Equine seminal plasma and sperm membrane: Functional proteomic assessment.

During ejaculation, a large amount of seminal plasma proteins interact with the sperm membrane, leading to a series of biochemical and structural changes implicated in sperm function and gamete interaction. However, the roles of the majority of these proteins remain unknown. This study aimed to investigate the proteome and functionality of the major equine proteins of seminal plasma and the sperm membrane. Seminal plasma and enriched-membrane proteins (150 µg) were separated by two-dimensional gel electrophoresis, and the respective maps were analyzed. Protein identification was performed by in-gel digestion and tandem mass spectrometry (GeLC-MS/MS). Samples were also submitted to in-solution digestion (complex protein mixture) and identified by shotgun analysis by LC-MS/MS; bioinformatic tools were used to investigate protein functions. Seminal plasma and sperm membrane extract maps contained 91.0 ± 8.2 spots and 245.3 ± 11.3 spots, respectively, within the 3-10 pH range. In total, the most abundant proteins identified in 2D maps and in complex protein mixtures included 24 proteins for seminal plasma and 33 for sperm membrane extract, with a high degree of confidence (P < 0.05). Of these, HSP1, CRISP3 and KLK1E2 were the most abundant in seminal plasma; HSP1 was highly abundant in sperm membrane extract, in many isoforms, which is related to membrane destabilization and may compromise sperm preservation. HSP1-polybromo-1 interactions suggested a role in DNA stabilization. Prosaposin was identified in seminal plasma and may play a role in the fertilization process. IZUMO4, a member of the IgSF family involved in the prefertilization stages, was identified in 2D gel and MS/MS analysis of sperm membrane extract. Ten proteins of seminal plasma were found to interact with the sperm membrane and were related to binding and catalytic activities (clusterin, CRISP3, epididymal sperm-binding protein 1, kallikrein1E2, seminal plasma protein A3, and HSP1). Additionally, other identified proteins were associated with DNA integrity, capacitation and recognition of pregnancy. These findings indicate that the binding of specific proteins to the plasma membrane during ejaculation may influence sperm survival after cryopreservation and may play a role in decreasing the quality in stallions with toxic seminal plasma. Elucidation of these interactions is an important step in understanding the biological processes related to equine fertility and facilitates future investigations on the selection and application of low freezability semen strategies.

The influence of insemination dose on pregnancy per fixed-time artificial insemination in beef cows is affected by semen extender

The aim of this study was to compare the efficacy of two extenders (Tris-egg yolk - TRIS and Botu-Bov® - BB, Botupharma, Brazil) for bovine semen cryopreservation with a different number of sperm per straw (6, 12, 25 or 50 x 106 sperm per straw) on post-thaw seminal viability (experiment 1) and pregnancy per artificial insemination (P/AI; experiment 2). In experiment 1, higher values of linearity and straightness associated to low amplitude of lateral head displacement (ALH) were observed in samples cryopreserved with BB extender, when compared to samples cryopreserved with TRIS extender (P < 0.05) regardless of the sperm concentration per straw. The pregnancy rates were 57.63, 60.32, 59.26 and 62.50% respectively for 6, 12, 25 or 50 x 106 sperm/straw in BB samples and 45.61, 48.84, 60.34 and 70.59% respectively for the TRIS extender. Increasing the number of sperm had a significant effect on P/AI (P < 0.05) when TRIS extender was used. In conclusion, Botu-Bov® extender promotes better post-thaw sperm movement. The increase in the number of sperm cells per insemination dose improved P/AI rates in Bos indicus lactating beef cows inseminated when using Tris-egg yolk extender.

