; P = 0.08). However, there were no correlations between DHT concentration and expression of any TLRs in the pre-pubertal boar epididymis or prostate (P > 0.10). These results suggest a relationship between androgens and TLR expression, particularly TLR2 and TLR4 mRNAs, in specific reproductive tissues of the pre-pubertal boar. Additional work will investigate TLR expression and androgen concentration in the pubertal boar.

PSI-12 Characterization of Boar Reproductive Tract Microbiome Prior to Puberty Attainment

Abstract A large portion of microbiome research has focused on characterization of the gastrointestinal tract and female reproductive tract. However, minimal research has focused on establishing the bacterial community in other organs, specifically male reproductive tissues and gonads. Characterization of these microbiomes in early life could be an indicator of future semen microbiome composition and subsequent fertility status. The aim of this study was to characterize the bacterial communities of various male reproductive tissues including the testes, epididymis, seminal vesicles, prostate, bulbourethral glands, and preputial diverticulum in pre-pubertal boars. Crossbred boars (n = 4), fed a conventional diet (20% crude protein), were euthanized at approximately 2 months of age, and their intact reproductive tracts were removed. For each tissue (testes, epididymis, seminal vesicles, prostate, bulbourethral glands, and preputial diverticulum), a small incision was made before a sterile swab was rotated several times and placed into a sterile microcentrifuge tube for further analysis. A sterile swab was exposed to the environment and placed into a sterile microcentrifuge tube to act as a negative control. Samples were stored at -80°C before microbiome sequencing targeting the V4 hypervariable region of the 16S rRNA bacterial gene. Statistical analysis was conducted using the PROC GLM procedure in SAS 9.4. A greater relative abundance of the phylum Firmicutes was observed in the preputial diverticulum than the bulbourethral glands, seminal vesicles, and prostate (75.1 ± 3.6% vs. 62.3 ± 3.1%, 59.3 ± 3.1%, 58.4 ± 3.1%, respectively; P < 0.05). Within Firmicutes, the relative abundance of the genus Blautia was reduced in the preputial diverticulum compared with testes, epididymis, seminal vesicles, bulbourethral glands, and prostate (0.6 ± 1.5% vs. 8.1 ± 1.3%, 8.1 ± 1.3%, 8.1 ± 1.3%, 7.6 ± 1.3%, 7.4 ± 1.3%, respectively; P < 0.01). In contrast, the genus Peptoniphilus, under the phylum Firmicutes, was more abundant in the preputial diverticulum than the testes, epididymis, seminal vesicles, bulbourethral glands, and prostate (8.8 ± 1.5% vs. 0.3 ± 1.3%, 0.1 ± 1.3%, 0.2 ± 1.3%, 0.1 ± 1.3%, 0.2 ± 1.3%, respectively; P < 0.01). The relative abundance of the phylum Bacteroidetes within the testes had a decreased relative abundance in comparison to the bulbourethral glands (14.2% vs. 23.6 ± 2.5%; P = 0.01), prostate (14.2% vs. 27.0 ± 2.5%; P = 0.01), and seminal vesicles (14.2% vs. 30.1 ± 2.5%; P = 0.01). The seminal vesicles (6.5% vs. 2.9 ± 0.8%; P < 0.01) and prostate (5.4% vs. 2.9 ± 0.8%; P < 0.05) had a greater relative abundance of the genus Bacteroides, within the phylum Bacteroidetes, than the testes. A greater relative abundance of the phylum Proteobacteria was observed in the preputial diverticulum than the bulbourethral gland, prostate, seminal vesicles, testes, and epididymis (13.5 ± 1.7% vs. 6.3 ± 1.5%, 6.5 ± 1.5%, 5.8 ± 1.5%, 5.6 ± 1.5%, 5.5 ± 1.5%, respectively; P < 0.01). Based on these results, it appears the preputial diverticulum and the testes have distinct bacterial communities that differ from the male accessory sex glands including the prostate, bulbourethral glands, and seminal vesicles. Further research is needed to characterize the boar reproductive tract microbiome and determine its relationship with fertility.

