Effect of method and clinician on stallion sperm morphology evaluation

Effect of quercetin, L-ergothioneine and H89 on sperm motility and kinematic pattern, plasma membrane functionality and in vitro heterologous fertilizing capacity of cryopreserved equine semen

Semen cryopreservation causes extensive chemical and physical damage to sperm structure, which generates premature aging and reduces viability and fertility of spermatozoa. The addition of antioxidants to freezing extenders can reduce the oxidative damage caused by excessive generation of reactive oxygen species (ROS), and the premature aging could be reduced by adding an enzyme inhibitor that prevents an anticipated capacitation. The aim of this study was to evaluate the in vitro effect of quercetin (Q), L-ergothioneine (E) and H89 addition to cryopreserved equine spermatozoa. Six experimental groups were stablished: control, Q, E, H89, H89Q and H89E. The analyzed parameters were sperm motility and kinematic using computer assisted sperm analysis (CASA), plasma membrane functionality with the hypoosmotic swelling test (HOST) and fertilizing capability with in vitro heterologous fertilization. Quercetin reduced curvilinear velocity (VCL) and increased beat-cross frequency (BCF), while its combination with H89 (H89Q) reduced total motility, progressive motility, VCL and hyperactive sperm (HA). Likewise, H89 and its combination with E (H89E) decreased VCL and amplitude of lateral head displacement (ALH). No significant differences were observed among treatments for membrane functionality and fertilizing capacity of sperm. In conclusion H89 in combination with Q and E reduced sperm motility or some kinematic parameters. However, they did not influence plasma membrane functionality and in vitro fertilizing capacity of frozen-thawed equine semen.

Morphology and morphometry of sperm in Kurdish stallions, a local breed from western Iran

The present work was designed for a thorough investigation into the sperm morphology and morphometry of Kurdish stallions. The semen samples were collected from 10 Kurdish stallions. Three preparations from each ejaculate were stained with eosin-nigrosin (EN), Diff-Quik (DQ) and Rose Bengal (RB). The area, perimeter, length and width of the sperm head as well as tail length and total sperm length were measured. The parameters ellipticity, elongation, roughness and regularity were calculated. The morphology of sperm was also investigated under scanning and transmission electron microscopes. DQ and RB provided more clarified images for examining sperm structures compared to the EN method. The head length, head width, area and perimeter in EN were significantly higher than those in DQ and RB (p ≤ .05). Furthermore, the difference in head width, head area and head perimeter between DQ and RB was not significant (p ≥ .05). The tail length and total sperm length in all methods were close together (p ≥ .05). The highest percentage of normal sperm was seen in DQ and RB methods (82.55 ± 2.88 and 88.31 ± 5.19) respectively. The highest values for ellipticity, elongation and regularity were found in RB, whereas the highest value for roughness was measured in EN. Tail defects including coiled tails, and folded midpieces were the most frequent. Scanning electron microscope revealed two types of head shapes: heads with round anterior border, and heads with flat anterior border. The results indicated that despite the routine use of EN for morphological assessment of stallion sperm, RB and DQ can be considered for more clarified details of sperm structure including acrosome and midpiece. Furthermore, the Kurdish stallion sperm has morphometric traits in the normal range established for stallions; yet, some traits were larger than those reported for other breeds. It seems that the sperm of the Kurdish stallion has a longer head and tail in comparison with other horse breeds.

Assessment of the stallion sperm acrosome in two different extenders: Spermac stain in comparison with PNA/PSA/PI triple-staining

Since the stallion acrosome is very small compared to other species and cannot be properly assessed without additional staining, several labelling techniques were developed to facilitate its assessment. The aim of this study was to compare the Spermac stain (Minitüb GmbH) and a PNA/PSA/PI triple-staining detected by flow cytometry with regard to method agreement for detecting non-intact acrosomes within two different extenders. For this purpose, eighteen stallion ejaculates were split in half and diluted with the semen extenders EquiPlus or Gent (Minitüb GmbH) to a final concentration of 50 × 106  sperm/mL, respectively. Subsequently, 126 semen samples were stained with both methods between 4 and 240 h (mean: 63.8 ± 48.9 h) after semen collection. Calculated Intraclass correlation coefficients revealed excellent correlations between both methods for EquiPlus (r = .77, p < .001) and fair correlations for Gent (r = .49, p < .001). Interestingly, flow cytometry detected more non-intact acrosomes in EquiPlus than in Gent (p < .001), whereas the Spermac stain showed no differences (p = .902) between extenders. The poorer method agreement in Gent could be caused by egg yolk artefacts, which made interpretation difficult, so flow cytometry might be preferred. The differences in detected non-intact acrosomes between extenders highlighted the importance of establishing adapted laboratory protocols for different extender types in order to generate comparable results.

