High total antioxidant capacity of the porcine seminal plasma (SP-TAC) relates to sperm survival and fertility

The study attempted to clarify the role of total antioxidant capacity of seminal plasma (SP-TAC) on boar sperm survival and fertility after artificial insemination (AI). SP-TAC differed (P < 0.001) among boars (n° = 15) and, to a lesser degree, among ejaculates within male (4 ejaculates/boar). SP-TAC also differed (P < 0.001) among ejaculate fractions (43 ejaculates and 3 fractions per ejaculate), of which the sperm-peak portion of the sperm rich ejaculate fraction (SRF) had the highest SP-TAC. SP-TAC was not correlated with sperm quality (motility and viability) or functionality (intracellular ROS generation and lipid peroxidation) of liquid AI-semen samples stored at 17 °C for 72 h (90 AI-samples), but the decline in sperm quality was larger (P < 0.05) in ejaculates with low, compared with high SP-TAC (hierarchically grouped). The SP-TAC differences among ejaculate portions agree with sperm cryosurvival rates (14 ejaculates from 7 boars), showing sperm from sperm-peak portion better (P < 0.01) post-thaw quality and functionality than those from the entire ejaculate (mainly post-SRF). Boars (n° = 18) with high SP-TAC (hierarchically grouped) had higher (P < 0.05) fertility outcomes (5,546 AI-sows) than those with low SP-TAC. Measurement of SP-TAC ought to be a discriminative tool to prognosis fertility in breeding boars.

The Seminal Plasma of the Boar is Rich in Cytokines, with Significant Individual and Intra-Ejaculate Variation

PROBLEM

The boar, as human, sequentially ejaculates sperm-rich and sperm-poor fractions. Seminal plasma (SP) spermadhesins (PSP-I/PSP-II) induce a primary endometrial inflammatory response in female sows, similar to that elicited by semen deposition in other species, including human. However, the SP is also known to mitigate such response, making it transient to allow for embryo entry to a cleansed endometrium. Although cytokine involvement has been claimed, the exploration of cytokines in different SP fractions is scarce. This study determines Th1, Th2, Th17 and Th3 cytokine profiles in specific ejaculate SP fractions from boars of proven fertility.

METHODS

SP samples from the sperm-rich fraction (SRF) and the sperm-poor post-SRF fraction (post-SRF) of manually collected ejaculates from eight boars (four ejaculates per boar) were analysed by commercial multiplex bead assay kits (Milliplex MAP, Millipore, USA) for interferon-γ, interferon gamma-induced protein 10, macrophage-derived chemokine, growth-regulated oncogene, granulocyte-macrophage colony-stimulating factor, monocyte chemo-attractant protein-1, interleukins (IL)-6, IL-8, IL-10, IL-15, IL-17 and transforming growth factor (TGF)-β1-β3.

RESULTS

Cytokine concentrations differed between the ejaculate fractions among boars, being highest in the post-SRF.

CONCLUSION

Boar SP is rich in Th1, Th2, Th17 and Th3 cytokines, with lowest concentrations in the sperm-peak-containing fraction, indicating its main immune influence might reside in the larger, protein-rich sperm-poor post-SRF.

The activity of paraoxonase type 1 (PON-1) in boar seminal plasma and its relationship with sperm quality, functionality, and in vivo fertility

Paraoxonase 1 (PON-1) is a hydrolytic enzyme present in body fluids, capable of protecting cells against oxidative stress. The hypothesis was hereby to test that PON-1, present in seminal plasma (SP), acts protecting boar spermatozoa when showing a reasonable high activity in the ejaculate. SP-PON-1 activity differed (p < 0.001) among boars (from 0.10 to 0.29 IU/mL). Intra-boar variability was also observed (p < 0.05), but only in two of the 15 boars. SP-PON-1 activity differed among ejaculate portions, showing the spermatozoa-peak portion of spermatozoa-rich ejaculate fraction the highest levels (0.35 ± 0.03 IU/mL, ranging from 0.12 to 0.69) and the post-sperm ejaculate fraction the lowest levels (0.12 ± 0.01 IU/mL, ranging from 0.03 to 0.21). SP-PON-1 activity was positively correlated with the percentage of spermatozoa with rapid and progressive movement (p < 0.01) and negatively correlated with the generation of intracellular reactive oxygen species (p < 0.01) in semen samples after 72 h of liquid storage. SP-PON-1 activity was highest (p < 0.01) in boars with highest farrowing rates. In conclusion, SP-PON-1 activity differed among boars and ejaculate fractions/portions. SP-PON-1 activity was positively correlated with sperm quality and functionality of liquid-stored semen samples and it evidenced a positive association with in vivo fertility.