Expression of CSF1, AR, and SRD5A2 during Postnatal Development of the Boar Reproductive Tract.

Simple SummaryUnderstanding the initial development of the male reproductive system, including the prostate, should provide insight into malfunctions in the adult male. Although changes in circulating androgens during development are characterized in multiple species, potential changes in the androgen receptor, in the enzyme that converts testosterone to the presumably more potent dihydrotestosterone, and in colony stimulating factor 1, a critical mediator of macrophage influence on organ development, were previously unknown and anticipated to be influenced by androgens and estrogens. Gene expression in the testis, prostate, and seminal vesicles of these three mediators of development, including responses to reduced testosterone or estrogens, were evaluated. Each of these three genes had a unique temporal pattern of expression during postnatal reproductive tract development. However, surprisingly minimal effects of altered steroid signaling were reported on the expression of these presumed pivotal genes.The male reproductive system develops from a minimally functioning gonad and nonfunctioning accessory sex glands in the neonate; sex steroids, presumed to be primary influencers of these changes, have been characterized in multiple species. This study focused on the expression of the androgen receptor as the principal mediator of androgen-induced signaling; the 5α reductase enzyme that converts testosterone to the more active dihydrotestosterone; and colony stimulating factor 1, a mediator of macrophage influence on organ development in the pig. The time points chosen to evaluate normal developmental changes during the juvenile and prepubertal intervals included the inflection time points of 6.5 weeks of age at the nadir of circulating estradiol and testosterone concentrations in juveniles, and 11 weeks of age, when these concentrations begin to increase. The role of sex steroid signaling in the regulation of gene expression was evaluated by the blockade of androgen and estrogen receptors and reduction in endogenous estrogens. Expression of colony stimulating factor 1 in the testes gradually decreased during development; developmental profiles in the prostate and seminal vesicles were clearly different. Interference with sex steroid signaling had no effect on the expression of these three genes in testicular tissue and minimal and transient effects in prostate and seminal vesicles.

GPx6 is involved in the in vitro induced capacitation and acrosome reaction in porcine sperm

Glutathione peroxidases (GPxs) are regarded as important protectors against oxidative stress. Some members of this protein family were reported to play key roles in protecting sperm against oxidative stress. Whether GPx6 a member of the GPx family also plays a role in protection against oxidative stress is not known to date. The objective of the present study was to evaluate the localization and function of glutathione peroxidase 6 (GPx6) in boar accessory sex glands, seminal plasma, and sperm, as well as the effect of GPx6 on vitality and capacitation in boar sperm. qPCR and Western blot analysis demonstrated the presence of GPx6 in testis, epididymis, bulbourethral glands, prostate, seminal vesicle, sperm and seminal plasma. Incubation of sperm with an GPx6 antibody had no significant effect on the viability of boar sperm prior to capacitation. Surprisingly, when capacitated sperm was incubated with the GPx6 antibody for 240 min, sperm vitality was significantly improved. Western blotting showed that in capacitated sperm without prior pretreatment, GPx6 protein content was reduced compared to sperm before capacitation. To further confirm a role for GPx6 in sperm capacitation, we tested sperm acrosome reaction by ACR.2 and FITC-PSA. The results showed that treatment of sperm with the GPx6 antibody significantly increased sperm capacitation and acrosome reaction. Furthermore, we examined the concentration of cAMP in sperm after capacitation. ELISA demonstrated that the cAMP concentration in the sperm exposed to the GPx6 antibody was significantly higher than that of the control group. In addition, the exposure of sperm to the GPx6 antibody significantly increased the concentration of H2O2, while the expression of SOD3 and CAT were decreased. Based on these observations we would like to postulate that in the boar reproductive tract the GPx6 protein becomes attached to the sperm head preventing the sperm to undergo premature capacitation by affecting components of the antioxidant pathway. How GPx6 expression following ejaculation becomes suppressed to allow sperm capacitation to take place needs further investigation.

