Membrane status and in vitro capacitation of porcine sperm preserved in long-term extender at 16 degrees C

In vitro exposure of porcine spermatozoa to methylparaben, and propylparaben, alone or in combination adversely affects sperm quality

Parabens (PBs) are widely used in the cosmetic, pharmaceutical, and food industries as preservatives of products. Because of its great use, humans and other organisms are highly exposed daily. However, little is known about the effect of PBs on male infertility. Therefore, the aim of the present study was to evaluate the effect of methylparaben (MePB) and propylparaben (PrPB), alone or in combination, on the physiological characteristics of pig in vitro exposed sperm to different concentrations (0, 200, 500, and 700 μM) for viability, motility, and acrosome integrity evaluation and (0, 200, 500, 700, 1000, and 2000 μM) for DNA fragmentation index evaluation, after 4 h of exposure. The results showed that sperm viability decreased after exposure to MePB from the concentration of 500 μM. In the PrPB and mixture groups, viability decreased at all concentrations except for the control. The decrease in viability of sperm exposed to PrPB was greater than that of the mixture and MePB groups. Sperm motility decreased in all the experimental groups exposed to PBs, at all concentrations, except for the control group. Acrosome integrity was not decreased in the MePB group; however, in the PrPB group, it decreased at a concentration of 200 μM and in the mixture at 500 μM. All groups exhibited DNA damage at different concentrations, except for the control group. Additionally, the effect of PBs on sperm quality was concentration-dependent. The results demonstrated that MePB and PrPB alone or in combination can have adverse effects on sperm quality parameters. MePB had lower toxicity than did both PrPB and the mixture. The mixture did not have an additive effect on any of the parameters evaluated. This could partially explain the link between PB exposure and infertility.

Changes in the Morphology and Antioxidant Status of European Red Deer Sperm Stored in the Epididymides and in a Liquid State

The aim of this study was to evaluate the motility, morphology, and antioxidant status of European red deer sperm stored in a liquid state (variant I) and in the epididymides (variant II). Spermatozoa were harvested post-mortem from the cauda epididymis. Sperm samples in both variants were stored for up to six days (D6) at 5 °C. Spermatozoa were assessed for motility, viability, morphology, activity of antioxidant enzymes (superoxide dismutase, SOD; glutathione peroxidase, GPx; catalase, CAT), and lipid peroxidation (malondialdehyde, MDA, content). Sperm samples were analyzed on storage days 0, 2, 4, and 6 (D0-D6). Storage time and storage method significantly (p ≤ 0.05) influenced the examined variables. On D2, a decrease in motility and acrosomal integrity was observed in both storage variants, whereas a decrease in viability and an increase in MDA content were noted in spermatozoa stored in the epididymides. On D4, higher values of SOD and GPx activity and MDA content were noted in variant I than in variant II. Catalase activity was very low. GPx is the key enzyme that participates in the reduction of hydrogen peroxide in sperm cells. Spermatozoa stored in a liquid state were characterized by higher motility and viability, improved morphology and antioxidant status than those stored in the epididymides; therefore, liquid storage is more recommended for short-term preservation of epididymal spermatozoa.

Analysis of changes in the morphological structures of sperm during preservation of liquid boar semen in two different seasons of the year

Animal fertility is the result of a combination of genetic, physiological and environmental factors. Assessment of semen quality plays a key role in determining the reproductive performance of boars. The aim of the study was to determine the effect of two seasons of the year on the morphology, morphometry, cell membrane integrity and mitochondrial activity of sperm during storage of liquid boar semen at 17 °C. The study was carried out using 20 boars. Four ejaculates were collected from each boar in each of two seasons of the year. All tests were carried out five times: at 1, 24, 48, 96 and 168 h during storage. The results showed that sperm in ejaculates collected in summer are more sensitive to storage conditions than those from ejaculates obtained in winter. The percentage of sperm with morphological defects was shown to increase with the storage time of the diluted ejaculates, particularly between 96 and 168 h of preservation. In summer, the percentage of sperm with an intact cell membrane and the percentage with high mitochondrial membrane potential are much lower than in winter, at every hour of semen preservation. In the case of boars used for artificial insemination, it is worth taking into account the season when the semen is collected, especially if it is to be stored in liquid form. Assessment of sperm cell structures during storage of liquid semen should be implemented at insemination stations and should be carried out more often in summer.