Measurement of activity and concentration of paraoxonase 1 (PON-1) in seminal plasma and identification of PON-2 in the sperm of boar ejaculates

This study revealed and characterised the presence of the antioxidant enzymes paraoxonase (PON) type 1 (PON-1, extracellular) and type 2 (PON-2, intracellular) in boar semen. To evaluate PON-1, an entire ejaculate from each of ten boars was collected and the seminal plasma was harvested after double centrifugation (1,500g for 10 min). Seminal plasma was analysed for concentration as well as enzymatic activity of PON-1 and total cholesterol levels. Seminal-plasma PON-1 concentration ranged from 0.961 to 1.670 ng/ml while its enzymatic activity ranged from 0.056 to 0.400 IU/ml, which represent individual variance. Seminal-plasma PON-1 concentration and enzymatic activity were negatively correlated (r = -0.763; P < 0.01). The activity of seminal-plasma PON-1 negatively correlated with ejaculate volume (r = -0.726, P < 0.05), but positively correlated with sperm concentration (r = 0.654, P < 0.05). Total seminal-plasma cholesterol concentration positively correlated with PON-1 activity (r = 0.773; P < 0.01), but negatively correlated with PON-1 concentration (r = -0.709; P < 0.05). The presence of intracellular PON-2 was determined via immunocytochemistry in spermatozoa derived from artificial insemination. PON-2 localised to the post-acrosomal area of the sperm head and principal piece of the tail in membrane-intact spermatozoa. In summary, PON is present in boar semen, with PON-1 at low levels in seminal plasma and PON-2 within the spermatozoa. Further studies are needed to characterise the relationship between antioxidant PONs with sperm and other seminal-plasma parameters.

Boar sperm cryosurvival is better after exposure to seminal plasma from selected fractions than to those from entire ejaculate

Boar bulk ejaculates are now being collected instead of usual sperm-rich fractions (SRF) for artificial insemination purpose. The present study evaluated the influence of holding boar sperm samples before freezing surrounded in their own seminal plasma (SP), from either fractions/portions or the entire ejaculate, on post-thawing sperm quality and functionality. Ejaculates collected as bulk (BE) or as separate (first 10 mL of SRF [P1] and rest of SRF [P2]) from 10 boars were held 24h at 15-17°C and then frozen. Some bulk ejaculate samples were frozen immediately after collections as Control. In addition, epididymal sperm samples from the same 10 boars were collected post-mortem and extended in SP from P1 (EP1), P2 (EP2) and post SRF (EP3), and also held 24h before freezing for a better understanding of the influence of SP on boar sperm cryopreservation. The sperm quality (motility, evaluated by CASA, and viability, evaluated by flow cytometry) and functionality (flow cytometry assessment of plasma membrane fluidity, mitochondrial membrane potential and intracellular generation of reactive oxygen species [ROS] in viable sperm) were evaluated at 30, 150 and 300 min post-thaw. Post-thawing sperm quality and functionality of P1 and P2 were similar but higher (p < 0.01) than BE samples. Control samples showed higher (p < 0.01) post-thaw sperm quality and functionality than BE samples. Post-thawing sperm quality and functionality of EP1 and EP2 were similar but higher (p < 0.05) than EP3. These results showed that boar sperm from BE are more cryosensitive than those from the SRF, particularly when held 24h before freezing, which would be attributable to the cryonegative effects exerted by the SP from post SRF.