The antigenic character of zinc-binding proteins and their localization in boar reproductive tract--a preliminary study.

In this study immunoelectrophoretic and double immunodiffusion analyses were used to investigate the antigenic character of zinc-binding proteins (ZnBPs), whereas the indirect immunofluorescence technique was used to identify their origin in boar reproductive tract. The mmunoelectrophoretic analysis of ZnBPs of the seminal plasma resulted in the appearance of three antigenic protein complexes, while specific immunoreactivity patterns of the anti-ZnBP serum were detected by double immunodiffusion analysis. Indirect immunofluorescence technique confirmed that ZnBPs were secreted by different reproductive tract tissues, suggesting their contributions to the seminal plasma.

Regulation of glucocorticoid metabolism in the boar testis and caput epididymidis by the gonadotrophin-cAMP signalling pathway

In target tissues, cortisol is metabolised by two 11β-hydroxysteroid dehydrogenase (11βHSD) isoenzymes, namely 11βHSD1 and 11βHSD2, both of which are co-expressed in the boar testis and reproductive tract. The present study has assessed whether cortisol-cortisone metabolism in boar testis and caput epididymidis can be regulated via the gonadotrophin-cAMP signalling pathway. 11βHSD activities were measured by using a radiometric conversion assay in static tissue culture. In both testis and caput epididymidis, the net reduction of cortisone but not the net oxidation of cortisol, was significantly decreased by luteinising hormone (by 53 ± 20% and 45 ± 9%, respectively, P < 0.05), forskolin (by 60 ± 7% and 57 ± 9%, respectively, P < 0.01) and 8-bromo-cAMP (by 54 ± 4% and 64 ± 1%, respectively, P < 0.01). This suppression of 11-ketosteroid reductase activity in the boar testis by forskolin could be attenuated by the protein kinase A (PKA) inhibitor, H89. Hence, within the boar testis and the caput epididymidis, the local actions of glucocorticoids are modulated by gonadotrophin-cAMP-PKA signalling via their selective effects on the reductase activity of 11βHSD.

Seasonal changes in antioxidant defence systems in seminal plasma and fluids of the boar reproductive tract

This study aimed to analyze seasonal variations in the antioxidant defence systems of the seminal plasma and fluids of the cauda epididymis and vesicular glands of the boar. The analyzed antioxidants included superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and total L-glutathione (GSH+GSSG). Seasonal changes in total protein content and total antioxidant status (TAS) of the seminal plasma and reproductive fluids were also analyzed. Compared with the spring-summer period, total protein content in the seminal plasma was significantly higher during the autumn-winter period. Among the antioxidants analyzed, only SOD activity showed marked seasonal variations, being significantly higher during the spring-summer period. Likewise, the fluid of the cauda epididymis exhibited greater SOD and CAT activity during the spring-summer period, whereas TAS levels were markedly higher during the autumn-winter period. Neither GPx activity nor total GSH+GSSG content in the cauda epididymal fluid was significantly affected by the seasonal periods. The vesicular gland fluid exhibited an approximately 4-fold greater level of SOD activity during the autumn-winter period, as compared with the spring-summer period. By contrast, greater CAT and GPx activity, and a higher level of total GSH+GSSG were observed in the vesicular gland fluid during the spring-summer period. In conclusion, the findings of this study indicate that seasonal variations could have varying effects on the antioxidant defence systems in the seminal plasma and fluids of the boar reproductive tract.