Toxicity and antimicrobial effect of silver nanoparticles in swine sperms

Bacterial contamination in swine semen affects the quality and longevity of sperm and consequently fertility is reduced. Antibiotics have been used to prevent bacterial growth, but the frequency of bacterial resistance to various antibiotics are increasing. Silver nanoparticles (AgNPs) of 10-20 nm in size have shown a biocide effect in bacteria and fungi microorganisms without toxicity to certain mammalian cells. The goal of this study was to analyze both, antimicrobial activity against Staphylococcus aureus and toxicity in swine sperms after 10-20 nm AgNPs treatment. S. aureus proliferation decreased when concentrations from 0.4 to 10 mM AgNPs were assayed. Also, sperm viability measured by mitochondrial metabolism after AgNPs treatment up to a concentration of 10 mM, was viable. In addition, viability determined by membrane integrity of sperms showed that AgNPs treatment up to a concentration of 10 mM was safe. Sperm morphology was evaluated by automated quantification of proximal and distal drops and whiptails. Data indicated that AgNPs treatment up to a concentration of 4 mM were harmless. Finally, sperm capacitation and acrosome reactions were determined by (chlortetracycline) CTC assay. Data showed that no changes in sperm capacitation were observed when sperms were treated with 2 mM of AgNPs, but data showed increased calcium mobilization when treated with 10 mM AgNPs, which suggested sperm capacitation. Finally, there were no significant changes encountered on sperm acrosome reaction for any of the treatments after AgNPs treatment. Taken together, these results show the potential of AgNPs as an alternative to conventional antimicrobial agents that are currently used in extenders to preserve semen required for storage.

ABBREVIATIONS

AgNPs: silver nanoparticles; AMK: amikacin; AMP: adenosine monophosphate; AR: acrosome reaction; C: capacitation; CF: cefallotin; CFU: colony-forming unit; CTC: chlortetracycline; CXM: cefuroxime; DMSO: dimethyl sulfoxide; NC: non-capacitation; NOM: Norma Oficial Mexicana; PBS: phosphate buffered saline; RLUs: relative light units; ROS: reactive oxygen species; SQS: Seminal Quality System.

Rest days and storage of boar semen at 17°C: Effect on motility and sperm concentration

Boar fertility is an important factor in farm production; it is therefore of interest to determine factors which reduce the fertilising capacity of semen samples stored at 17°C for use in intrauterine insemination. This work evaluated the effect of the number of rest days between each mounting of the boar, and the number of days that the semen was stored at 17°C, on sperm motility and semen concentration. We also analysed whether the boar's age influenced the sperm concentration. The results showed that only the total motility diminished as the storage time at 17°C increased (p < .05). A low negative correlation was observed between the variables' rest days and total and progressive motility. The sperm concentration presented no relation with rest days or the boar's age. The boars' rest days had no effect on motility and sperm concentration in the males studied, allowing them to be used with the frequencies described with no effect on these parameters.

Effects of Atrazine and Fenoxaprop-Ethyl on Capacitation and the Acrosomal Reaction in Boar Sperm

Atrazine is a herbicide of the chloro-s-triazine family. It inhibits photosynthesis in plants and is an endocrine disruptor, but its effects on human health are controversial. Fenoxaprop-ethyl, an aryloxy phenoxyalkanoic acid herbicide, inhibits the biosynthesis of fatty acids and provokes depolarization of membranes. The aim of this study is to evaluate the in vitro effects of both herbicides on capacitation, spontaneous acrosome reaction (SAR) and progesterone-induced acrosome reaction (PIAR) in boar sperm. Sperm capacitation is done in TALP-HEPES media for 4 hours. Capacitation and SAR are evaluated immediately; PIAR, 30 minutes later. LC50 for fenoxaprop-ethyl is 60 mM and 40 mM for atrazine. Fenoxaprop-ethyl induces capacitation at 60 mM and SAR at all concentrations, also increases significantly PIAR. Atrazine decreased capacitation whereas increase significantly SAR and PIAR at all concentrations. It seems that fenoxaprop-ethyl and atrazine accelerate the capacitation and the acrosomal reaction, possibly via plasma membrane destabilization.

The Usefulness of Selected Physicochemical Indices, Cell Membrane Integrity and Sperm Chromatin Structure in Assessments of Boar Semen Sensitivity

The present work describes experiments undertaken to evaluate the usefulness of selected physicochemical indices of semen, cell membrane integrity and sperm chromatin structure for the assessment of boar semen sensitivity to processes connected with pre-insemination procedures. The experiments were carried out on 30 boars: including 15 regarded as providers of sensitive semen and 15 regarded as providers of semen that is little sensitive to laboratory processing. The selection of boars for both groups was based on sperm morphology analyses, assuming secondary morphological change incidence in spermatozoa as the criterion. Two ejaculates were manually collected from each boar at an interval of 3 to 4 months. The following analyses were carried out for each ejaculate: sperm motility assessment, sperm pH measurement, sperm morphology assessment, sperm chromatin structure evaluation and cell membrane integrity assessment. The analyses were performed three times. Semen storage did not cause an increase in the incidence of secondary morphological changes in the group of boars considered to provide sperm of low sensitivity. On the other hand, with continued storage there was a marked increase in the incidence of spermatozoa with secondary morphological changes in the group of boars regarded as producing more sensitive semen. Ejaculates of group I boars evaluated directly after collection had an approximately 6% smaller share of spermatozoa with undamaged cell membranes than the ejaculates of boars in group II (p≤0.05). In the process of time the percentage of spermatozoa with undamaged cell membranes decreased. The sperm of group I boars was characterised with a lower sperm motility than the semen of group II boars. After 1 hour of storing diluted semen, the sperm motility of boars producing highly sensitive semen was already 4% lower (p≤0.05), and after 24 hours of storage it was 6.33% lower than that of the boars that produced semen with a low sensitivity. Factors that confirm the accuracy of insemination male selection can include a low rate of sperm motility decrease during the storage of diluted semen, low and contained incidence of secondary morphological changes in spermatozoa during semen storage and a high frequency of spermatozoa with undamaged cell membranes.

Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods

Wysokińska, A. and Kondracki, S. 2014. Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods. Can. J. Anim. Sci. 94: 601–606. The present study was carried out to assess changes in sperm cell membrane integrity occurring during the storage of semen collected from genetically different domestic male pigs. The study was aimed at assessing differences in the course of changes in the integrity of cell membranes in spermatozoa produced by males with different degrees of genetic diversity (pure-bred males, two-breed hybrids and multi-breed crosses) and testing the usefulness of two methods of sperm cell membrane integrity evaluation, based on material collected from genetically different males. The experiments were conducted on 56 ejaculates collected from 28 domestic male pigs. The examination of sperm cell membrane integrity was performed three times for each ejaculate, i.e., after 1 h, after 24 h and after 48 h from collection. The preparations for analysing cell membrane integrity were made using two methods: the SYBR 14/PI method and the eosin–nigrosin method. It was found that both SYBR 14/PI and eosin–nigrosin staining methods make it possible to successfully assess the integrity of the plasma membrane of domestic pig sperm cells under in vitro conditions. Hybrid pig spermatozoa, especially those from multi-breed crosses, better retain the integrity of their plasmalemmas than the spermatozoa of pure-bred boars. The ejaculates of Hypor cross-breed boars assessed after 1, 24 and 48 h of storage contain more spermatozoa with intact cell membranes than the ejaculates of pure-bred Duroc and Pietrain boars. The ejaculates of Hypor boars also show fewer decaying spermatozoa than those produced by pure-bred boars.

Effect of porcine follicular fluid proteins and peptides on oocyte maturation and their subsequent effect on in vitro fertilization

The follicular fluid (FF) is a microenvironment that contains molecules involved in oocyte maturation, ovulation, and fertilization. Characterizing the proteins and peptides present in the FF could be useful for determining which proteins and peptides to use as a supplement for culture media. Biologically active peptides produced during the maturation or degradation of functional proteins are called cryptides. The aim of this study was to identify the proteins and cryptides in porcine FF that could stimulate porcine oocyte in vitro maturation (IVM) and in vitro fertilization (IVF) when added to culture maturation medium. Five FF protein fractions (F1-F5) were obtained by ionic exchange chromatography, resolved by SDS-PAGE, and identified by tandem mass spectrometry. These fractions had effects on IVM and/or IVF. The F1 fraction, which was composed of immunoglobulin fragments, cytokeratin, transferrin, and plasminogen precursor increased IVM and IVF. The F2, F3, and F4 fractions reduced the percentage of oocytes in first metaphase. Additionally, the F3 fraction, which was composed of immunoglobulins and transthyretin, interfered with germinal vesicle breakdown. The F5 fraction, which was mainly composed of serum albumin and keratin, favored germinal vesicle breakdown and promoted IVM. Most of the 31 proteins which were associated with the immune response and inflammatory processes could be related to oocyte maturation and fertilization. Some of the identified proteins were present in more than one fraction; this could be explained by a change in their isoelectric points, because of the loss of part of the amino acid sequence or a change in the glycosylation status of the protein. Improved oocyte IVM and IVF will increase embryo production, which in turn will contribute to the efficiency of assisted reproduction in various mammalian species.

Combination of hypoosmotic swelling/eosin Y test for sperm membrane integrity evaluation: correlations with other sperm parameters to predict ICSI cycles

The objective of our study was to evaluate the accuracy of the combination of hypoosmotic swelling (HOS) and eosin Y (Ey) exclusion tests to predict the ICSI cycles' outcome and its correlations with other sperm parameters. The functional and structural integrity of sperm membrane was evaluated with the combined HOS/Ey test in 95 ICSI cycles and the results were correlated with other sperm parameters, including concentration, motility, strict morphology, and total motile sperm count. The combined HOS/Ey test was evaluated for the prediction of the ICSI cycles' outcome parameters including fertilization, cleavage, and pregnancy rates. The HOS/Ey test presented significant relationships with concentration, motility, and strict morphology (p < 0,0001) but it couldn't predict the fertilization, cleavage, and pregnancy outcomes of ICSI cycles. The combined HOS/Ey test has strong correlations with motility and strict morphology parameters of sperm samples but is not sufficiently sensitive to estimate the outcome of ICSI cycles.