Verrucous hemangioma with pseudoepitheliomatous epidermal hyperplasia in an adult horse

Verrucous hemangiomas are a rare specific variant of equine skin tumors not well described in the literature. An 8-year-old gelding presented a unilateral lesion on the pastern. Macroscopically, the mass showed a warty and verrucous surface with focal ulcerations. The histology showed a dermal proliferation of endothelial-layered capillaries and venules separated by a delicate stroma of scant fibroblasts and collagen deposition, with pseudoepitheliomatous hyperplasia (exuberant reactive irregular epithelial hyperplasia with tongue-like projections extending into the dermis, mimicking downgrowth of squamous cell carcinoma) and orthokeratotic hyperkeratosis of the overlying epidermis. The immunohistochemical study confirmed the endothelial origin of the tumor, and a final diagnosis of verrucous hemangioma with pseudoepitheliomatous hyperplasia was confirmed. To the knowledge of the authors, this is the first detailed description of this entity in adult horses. Moreover, the clinical progression and epidermal changes have not been previously reported, emphasizing the importance of a pathological study of any epithelial preneoplastic lesion to rule out an underlying dermal neoplasia.

Suitability and effectiveness of single layer centrifugation using Androcoll-P in the cryopreservation protocol for boar spermatozoa

The goal of the present experiment was to evaluate the suitability and effectiveness of single layer centrifugation (SLC), using the pig-specific colloid Androcoll-P, as a routine procedure for selecting boar spermatozoa for cryopreservation. The study focuses special attention on the effectiveness of SLC for processing a whole sperm rich ejaculate fraction and the fertilizing ability of frozen-thawed (FT) sperm selected using SLC prior to freezing. Thirteen sperm rich ejaculate fractions (one per boar) were split into three aliquots. Two aliquots of 15 and 150mL were SLC-processed (500×g for 20min) using 15 and 150mL (v/v) of Androcoll-P-Large and Androcoll-P-XL, respectively. The third aliquot remained un-processed as a control. The percentages of spermatozoa that were morphologically normal and showed rapid and progressive motility (assessed by CASA) spermatozoa were higher (P<0.01) and those with fragmented nuclear DNA (sperm chromatin dispersion test) were lower (P<0.01) after SLC than control semen samples, regardless of the Androcoll-P used. The recovery rates of total, motile, viable (flow cytometric evaluated after staining with H-42, PI and FITC-PNA) and morphologically normal spermatozoa ranged between 20 and 100% and those with intact nuclear DNA ranged between 60 and 100%, irrespective of the Androcoll-P used. Thereafter, the semen samples were cryopreserved using a standard 0.5-mL straw freezing protocol. Post-thaw percentages of sperm motility (both total motility and rapid progressive motility), viability and intact nuclear DNA were higher (P<0.05) in SLC-processed than in control semen samples, irrespective of the Androcoll-P used. SLC-processing also improved the in vitro fertilizing ability of FT-sperm (679 in vitro matured oocytes inseminated with a viable sperm:oocyte ratio of 300:1 and coincubated for 6h), measured as the percentage of penetrated oocytes and the mean number of swollen sperm heads and/or male pronuclei in penetrated oocytes. However, there was no effect of SLC-processing on the in vitro ability of putative zygotes to develop to blastocysts. Overall these results indicate that SLC-processing of boar ejaculates using Androcoll-P improves the quality and fertilizing ability of cryosurvival boar sperm. However, efforts should be made to ensure continued high recovery yields before considering the inclusion of SLC as a routine procedure in the cryopreservation protocol of boar ejaculates.

Downregulation of antigen-presenting cells in tonsil and lymph nodes of porcine reproductive and respiratory syndrome virus-infected pigs

Porcine reproductive and respiratory syndrome virus (PRRSV) can persist in different organs of infected pigs, which suggests a failure in the immune response. Antigen-presenting cells (APCs) play a pivotal role in the induction of effective T- and B-cell responses. In this study, we investigated the changes in the different APC subpopulations and T- and B-cell counts in the tonsil, retropharyngeal and mediastinal lymph nodes of pigs experimentally infected with a European PRRSV field isolate. Our results demonstrated that the expression of S100, SWC3, HLA-DR molecule and CD3 was diminished in the studied organs throughout the study, observing a significant negative correlation between viral antigen and HLA-DR expression in both retropharyngeal and mediastinal lymph nodes. In contrast, λ-light chains showed an increase during the study. Taking all into account, after PRRSV infection, no enhancement in the number of APCs and T cells was observed, suggesting an impairment of the immune function which may allow the persistence of PRRSV into the organism.