Antioxidant Defence System of Boar Cauda Epididymidal Spermatozoa and Reproductive Tract Fluids

Antioxidants secreted by the reproductive tract protect spermatozoa against the toxic effects of reactive oxygen species (ROS) after ejaculation. This study aimed at characterizing the level of antioxidant protection in boar cauda epididymidal spermatozoa and fluids of the cauda epididymidis, vesicular and prostate glands. Also, this study investigated the effect of a 5-h period of dialysis on the antioxidant capacity of boar seminal plasma. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GST) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) activities were monitored in the cauda epididymidal spermatozoa or reproductive tract fluids. Also, the concentrations of total glutathione (GSH + GSSG), L-ergothioneine (ERT) and l-ascorbate and the total antioxidant status (TAS) of the fluids were measured. It was found that the cauda epididymidal spermatozoa exhibited high SOD activity and relatively low activity of PHGPx. The relative amounts of GPx, GR and GST activities in the cauda epididymidal spermatozoa were negligible, whereas CAT activity was undetectable. Greater SOD activity was found in the fluids of the cauda epididymidis and prostate gland. Furthermore, the prostate gland fluid appeared to be the main source of CAT activity in the seminal plasma, whereas the highest level of GPx activity was derived from the cauda epididymidal fluid. The reproductive tract fluids exhibited negligible amounts of GR and GST activities. It seemed that the significant amounts of GSH + GSSG, ERT and L-ascorbate in the reproductive tract fluids could have an ameliorative effect on the level of TAS in the seminal plasma. Dialysis had a marked effect on the total antioxidant capacity of the seminal plasma, which was manifested in greater activity of SOD and GPx. The findings of this study confirmed that the scavenging potential of the seminal plasma is dependent on the contributions of different antioxidants, originating in various fluids of boar reproductive tract.

Expression and localization of acrosin inhibitor in boar reproductive tract

Proteinases and proteinase inhibitors play key roles in almost all physiological processes. Proteinase inhibitors are present in all tissues and body fluids. They interfere with the activity of proteinases and thus maintain homeostasis. The main role of proteinase inhibitors in the reproductive tract is the inactivation of prematurely released hydrolytic enzymes from damaged spermatozoa and the protection of reproductive tracts and spermatozoa against proteolytic degradation. In the boar reproductive system, acrosin inhibitors are found in seminal plasma and on spermatozoa. The amino acid sequence of seminal plasma and sperm-associated acrosin inhibitors is 90% identical, and their biochemical properties have been completely resolved. However, their origin and localization have not been fully elucidated. Using rabbit polyclonal antibody, we have studied the expression and localization of the seminal plasma acrosin inhibitor in the boar reproductive tract. The antibody recognizes a 12-kDa band in extracts from the cauda epididymidis, seminal vesicles, prostate, and Cowper's glands, and immunofluorescence has revealed the acrosin inhibitor in the epithelium and lumen of these organs. Gene expression of the acrosin inhibitor has been studied by reverse transcription together with the polymerase chain reaction. Acrosin inhibitor mRNA transcript is detectable in the epididymis, seminal vesicles, prostate, and Cowper's glands. The antibody has localized the acrosin inhibitor on the surface of epididymal and ejaculated spermatozoa in the acrosomal region. In extracts from epididymal and ejaculated spermatozoa, the specific antibody recognizes acrosin inhibitor at 8 kDa and 12 kDa. The presence of acrosin inhibitor on the sperm surface as a protective molecule for receptors mediating the sperm-zona pellucida binding suggests that it is crucial for the reproductive process.

Molecular Cloning and Expression of the CRISP Family of Proteins in the Boar1

The family of mammalian cysteine-rich secretory proteins (CRISP) have been well characterized in the rat, mouse, and human. Here we report the molecular cloning and expression analysis of CRISP1, CRISP2, and CRISP3 in the boar. A partial sequence published in the National Center for Biotechnology Information (NCBI) database was used to derive the full-length sequences for CRISP1 and CRISP2 using rapid amplification of cDNA ends. RT-PCR confirmed the expression of these mRNAs in the boar reproductive tract, and real time RT-PCR showed CRISP1 to be highly expressed throughout the epididymis, with CRISP2 highly expressed in the testis. A search of the porcine genomic sequence in the NCBI database identified a BAC (CH242-199E6) encoding the CRISP1 gene. This BAC is derived from porcine Chromosome 7 and is syntenic with the regions of the mouse, rat, and human genomes encoding the CRISP gene family. This BAC was found to encode a third CRISP protein with a predicted amino acid sequence of high similarity to human CRISP3. Using RT-PCR we show that CRISP3 expression in the boar reproductive tract is confined to the prostate. Recombinant porcine (rp) CRISP2 protein was produced and purified. When incubated with capacitated boar sperm, rpCRISP2 induced an acrosome reaction, consistent with its demonstrated ability to alter the activity of calcium channels.