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.

A matter of agreement: The effect of the technique and evaluator on the analysis of morphologic defects in stallion sperm

Analysis of sperm morphology is an important part of the stallion breeding soundness evaluation since it provides an objective measure of a stallion's sperm quality and is one of many factors that estimate a stallion's fertility potential. To describe the effect of sperm quality level on the technique (Differential Interference Contrast - DIC; Phase-contrast - PH; Dip-Quick staining - DQ; and eosin-nigrosin staining - EN; semen samples fixed in buffered-formal saline) and evaluator (three evaluators; using only DIC), stallions were categorized based on sperm quality into three categories: High: >57% normal sperm, Moderate: 23-56% normal sperm, or Low: <23% normal sperm (four stallions per category). The data were analyzed using three different statistical methods: Analysis of Variance (ANOVA), correlative analysis, and Bland-Altman method (agreement). A higher level of agreement among techniques was observed between DIC and PH for morphologically normal sperm. The agreement between the alternative methods (EN, DQ, or PH) and the standard method (DIC) varied, depending on the sperm quality level (High, Moderate, or Low). Some morphological defects (e.g., AH, AMP) were constantly underestimated with the staining methods (DQ, EN) compared to DIC and PH, particularly in ejaculates with low sperm morphology. Underestimation of some abnormalities, due to the technique or the evaluator, has the potential to alter the clinical interpretation of stallion fertility.

Donkey semen cryopreservation: Alternatives with permeable, non-permeable cryoprotectants and seminal plasma

Cryopreservation of semen is an important technique to preserve genetic material. Yet, pregnancy rates in jennies after artificial insemination with frozen-thawed donkey semen are poor. This condition has been attributed to the impact of permeable cryoprotectants, that could cause high post-breeding endometritis. Removal of seminal plasma (SP) prior to semen freezing process is another contributing factor. SP is involved in a multitude of sperm functions and events preceding fertilization and has a mediating effect of sperm capacitation and postcoital uterine inflammatory response. The aim of this study was to evaluate different alternatives in donkey semen cryopreservation with permeable, non-permeable cryoprotectants, BSA and SP. Thirty ejaculates from 10 donkeys were cryopreserved with different combinations of dimethylformamide (DMF, 5%), sucrose (SUC, 200 mM) and homologous SP (10%): DMF (T1), DMF/SP (T2), SUC/BSA (T3), SUC/BSA/SP (T4), DMF/SUC/BSA (T5), DMF/SUC/BSA/SP (T6), DMF/BSA (T7) and DMF/BSA/SP (T8). After thawing, sperm motility and kinetics were assessed by computerized semen analysis. Sperm vitality (SV) was evaluated by fluorescence microscopy, functional membrane integrity (FMI) by the HOST test, abnormal morphology by eosin-nigrosin staining and sperm membrane stability by flow cytometry. For statistical analysis, sperm quality indexes (SQi) were obtained, general linear models were carried out and mean comparisons were made by the Tukey test. T1, T2, T5, T6, and T7 had higher and equivalent results for motility, most kinetic parameters and function membrane integrity. Cryopreservation of donkey semen without permeable cryoprotectant (T3 and T4) showed a reduction in motility, kinetics, SV, FMI and SQi. T5 showed a reduction in progressive motility, sperm velocities, IMF and SQi compared to other DMF treatments. T6 and T8 achieved higher SQi values compared to T1, but they were not different compared to T2 and T7. T1 had a smaller sperm population with low-M540 compared to T3. It is concluded that the use of permeable cryoprotectant is essential to achieve higher post-thaw quality of donkey semen. In addition, the combined use of BSA, SUC and/or PS may provide additional sperm protection compared to the individual use of DMF.