The influence of insemination dose on pregnancy per fixed-time artificial insemination in beef cows is affected by semen extender

The aim of this study was to compare the efficacy of two extenders (Tris-egg yolk - TRIS and Botu-Bov® - BB, Botupharma, Brazil) for bovine semen cryopreservation with a different number of sperm per straw (6, 12, 25 or 50 x 106 sperm per straw) on post-thaw seminal viability (experiment 1) and pregnancy per artificial insemination (P/AI; experiment 2). In experiment 1, higher values of linearity and straightness associated to low amplitude of lateral head displacement (ALH) were observed in samples cryopreserved with BB extender, when compared to samples cryopreserved with TRIS extender (P < 0.05) regardless of the sperm concentration per straw. The pregnancy rates were 57.63, 60.32, 59.26 and 62.50% respectively for 6, 12, 25 or 50 x 106 sperm/straw in BB samples and 45.61, 48.84, 60.34 and 70.59% respectively for the TRIS extender. Increasing the number of sperm had a significant effect on P/AI (P < 0.05) when TRIS extender was used. In conclusion, Botu-Bov® extender promotes better post-thaw sperm movement. The increase in the number of sperm cells per insemination dose improved P/AI rates in Bos indicus lactating beef cows inseminated when using Tris-egg yolk extender.(AU)

Cooling of ejaculated and epididymal stallion sperm / Refrigeração de espermatozoides do ejaculado e epidídimo em garanhões

After a serious injury or sudden death, epididymis cauda sperm recovery and cryopreservation may present as the last opportunity to obtain genetic material from a valuable stallion. This study evaluated the viability of cooled equine sperm collected by three different methods: sperm of ejaculated (G1), sperm recovered from the epididymal cauda immediately after orchiectomy (G2) and sperm recovered from the epididymal cauda after storage for 24 hours at 5°C (G3). To obtain G1 sperm, two ejaculates were collected. After 1 week, all stallions underwent a bilateral orchiectomy, and one of the removed epididymides was flushed to obtain G2 sperm. The contralateral epididymis was stored at 5°C for 24 hours before being flushed to obtain G3 sperm. The sperm samples were evaluated immediately after the addition of the refrigeration extender, and after 24 and 48 hours of storage at 5°C. After 24 and 48 hours of storage, the epididymal sperm demonstrated higher motility traits when compared to the ejaculated sperm (P<0.05). These results indicate that sperm recovered from the epididymal cauda of stallions are more resistant to the cooling process, with higher kinetic parameters and plasma membrane integrity when compared to the ejaculated sperm.

A recuperação de espermatozoides da cauda do epidídimo pode ser a última chance para preservação do germoplasma quando ocorre morte súbita ou lesão grave em garanhões de alto valor genético. O presente trabalho comparou a viabilidade após refrigeração dos espermatozoides do ejaculado (G1), recuperados da cauda do epidídimo imediatamente após a orquiectomia (G2) e recuperados após armazenamento do epidídimo por 24 horas a 5ºC (G3). No G1 foram colhidos dois ejaculados. Uma semana após a colheita dos ejaculados os garanhões foram submetidos à orquiectomia bilateral e realizada a colheita dos espermatozoides da cauda do epidídimo de um testículo de cada garanhão (G2). O testículo contralateral permaneceu a 5°C por 24 horas, antes da recuperação espermática (G3). A análise das amostras foi realizada imediatamente após a adição do meio de refrigeração, e após 24 e 48 horas de armazenamento a 5°C. Após 24 e 48 horas de armazenamento, os espermatozoides do epidídimo demonstraram características de cinética maiores que os do ejaculado (P<0.05). Estes resultados indicam que espermatozoides recuperados da cauda do epidídimo foram mais resistentes ao processo de refrigeração, com maiores parâmetros de cinética espermática e integridade da membrana plasmática quando comparados aos espermatozoides do ejaculado.