Expression and Localization of Beta-Microseminoprotein in Boar Reproductive Tract.

Expression and Localization of Beta-Microseminoprotein in Boar Reproductive Tract.

Localization of porcine seminal plasma (PSP) proteins in the boar reproductive tract and spermatozoa

Spermadhesins are proteins containing a characteristic CUB domain, originally isolated from seminal plasma and ejaculated spermatozoa in domestic animals. Boar spermadhesins are multifunctional proteins exhibiting ligand-binding abilities with various endogenous ligands present in the male and female reproductive tracts and may play a role in the reproduction process. Porcine spermadhesins (AQN, AWN, PSP protein families) are secreted mainly by the seminal vesicles, but their mRNAs have been found also in the cauda epididymis and prostate. Unlike AQN and AWN spermadhesins, localization of porcine seminal plasma (PSP) proteins in the boar reproductive tract has not been completely resolved. This work has focused on PSP protein expression and localization in the boar reproductive organs and on spermatozoa. Using specific rabbit polyclonal antibodies (anti-PSP I and anti-PSP II), PSP I and PSP II proteins were immunodetected in tissue extracts and in secretory tissues of cauda epididymis, prostate, seminal vesicles and Cowper's glands on the blots and by an indirect immunofluorescence technique, respectively. Moreover, the ability of PSP proteins to bind to epididymal spermatozoa indicated their presence on cauda epididymal and ejaculated spermatozoa. Porcine seminal plasma proteins bind to the sperm surface at ejaculation and may modulate several aspects of sperm activity during reproduction. PSP proteins are produced not only by seminal vesicles and prostate, but also by epididymis. However, their prospective role in sperm epididymal maturation is not clear. Further characterization of seminal plasma protein forms expressed in the individual reproductive organs will help to understand their subsequent role in the reproduction process.

Localization and characterization of glutathione peroxidase (GPx) in boar accessory sex glands, seminal plasma, and spermatozoa and activity of GPx in boar semen

Boar ejaculate owes its characteristic large volume mainly to accessory sex gland (ASG) secretions. These are main contributors to the protective functions of seminal plasma, especially against oxidative damage. Numerous antioxidants have been detected in ASG secretions, and, respectively, in seminal plasma. However, as regards one key antioxidant protector -- the Se-dependent enzyme glutathione peroxidase (GPx) -- there is no agreement yet among researchers as to its presence in boar seminal plasma. Nevertheless, the beneficial effect of dietary Se supplementation on male fertility has been widely recognized. The aim of the present study was to investigate the localization and characterization of GPx in boar ASGs, seminal plasma, and spermatozoa, as well as to evaluate GPx activity in boar semen. Immunohistochemical assays demonstrated GPx presence in the epithelial cells, vacuole membranes, and vascular endothelium of boar seminal vesicle, prostate and bulbourethral glands. Western blot analysis demonstrated the presence of a monomer form of GPx with MW 20 kDa in lysates from seminal vesicle, prostate, bulbourethral glands, and spermatozoa, but not in seminal plasma. Surprisingly, peroxidase activity detected in seminal plasma from normal ejaculates was nearly three times as high as in spermatozoa. Our findings confirmed the presence of immunoreactive GPx in the boar reproductive tract, while further investigation is still warranted to uncover the exact protein forms involved and their function.