Morphometry of Boar Spermatozoa in Semen Stored at 17 °C—The Influence of the Staining Technique

Simple Summary

To obtain satisfactory results in artificial insemination, it is necessary to use high-quality ejaculates for the production of insemination doses and then maintain the biological value of the sperm during storage. Boar spermatozoa, owing to the specific structure of the cell membrane, are particularly sensitive to temperature changes. For this reason, cryopreservation cannot be used in artificial insemination practice, and there may be limitations to successful storage of semen in a liquid state. The practice of using boar semen for artificial insemination does not include analyses of the effect of storage time of boar semen on sperm dimensions. Therefore, the aim of the study was to analyse the morphometry of sperm during storage of liquid boar semen. An attempt was also made to evaluate the suitability of three staining methods for assessment of boar sperm morphometry. The morphometric dimensions of boar sperm were shown to change during storage of liquid semen. These changes affected the sperm head more than the tail and were due to the staining method used. The analyses are very important as they provide more information about the morphometric dimensions of the sperm during preservation of boar semen. The applied sperm staining techniques allows for a more accurate assessment of male reproductive cells.

Abstract

The aim of the study was to assess the morphometry of sperm during storage of liquid boar semen at 17 °C. An attempt was also made to evaluate the suitability of three staining methods for assessment of boar sperm morphometry. The study was carried out on 20 Landrace boars. Semen was collected from the boars every 5 days by the manual method. Four ejaculates from each boar were analysed (80 ejaculates in total). Analyses were performed five times: at 1 h, 24 h, 48 h, 96 h, and 168 h after semen collection. Blisters with insemination doses were opened immediately before the analyses. From each insemination dose, smears were prepared for morphometric evaluation of sperm, which were stained by three methods (eosin-nigrosin—EN, eosin-gentian—EG, and SpermBlue—SB). Morphometric measurements of 15 randomly selected sperm with normal morphology were performed on each slide. The morphometric measurements included the following parameters: sperm head length, width, area, and perimeter; tail length; and total sperm length. The results of the morphometric measurements were used to calculate the head shape index. The morphometric dimensions of the sperm were shown to change during storage of semen at 17 °C. The extent of these changes, however, depended on the staining method used, as the three methods result in different morphometric dimensions of sperm, in the case of both the head and the tail. In the slides stained by the eosin-nigrosin method, the dimensions of the head and tail were smaller at every time of storage than in the slides stained by the SpermBlue and eosin-gentian methods.

Effect of supplementation of freezing media with isoespintanol on functional integrity of equine semen

Adding antioxidants to semen extender has become one of the major strategies to reduce the damage caused by freezing to stallion sperm. Isoespintanol (Iso) is a natural antioxidant that is known as a good free radical scavenger. The aim of this research was to evaluate the effect of supplementation of freezing media with Iso on functional integrity of equine semen. Semen from five Colombian Creole horses was frozen with 0, 10, 20, 30, 40 and 50 µM Iso. Post-thawing motility and kinetics, structural membrane integrity (SMI), normal morphology (NM) and functional membrane integrity (FMI) of sperm were evaluated. Seminal quality (SQi) and seminal velocity (SVi) indexes were calculated. Through a flow cytometric analysis, mitochondrial membrane potential (ΔΨM), viability and DNA integrity of frozen-thawed semen were assessed. General linear models were adjusted, and means comparisons were performed using Tukey’s test. The significance level was P<0.05. No differences for post-thaw sperm quality parameters were found, except for total motility, which showed a reduction by adding 40 µM Iso (P<0.05). However, the estimation of indexes, showed that supplementation with 20 or 30 µM Iso before semen freezing, can increase post-thaw SQi and SVi values of some horses. A higher proportion of high-∆ΨM sperm for 20 µM Iso was found. It is concluded that Iso can improve the quality and mitochondrial activity of frozen-thawed equine semen, however its effect can vary according to the horse and in high concentrations it could have detrimental effects.

New Sperm Morphology Analysis in Equids: Trumorph® Vs Eosin-Nigrosin Stain

The evaluation of the male fertility potential is based on the analysis of the basic spermatic characteristics of concentration, motility and morphology. Thus, the study of sperm morphology is a fundamental element in the seminal analysis, but its real meaning has been biased by the techniques used for its evaluation. These techniques involve dehydration phases and subsequent staining, which involves the production of artifacts. The aim of the study is to compare two methods for equid semen morphology evaluation, Trumorph^® using living sperm vs. eosin-nigrosine stain. A total of 49 ejaculates from stallions and donkeys were used. After semen collection and dilution, an aliquot was placed on the slide and introduced in the Trumorph^® device. Then observation was made with a 40x objective and negative phase-contrast microscope. Another aliquot was stained using eosin-nigrosine stain and viewed using 100× magnification. Well-formed sperm were observed, and different abnormalities were identified using Trumorph^®. The use of eosin-nigrosin staining method and Trumorph^® led to the same results and both techniques can be used for stallion and donkey sperm morphological analysis. However, considering the fact that Trumorph^® uses living sperm helps prevent sperm cell alteration during sample preparation. Therefore, Trumorph^® can be a good alternative to the conventional staining method, which provides a quick test on live sperm.