Type 2 Porcine Reproductive and Respiratory Syndrome Virus infection mediated apoptosis in B- and T-cell areas in lymphoid organs of experimentally infected pigs

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) infection is characterized by persisting in lungs and lymphoid tissue, resulting in systemic lymphoid depletion. The aim of this study was to correlate the histological changes, viral antigen expression and apoptosis phenomena in tonsil, medial retropharyngeal and mediastinal lymph nodes of 12 pigs inoculated with a type 2 PRRSV isolate (Chilean strain 2402). Apoptosis phenomena were observed mainly in lymphocytes and secondly in macrophages of lymph nodes and tonsils of inoculated animals, showing a peak of both apoptotic cells and viral antigen expression at the end of the study (21 dpi). However, the number of apoptotic cells was higher than the number of PRRSV-positive cells at the end of the study. This finding together with the location of apoptotic cells and PRRSV-positive cells in different structures of lymphoid organs supports the hypothesis that PRRSV-positive macrophages might modulate the apoptosis phenomena in other cells, mainly lymphocytes, by means of an indirect mechanism. Furthermore, apoptotic cells were detected both in B- and T-cell areas of lymphoid organs, suggesting that apoptosis phenomena may play a role in the impairment of the host immune response during PRRS.

Malignant mesenchymoma of the heart base in a dog with infiltration of the pericardium and metastasis to the lung

A 9-year-old male rottweiler was presented with abdominal distension, ascites and respiratory distress and marked bulging in the perineal region. At necropsy examination the animal had profuse ascites and hydropericardium and a multinodular mass in the right auricle of the heart infiltrating the epicardium and pericardium and metastasizing to the caudal lobe of the left lung. Microscopically and immunohistochemically the tumour was composed of neoplastic cells with muscular, cartilaginous and adipose differentiation. A diagnosis of malignant mesenchymoma with leiomyosarcomatous (≈ 50%), rhabdomyosarcomatous (≈ 30%), chondrosarcomatous (25%) and liposarcomatous (5%) components was made. Metastatic malignant mesenchymoma has not been reported previously at this site in the dog.

Differential expression of proinflammatory cytokines in the lymphoid organs of porcine reproductive and respiratory syndrome virus-infected pigs

Porcine reproductive and respiratory syndrome (PRRS) is considered one of the most important diseases in the swine industry. Although several studies have been carried out to elucidate the host immune response evoked against PRRS virus (PRRSV), there are several aspects that still remain unclear. The aim of this study was to determine the expression of IL-1α, IL-6 and TNF-α in the lymphoid organs (mediastinal and retropharyngeal lymph nodes and tonsil) of PRRSV-infected pigs and to determine their correlation with the expression of PRRSV antigen. Proinflammatory cytokine expression was different depending on the body compartment examined. Thus, whereas IL-1α and TNF-α were the main cytokines expressed in the mediastinal lymph node, IL-6 was the most highly expressed cytokine in the retropharyngeal lymph node, and no expression of proinflammatory cytokines was observed in the tonsil. These findings may be related to the impairment of the host immune response evoked after PRRSV infection. Therefore, lymphoid organs and proinflammatory cytokines represent an important target of study for clarifying the immunopathogenesis of PRRS.

Acute phase response in porcine reproductive and respiratory syndrome virus infection

This study was focused on the changes observed in the serum concentration of haptoglobin (Hp), C-reactive protein (CRP), serum amyloid A (SAA) and Pig-major acute protein (Pig-MAP), during experimental porcine reproductive and respiratory syndrome virus (PRRSV) infection and in their relationship with the expression of interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). Hp and Pig-MAP serum levels were increased at 10 dpi, but CRP and SAA showed a delayed and highly variable increase. All three proinflammatory cytokines were poorly expressed, and only a mild increase in IL-1β was observed at 7 dpi. The increased expression of Hp coincided with the light enhancement observed in both IL-6 and TNF-α, and might be related with an increased expression of IL-10. The low expression of TNF-α might point to a possible mechanism of viral evasion of host-immune response. This issue and the delayed expression of CRP and SAA should be taken into account in future studies about modulation of the immune response by PRRSV infection.