Cooling of ejaculated and epididymal stallion sperm / Refrigeração de espermatozoides do ejaculado e epidídimo em garanhões

After a serious injury or sudden death, epididymis cauda sperm recovery and cryopreservation may present as the last opportunity to obtain genetic material from a valuable stallion. This study evaluated the viability of cooled equine sperm collected by three different methods: sperm of ejaculated (G1), sperm recovered from the epididymal cauda immediately after orchiectomy (G2) and sperm recovered from the epididymal cauda after storage for 24 hours at 5°C (G3). To obtain G1 sperm, two ejaculates were collected. After 1 week, all stallions underwent a bilateral orchiectomy, and one of the removed epididymides was flushed to obtain G2 sperm. The contralateral epididymis was stored at 5°C for 24 hours before being flushed to obtain G3 sperm. The sperm samples were evaluated immediately after the addition of the refrigeration extender, and after 24 and 48 hours of storage at 5°C. After 24 and 48 hours of storage, the epididymal sperm demonstrated higher motility traits when compared to the ejaculated sperm (P<0.05). These results indicate that sperm recovered from the epididymal cauda of stallions are more resistant to the cooling process, with higher kinetic parameters and plasma membrane integrity when compared to the ejaculated sperm.(AU)

A recuperação de espermatozoides da cauda do epidídimo pode ser a última chance para preservação do germoplasma quando ocorre morte súbita ou lesão grave em garanhões de alto valor genético. O presente trabalho comparou a viabilidade após refrigeração dos espermatozoides do ejaculado (G1), recuperados da cauda do epidídimo imediatamente após a orquiectomia (G2) e recuperados após armazenamento do epidídimo por 24 horas a 5ºC (G3). No G1 foram colhidos dois ejaculados. Uma semana após a colheita dos ejaculados os garanhões foram submetidos à orquiectomia bilateral e realizada a colheita dos espermatozoides da cauda do epidídimo de um testículo de cada garanhão (G2). O testículo contralateral permaneceu a 5°C por 24 horas, antes da recuperação espermática (G3). A análise das amostras foi realizada imediatamente após a adição do meio de refrigeração, e após 24 e 48 horas de armazenamento a 5°C. Após 24 e 48 horas de armazenamento, os espermatozoides do epidídimo demonstraram características de cinética maiores que os do ejaculado (P<0.05). Estes resultados indicam que espermatozoides recuperados da cauda do epidídimo foram mais resistentes ao processo de refrigeração, com maiores parâmetros de cinética espermática e integridade da membrana plasmática quando comparados aos espermatozoides do ejaculado.(AU)

Cryopreservation and fertility of ejaculated and epididymal stallion sperm.

The cryopreservation of epididymal sperm is important to preserve genetic material from valuable deceased males. This study evaluated the viability of sperm samples from eight stallions under three conditions: (1) collected using an artificial vagina (EJ-0h), (2) recovered from the epididymal cauda immediately after orchiectomy (EP-0h), and (3) recovered from the epididymal cauda after 24h of storage at 5°C (EP-24h). To obtain EJ-0h sperm, two ejaculates were collected from each stallion. After 1 week, the stallions were submitted to bilateral orchiectomy, and one of the removed epididymides was flushed to obtain EP-0h sperm. The contralateral epididymis was stored at 5°C for 24h before being flushed to obtain EP-24h sperm. The sperm samples were analyzed at three different times: immediately after sperm recovery, after dilution in the freezing extender, and post-thawing. A fertility trial was performed using 39 estrous cycles. After ovulation induction with 1mg of deslorelin acetate (i.m.), mares were inseminated with 800×10(6) sperm. The total number of sperm recovered was 7.8±4.7×10(9) for EJ-0h sperm, 12.9±9.2×10(9) for EP-0h sperm and 12.0±8.0×10(9) for EP-24h sperm. The sperm motility, evaluated by total motility, progressive motility and the percentage of rapid cells, was similar among the samples before and after freezing (P>0.05). However, the plasma membrane integrity was different between EJ-0h and EP-0h pre-freezing and between EJ-0h and EP-24h post-thawing (P<0.05). The conception rates were similar between groups inseminated with sperm recovered from the epididymal cauda immediately after orchiectomy (EP-0h), after 24h of storage at 5°C of the epididymal cauda (EP-24h) and with ejaculated sperm (EJ-0h) (P>0.05). In conclusion, the viability and fertility of cauda epididymal sperm are similar to those of ejaculated sperm.