Assessment of the Morphometry of Heads of Normal Sperm and Sperm with the Dag Defect in the Semen of Duroc Boars

Introduction

The Dag defect is one of the primary morphological defects in sperm correlating with reduced fertility. This defect is found in the spermatozoa of many livestock species. The aim of the study was to assess the morphometry of the heads of normal sperm and sperm with the Dag defect in the semen of Duroc breeding boars.

Material and Methods

Sperm morphology was examined in ten ejaculates each from 12 Duroc boars. In total, 3,600 morphologically normal sperm and 838 sperm with the Dag defect were evaluated. The area, perimeter, length and width of the sperm head were measured and these basic morphometric parameters were used to calculate four additional shape indices characterising the sperm head, i.e. ellipticity, elongation, roughness and regularity.

Results

Sperm with this defect had markedly smaller heads, 0.32 μm shorter and 0.19 μm narrower than the heads of sperm with normal morphological structure. The heads of sperm with the Dag defect also had a 1.1μm smaller perimeter and a 2.5 μm² smaller surface area than the heads of morphologically normal sperm.

Conclusions

The Dag defect is found in boar sperm irrespective of the age of the individual. It affects the morphology of the sperm head.

Evaluation of the Morphometry of Sperm from the Epididymides of Dogs Using Different Staining Methods

Evaluation of sperm morphometry is an important criterion in the diagnosis of a male animal's suitability for breeding. The aim of the study was to evaluate the morphometry of sperm from the epididymides of dogs subjected to routine castration using various staining methods. The study was carried out on semen collected from ten healthy dogs. Gonads were obtained from each dog during routine castration at a veterinary surgery. Then, the epididymides (caput, corpus, cauda) were isolated from the gonads, semen was collected from them and microscope slides were prepared. The slides for evaluation of sperm morphometry were prepared by four methods: DiffQuik, SpermBlue, eosin-nigrosin and eosin-gentian. A total of 2400 sperm were analyzed (240 sperm from the dog). The sperm collected from the caput and corpus of the epididymis were found to have larger heads and tails than those collected from the cauda of the epididymis. The staining method was shown to affect the morphometry of sperm taken from the epididymides of dogs. The staining methods differentiate the dimensions of the head of sperm in different parts of the epididymis but do not affect the length of the sperm tail. The occurrence of differences in the head dimensions of sperm may be linked to the use of different fixatives and chemical reagents in the staining procedure. Sperm stained by the EN method had the smallest head and tail dimensions. The greatest head area was noted in the sperm stained by the EG method. In the slides stained by the SB method, the sperm heads were relatively long but narrow. The methods used are suitable for the evaluation of sperm structure, and the possibility of using all four methods enables a full characterization of sperm collected from the caput, corpus and cauda of the epididymides of dogs.

Cholesterol Loaded Cyclodextrin Supplementation Enhances the Cholesterol-to-Phospholipid Ratio and Diminishes Oxidative Stress in Jack Spermatozoa During Cryopreservation

The present study was conducted with the hypothesis that addition of cholesterol to the extender would stabilize the sperm membranes by increasing the cholesterol-to-phospholipid (C:P) ratio and would result in an improved post-thaw semen quality and reduce oxidative stress in the jack (Martina franca) semen. Forty-eight ejaculates from six jacks were collected and analyzed for the present study. The freshly collected semen sample of each jack stallion was divided into five equal fractions after addition of the primary extender without cholesterol-loaded cyclodextrin (CLC) (C) and with 1, 1.5, 2, and 3 mg/mL CLC to obtain 120 × 10⁶ sperm/mL spermatozoa concentration. The semen was cryopreserved using customized freezing protocols. Evaluation of seminal parameters, the C:P ratio, and the oxidative status of jack spermatozoa was analyzed at all stages of cryopreservation. The oxidative status in the jack semen was evaluated by measuring malondialdehyde, glutathione and total antioxidant capacity levels. The results indicated that the mean percent values for various seminal quality parameters and the oxidative parameters were found to be significantly higher (P < .05) in CLC-treated groups with the highest values for 2 mg of CLC/120 × 10⁶ spermatozoa. In conclusion, the present study revealed that the supplementation of CLC before cryopreservation has significantly reduced the oxidative stress and also increased the C:P ratio during semen cryopreservation process. Furthermore, a reduction in lipid peroxidation levels, reduced damage to the sperm plasma and acrosome membranes and improvement in the post-thaw sperm integrity as well as stability were recorded.