Preliminary characterization of multiple hyaluronidase forms in boar reproductive tract

Hyaluronidases play an important role in gamete interaction and fertility in mammals. The objectives of the present study were to investigate multiple forms of the enzyme in boar reproductive tract using electrophoretic methods. Two forms of hyaluronidase (EC 3.2.1.35) were detected in boar seminal plasma (relative molecular masses of 55,000 and 65,000) using hyaluronic acid-substrate polyacrylamide gel electrophoresis in the presence of SDS. These two forms can be separated by means of affinity chromatography on Heparin-Sepharose. They differ, besides their affinity to heparin, also in the pH optimum of their enzymatic activity. The form with relative molecular mass of 55,000 was active both at the acidic (pH 3.7) and the neutral pH (pH 7.4) and was bound to immobilized heparin. The second form (relative molecular mass 65,000) was active only at acidic pH and did not interact with heparin. The same acidic-active form (65,000) was found in seminal vesicle fluids. The hyaluronidase form which is active both at the acidic and the neutral pH (51,000) was detected in epididymal fluid. In the detergent extracts of boar sperm, three active forms of the enzyme were found (relative molecular masses 55,000, 70,000 and 80,000). The form of relative molecular mass 55,000 was active in a wide range of pH (pH 3–8). The forms of relative molecular masses 70,000 and 80,000 were active only at neutral pH.

CHARACTERIZATION OF CRISP PROTEIN FAMILY IN THE BOAR

The family of androgen-dependent, cysteine-rich secretory proteins (Crisp) are characterized by sixteen conserved cysteine residues in their amino acid sequence. Crisp 1 has been shown to inhibit capacitation in rat sperm. This function may be of extreme importance to the swine industry in terms of suppression of capacitation in cryopreserved boar sperm. With the functional importance of these proteins in mind, we characterized the Crisp proteins (Crisp 1, 2, and 3) in the boar. Beginning with partial cDNA sequence published in the NCBI database, rapid amplification of cDNA ends was used to derive the full length mRNA sequences for Crisp 1 and 2. RT PCR and real time PCR confirmed the expression of these mRNAs in the boar reproductive tract with Crisp 1 highly expressed throughout the epididymis and Crisp 2 highly expressed specifically in the testis. Using an antibody against rat Crisp 1, Crisp 1 protein was demonstrated by western blot in epididymal fluid. Screening of the porcine genomic sequence in the NCBI database produced a BAC encoding the Crisp 1 gene. This BAC is derived from porcine chromosome 7 and is syntenic with the regions of the mouse, rat, and human genomes encoding the Crisp gene family. This BAC appears to encode porcine Crisp 3 and expression of this mRNA is currently being characterized. Production of recombinant Crisp 1 and 2 proteins is ongoing to allow for further functional characterization of these proteins with boar sperm. In conclusion, we have characterized the Crisp family of proteins in the boar reproductive tract. (poster)

Measurement of immunoglobulin G, A and M concentrations in boar seminal plasma

How the immune system relates to the boar reproductive tract is not well defined. This is an important area of study because disease-causing agents may be transmitted through boar semen. We have previously identified porcine reproductive and respiratory syndrome virus (PRRSV) in boar semen and wanted to identify PRRSV-specific antibodies within seminal plasma. However, literature documenting total immunoglobulin concentration or the predominant immunoglobulin isotype in boar semen was not available. Therefore, we developed a sandwich enzyme-linked immunoassay (ELISA) to quantitate total IgG, IgA and IgM in seminal plasma from 16 healthy, nonvaccinated, adult boars (n= 102 semen samples). In seminal plasma, IgG was the predominant isotype followed by IgA and IgM. Mean levels ± the standard deviation followed by the 95% confidence interval of IgG, IgA and IgM were 23.2 ± 14 μg/mL (15.5 to 31.0), 4.8 ± 2.5 μg/mL (3.5 to 6.2) and 3.7 ± 1.7 μg/mL (2.7 to 4.7), respectively. These concentrations of immunoglobulins in seminal plasma were considerably lower than in other swine secretions, which might allow for the survival of infectious agents in boar semen.