Post-thawing Sperm Quality in Chilean Purebred Stallions: Effect of Age and Seasonality

In this work, we investigated the influence of age and seasonality on sperm motility and DNA fragmentation in post-thawing semen from Chilean Purebred Stallions (CPS), a horse breed presenting the oldest genealogy record in South America with an interesting reproductive industry. Despite that semen from aged CPS is frozen all year round, there is a lack of studies characterizing the breed semen freezability in accordance with age and seasonality. Twenty fertile CPS were grouped into the young group, the middle group, and the aged group. Ten ejaculates from each stallion were obtained by using an artificial vagina during summer (December) and winter (July) and directly frozen. Subsequently, the frozen semen was thawed and analyzed by a computer-assisted semen analysis and flow cytometer assessing progressive motility, mean velocity, and DNA fragmentation spermatozoa. Kruskal-Wallis test and Pearson's correlation were used to determine statistical differences among groups and correlation among variables (P ≤ .05). Both spermatozoa motility traits decreased progressively in accordance with age and seasonality, showing the lowest values in the aged group during winter and the highest values in the young group during summer. Deoxyribonucleic acid fragmentation increased significantly in accordance with age and seasonality being highest in the aged group during winter and lowest in the young group during summer. Post-thawing sperm quality showed a negative correlation with the age of the stallions and a positive correlation with the normal sperm morphology before freezing. These results allow the conclusion that age and seasonality are important factors that need to be considered during the selection of CPS for reproductive programs.

Lyophilized seminal plasma can improve stallion semen freezability

The aim of this study was to evaluate the effect of lyophilized seminal plasma (LSP) on stallion semen freezability. Seminal plasma from 30 stallions was lyophilized to obtain a pool of LSP. Fifteen ejaculates from five stallions were supplemented before freezing with 0 mg/mL (Control), 1.44 mg/mL (LSP1), 5.04 mg/mL (LSP2) or 8.68 mg/ mL (LSP3) of LSP. Total antioxidant capacity (TAC) of LSP was assessed using Oxygen Radical Absorbance Capacity (ORAC) assay. Post-thaw motility and kinetics, sperm viability, normal morphology and membrane integrity were evaluated. Completely randomized mixed models were fitted for data analyses. The results was analyzed based on freezability of semen samples. TAC for LSP pool was 13679.4±911.6 μmol Trolox 100/g (ORAC units). Semen supplementation with LSP1 and LSP2 showed a positive effect on post-thaw total motility and membrane integrity. Supplementation with LSP3 showed a decrease in post-thaw total and progressive motility, straight line velocity and sperm viability. For poor freezability semen samples, supplementation with LSP1 and LSP2, showed higher post-thaw total motility and membrane integrity than good freezability semen samples. In conclusion, supplementation with LSP can improve the post-thaw seminal quality of stallion semen with poor freezability.

Ameliorative Effect of Ascorbic Acid and Glutathione in Combating the Cryoinjuries During Cryopreservation of Exotic Jack Semen

The present study was designed to study the adverse effects of cryopreservation and evaluation of the cryoprotective effect of reduced glutathione (GSH) and ascorbic acid (AA) supplementation on exotic jack semen in combination or alone. For this, 24 semen samples from four adult and fertile jacks were collected via artificial vagina using an estrus jenny as dummy. After semen collection, the semen was evaluated for various qualitative and quantitative parameters in fresh, cooled, and frozen-thawed semen. The semen pellet was extended with the freezing extender containing either AA (0.9 g/L), GSH (2.5 mM), or combination of both (AA 0.9 g/L + GSH 2.5 mM), and another aliquot was kept as control without adding the antioxidants. The jack semen underwent cryodamage, which was evident by the observation of significant (P < .05) decline in the seminal quantitative parameters at various stages of cryopreservation process. Prefreeze and postthaw semen evaluation revealed that the values of plasma membrane, acrosome integrity, and chromatin integrity were found to be significantly higher (P < .01) in the group of samples supplemented with the combination (0.9 g/L AA +2.5 mM GSH) than AA- and GSH-alone or control groups. Supplementation of antioxidants to the freezing extender improved jack prefreeze and postthaw semen quality with the superiority of GSH over AA alone. From the present study, it was inferred that, exotic jack spermatozoa are susceptible to injuries because of cryopreservation, but these cryo-induced damage can be ameliorated significantly (P < .05) with the use of antioxidants and contribute to the improvement of semen cryopreservation procedures.

The effect of the staining technique on morphological and morphometric parameters of boar sperm

Sperm morphology and morphometry are important parameters in predicting fertility. Sperm are considered to be normal if the shape and size of the head, midpiece and tail fall within the classification for a given species. It is important to select the appropriate technique for staining the semen of a given species, because, as many authors have pointed out, some methods work well for one species but are not suitable for analysing another. The aim of the study was to assess the morphometric parameters of boar sperm following the use of different staining techniques and to verify the hypothesis that the staining technique affects the morphometric parameters of sperm. The staining method was found to significantly affect the dimensions of the boar sperm head. The semen stained by the SpermBlue technique had the closest morphometric sperm head parameters to those of the unstained sperm, so this technique, rather than the routinely used eosin and gentian complex, should be the leading technique in the evaluation of boar sperm morphometry. Silver nitrate staining reveals the structure of the sperm in the most detail; this method can be considered universal, and can be used independently or to supplement routine diagnostics. As the staining technique should interfere as little as possible with the structure of the sperm, while revealing its morphology in as much detail as possible, it is crucial to establish the natural dimensions of the unstained sperm head before determining the optimal technique and its reference values. The recommended or most commonly-used techniques are not always the best options for the staining and analysis of sperm of a given species.

The use of two staining methods for identification of spermatozoon structure in roosters

Many of the methods used to stain semen result in very pronounced coloring of the sperm, but unfortunately they do not distinguish their individual structures, which play a key role in the fertilization process. Hence the aim of this study was to identify sperm structures using two staining techniques in the semen of roosters from breeding flocks. The subject of the study was the sperm of roosters from a Ross 308 breeding flock. To capture the differences in the dimensions of sperm subjected to the effect of different chemical substances in dyes, microscope slides were stained by two techniques: with an AgNO3 solution and by a differential method (eosin-nigrosin test). Assessment was made of the degree of coloration and the number of details that could be identified in the morphological structure of the sperm. The use of AgNO3 allowed accurate identification of the acrosome, nucleus, and midpiece, which were visible in the slides stained with eosin-nigrosin, but only in dead spermatozoa. The AGNO3 staining technique used in this study reveals the cell nucleus within the head and can be an alternative method to analysis with a scanning electron microscope. This staining technique can be used to stain sperm structures that cannot be seen in other methods of slide preparation, which means that it can be considered for routine use in assessing the fertility of roosters in breeder flocks.

Isoespintanol improves the post-thaw quality of stallion semen

The present study was conducted to assess the effect of the egg yolk powder in place of fresh egg yolk (EY) in the semen diluent on semen morphological attributes (SMAs) and mobility & velocity profiles measured by computer assisted sperm analyser (CASA) in cryopreserved mithun semen. A total of 25 ejaculates were collected through rectal massage method from five healthy mithun bulls (five ejaculates in each bull) and diluted with the standard tris citrate glycerol (TCG) extender and were splited into four equal aliquots: Gr I: control (20% EY); Gr II, III and IV contained 5, 8 and 10% EY powder, respectively. SMAs, CASA parameters were evaluated following freezingthawing of semen. Result revealed significant (p<0.05) improvement was observed in these SMAs and CASA parameters in Gr II and III as compared to Gr I and IV. It was concluded that inclusion of 5% or 8% EY powder in semen diluent holds a clear advantage and higher benefits over 20% fresh EY in cryopreservation of mithun semen.

Association of the cysteine-rich secretory protein-3 (CRISP-3) and some of its polymorphisms with the quality of cryopreserved stallion semen

Contribution of seminal plasma proteins to semen freezability has been reported in several species, suggesting these proteins as genetic markers. The aim of this study was to evaluate the relationship between cysteine-rich secretory protein-3 (CRISP-3) and some of its single-nucleotide polymorphisms (SNPs) with post-thawing semen quality in stallions. DNA was obtained from 100 stallions, regions of interest were amplified by polymerase chain reaction and sequenced. Evaluated SNPs within the equine CRISP-3 gene were CRISP3c.+199A > G (SNP1), CRISP3c.+566C > A (SNP2), CRISP3c.+622G > A (SNP3) and CRISP3c.+716A > G (SNP4). CRISP-3 protein content in seminal plasma was determined by enzyme-linked immunosorbent assay. Semen from 30 stallions was cryopreserved and post-thaw motility, kinetics, abnormal morphology (AM), sperm vitality (SV) and membrane integrity (MI) were evaluated. Generalized linear models were fitted and means were compared using Tukey’s test. Correlation and regression analyses were performed. For SNP1 and SNP3, the AA genotype had the highest results for motility and MI; for SNP2, the best results for motility and AM were obtained with the CC genotype. For SNP4, the GG genotype had the lowest results, except for MI. A high level of CRISP-3 protein in seminal plasma had the best results for motility, kinetics, SV and AM. In conclusion, there was a relationship between CRISP-3 genotype and seminal plasma protein and post-thawing semen quality in stallions.

Effects of staining method and clinician experience on the evaluation of stallion sperm morphology

Evaluation of sperm morphology is part of the assessment of fertility in human and animal reproduction. Analyses can be performed using different techniques, including the use of staining methods In our prospective study, the morphology of equine sperm was evaluated using 3 staining methods Diff-Quik, eosin-nigrosin, and SpermBlue, the latter being a relatively new stain commonly used for human sperm. Our hypotheses were that (1) SpermBlue allows easier assessment of horse sperm morphology and facilitates better identification of sperm abnormalities, and (2) sperm morphology classification differs depending on the evaluator's experience. Semen was obtained from various horse breeds; 40 samples from stallions between 2 and 15 years of age were collected during the 2016 breeding season and stored in a 2% buffered formaldehyde solution until processing. For each sample, 3 semen smears were made and stained with Diff-Quik, eosin-nigrosin, and SpermBlue. All morphological parameters were then evaluated blindly using a light microscope by a novice evaluator and a more experienced evaluator. For each slide, 200 spermatozoa were examined randomly and classified according to their characteristics. For the identification of morphologically normal spermatozoa, no significant difference between evaluators was found with any of the staining methods used. In contrast, significant differences between evaluators were observed in the classification of some anomalies affecting mainly the midpiece and the tail. Poor dye fixation was observed with SpermBlue.

Application of Two Staining Methods for Sperm Morphometric Evaluation in Domestic Pigs

Introduction

The effect of two smear staining methods on the dimensions and shape of sperm cells in the semen of domestic pigs was evaluated.

Material and Methods

The studies were carried out on 30 ejaculates collected from 15 boars, which included five Duroc boars, five Pietrain boars, and five hybrid Duroc × Pietrain boars. Each ejaculate was next sampled to make two microscopic slides, of which one was stained with eosin-nigrosin and the other with eosin-gentian dye. In total, 600 measurements of sperm cells were made. Each sperm was measured for the following morphometric parameters: head length, head width, head area, head perimeter, tail length, and the total sperm length.

Results

Sperms measured on slides stained with eosin-nigrosin showed lower dimensions as compared with those stained with the eosin-gentian dye method. Sperm stained with eosin-nigrosin had shorter and narrower heads than sperm stained with eosin-gentian dye. The method of staining, therefore, affected not only the dimensions of the sperm, but also the proportions of the dimensions defining the shape of the sperm.

Conclusions

The size and shape parameters in porcine sperm may take on different values depending on the method of semen staining. Sperm cells stained with eosin-nigrosin are smaller than the sperm stained with eosin-gentian dye. The sensitivity of the sperm to the type of dye used for the fixation may be associated with genetic factors.

Semen characteristics and refrigeration in free-ranging giant anteaters (Myrmecophaga tridactyla)

The giant anteater (Myrmecophaga tridactyla) is considered vulnerable to extinction. Scientific data on the reproductive parameters of this species are scarce. Semen from eight free-ranging giant anteaters was collected to establish its characteristics and the effects of cooling and storage at 5 °C after dilution with the BotuCrio extender without cryoprotectant. The ejaculate presented two distinct sequential fractions, including a whitish fraction, which was milky and rich in sperm cells, and a gel fraction, which was colorless, viscous, and azoospermic. The mean ± standard error of the mean values of the seminal characteristics were as follows: volume of the first fraction, 0.75 ± 0.1 mL; motility, 75 ± 2.9%; vigor, 3.2 ± 0.3; sperm motility index, 68.8 ± 4.3; concentration, 108.5 ± 13.4 × 10(6)/mL; plasma membrane integrity index, 71 ± 4.0%; spermatic defects detected using modified Karras staining, 35.5 ± 3.3%; and spermatic alterations identified by differential interference contrast microscopy, 48.3 ± 6.8%. During refrigeration, the semen presented decreasing motility from 0 to 18 hours, sperm motility index decreased from 0 to 24 hours, and vigor did not change in the first 6 hours and then decreased to 18 hours.

Evaluation of morphological criteria of sperm quality before in vitro fertilization and intracytoplasmic sperm injection

The quality of sperm has a direct influence on the fertilization and developmental competence of embryos. In the literature we did not find defined criteria for evaluation of normal sperm parameters in various species of domestic mammals. Therefore we attempted to review evaluation of criteria of morphologically normal human sperm and their abnormalities. All sperm cells observed in the stained sample are classified as normal or abnormal. Any abnormalities in morphology of sperm have a negative effect on the outcome in in vitro fertilization and intracytoplasmic sperm injection. Abnormal sperm are categorized into subgroups according to the observed defects (concerning the head and/or midpiece and/or tail). Most morphologically abnormal sperm have multiple defects. This article can be considered as guideline for the manual of sperm quality evaluation in different species of domestic mammals.

Use of two conventional staining methods to assess the acrosomal status of stallion spermatozoa

REASONS FOR PERFORMING STUDY

The acrosome is a highly specialised region of the spermatozoon that is essential for fertilisation. Defects or dysfunction of this structure have been associated with fertility problems in man and various domestic species including stallions. Current methods of evaluating the acrosome of stallion spermatozoa are time consuming and require specialised equipment, which is cost prohibitive to the average practitioner.

OBJECTIVES

To evaluate 2 conventional stains (Dip Quick and Spermac) and determine their usefulness in assessing acrosome integrity in stallions as compared with specific acrosomal labelling with a fluorescein-conjugated lectin - a method that has been validated for acrosome status evaluation in stallions.

STUDY DESIGN

In vivo experimental design.

METHODS

Semen from 6 mature Miniature horse stallions of known fertility was collected on 5 separate occasions. To increase the number of reacted acrosomes, portions of each ejaculate were incubated with the calcium ionophore, A23187. Ejaculates were divided and semen samples were processed according to recommendations for fluorescein-conjugated peanut lectin, Pisum sativum agglutin, Dip Quick, and Spermac staining methods. Slides were evaluated independently by 2 separate investigators. Spermatozoa were classified as having intact, reacting, reacted or defective acrosomes.

RESULTS

All parameters obtained by both investigators, using all 3 staining methods were highly correlated (P<0.001). There was no statistical difference (P>0.05) between investigators or staining method for the percentages of intact or reacted acrosomes. However, there was a significant difference between investigators and staining methods for determining reacting acrosome percentages (P<0.05).

CONCLUSIONS

Dip Quick and Spermac stains are useful for determining intact vs. reacted acrosomes for stallion spermatozoa.

The usefulness of Real Time Morphology software in semen assessment of teratozoospermic boars

The aim of the present study was to compare two different techniques of sperm cell morphology evaluation in teratozoospermic boars: computer assisted semen morphology analysis and conventional assessment of stained semen smears. The semen samples were collected manually from 30 boars with reduced semen quality. In all samples the percentage of morphologically normal spermatozoa was below 70%. Computer assisted semen morphology assessment was performed using the Real Time Morphology (RTM) software (IVOS ver. 12.2, Hamilton Thorne Bioscience). The assessment was made by phase contrast optics, with the magnification of 20 x 3.8 and without staining. Conventional morphology assessment was performed by bright field microscopy with 1,000 x magnification after staining with Giemsa. At least 200 spermatozoa were evaluated per slide in both methods. The Bland-Altman plot indicated a general agreement between both methods of sperm morphology evaluation. The plots revealed the widest limits of agreement (mean ± 1.96 SD) for the percentage of midpiece anomalies (from -16 to 13.2), and the narrowest for the percentage of looped tail (from -1.49 to 1.09). The Bland Altman plot indicates general agreement between RTM and Giemsa staining in the percentage of major and minor defects. However, it was not possible to evaluate acrosomes using RTM. Otherwise, RTM proved to be a valuable tool in sperm morphology assessment, with accuracy equal to typical conventional methods.