Capacitation of ram spermatozoa promotes changes in energy metabolism and aquaporin 3 and is affected by individual testosterone variations.

BACKGROUND: Recently, the metabolic pathways involved in energy production and the role of aquaglyceroporins in capacitation-associated events have been studied in humans and mice. However, little is known about these in ram spermatozoa. OBJECTIVE: The present study investigated bioenergetic and aquaglyceroporin 3 variations during in vitro capacitation of ram spermatozoa. In addition, differences in testosterone levels between males were examined to determine their influence on capacitation-like changes. MATERIALS AND METHODS: Spermatozoa obtained from nine rams (ejaculates = 36) were incubated for 180 min in three different media (control, capacitating, and aquaglyceroporin-inhibitor media) at 38.5°C. At 0 and 180 min of incubation in each medium, sperm viability, kinetics, chlortetracycline patterns, adenosine triphosphate concentration, lactate excretion (final subproduct of glycolysis), and immunolocalization of aquaporin 3 were evaluated. RESULTS: The increment of the capacitated spermatozoa-chlortetracycline pattern and the hyperactivated-like movement characterized by the highest curvilinear velocity and amplitude of lateral head displacement and the lowest linearity was only recorded after 180 min in the capacitating medium. At this time and conditions, adenosine triphosphate content and lactate excretion decreased, whereas the aquaglyceroporin 3 location in the midpiece and principal piece increased compared to 0 min. Such changes were not observed in the control medium over time. Incubation in the aquaglyceroporin-inhibitor medium for 180 min reduced drastically sperm motility and adenosine triphosphate content compared to the other media. Testosterone analysis revealed a significant individual variability, which was also present in all sperm parameters evaluated. Furthermore, testosterone was negatively correlated with adenosine triphosphate content but positively correlated with lactate excretion levels, sperm viability, motility, capacitated sperm-chlortetracycline pattern, and aquaglyceroporin 3 immunolabeling in the midpiece and principal piece. CONCLUSION: Despite individual differences, capacitation of ram spermatozoa increases adenosine triphosphate consumption, energy metabolism, and aquaglyceroporin 3 location in the midpiece and principal piece, which seems to be related to the acquisition of hyperactivated-like motility. Furthermore, testosterone levels may serve as a valuable tool to select those males with a greater sperm metabolism rate and fertilizing capacity.

Successful ultrasound-guided ovum pick-up (OPU) and subsequent in vitro embryo production in a domestic cat.

Ovum Pick Up (OPU) is a minimally invasive technique widely used in cattle and mares for oocyte retrieval, involving ultrasound-guided puncture of ovarian follicles. It has been demonstrated that this technique is safe for its repeated use in the same female without affecting her reproductive health, allowing for the retrieval of oocytes in individuals regardless of their reproductive status. The oocytes obtained through OPU can subsequently be used for in vitro embryo production (IVP) using assisted reproductive techniques (ARTs) or be cryopreserved in biobanks for their future use. Traditionally, the minimally invasive technique of choice performed in vivo in domestic and wild felines was LOPU (laparoscopic-guided ovum pick up). The present study was designed to explore if ultrasound-guided OPU in the domestic cat is safe and effective. In an initial series of ex vivo experiments (n = 92 ovaries, n = 434 oocytes), the effect of different aspiration pressures for oocyte collection was explored. These experiments identified 43 mmHg as the optimal aspiration pressure, resulting in the highest recovery rate and a favorable maturation and blastocyst rate. Subsequently, 16 grade I and II oocytes were retrieved by OPU and 101 oocytes were retrieved following ovariectomy and slicing. Sixteen oocytes obtained with each technique were subjected to in vitro maturation (IVM) and in vitro fertilization (IVF). A total of 14 presumptive zygotes were selected for in vitro culture (IVC) from each group (OPU and slicing), obtaining a cleavage rate of 57.1 % and 64.2 %, a morula rate of 28.5 % in both groups, and a blastocyst rate of 7.14 % and 14.2 % respectively. The hormonal stimulation protocol was well-tolerated, with no adverse effects observed. Moreover, no complications arose during the ovariectomy performed post-OPU. The use of this technique in domestic cats represents a significant step forward in terms of safety, replicability, and invasiveness, serving as a valuable model for its application in wild felids species. Additional research involving a greater number of animals is required to validate these encouraging findings.

Perceptions of Animal Welfare on Livestock: Evidence from College Agronomy Students in Costa Rica.

Ethical considerations regarding our treatment of animals have gained strength, leading to legislation and a societal focus across various disciplines. This is a subject of study within curricula related to agri-food sciences. The aim was to determine the perceptions of agronomy university students concerning animal welfare in livestock production systems. A survey was conducted to encompass various aspects, from participants' sociodemographic attributes to their attitudes and behaviors regarding animal welfare and the consumption of animal products. Statistical analysis, performed using R software, delved into the associations between participants' characteristics and their perspectives on the ethical, bioethical, and legal dimensions of animal welfare. Associations between demographic factors and ethical viewpoints among students were identified. Gender differences emerged in animal treatment perceptions, while rural and urban environments impacted perspectives on various animals. Bioethical considerations revealed distinctive disparities based on gender and education in concerns regarding animal welfare, value perceptions, evaluations of animal behaviors, and opinions on animal research. It is crucial to distinguish between animal welfare and the ethical considerations arising from coexisting with sentient beings capable of experiencing suffering. Ethical theories provide a lens through which we perceive our obligations toward animals. The responsibility to ensure animal welfare is firmly rooted in recognizing that animals, like humans, experience pain and physical suffering. Consequently, actions causing unjustified suffering or mistreatment, particularly for entertainment purposes, are considered morally unacceptable.

Exploration of semen quality analyzed by casa-mot systems of brahman bulls infected with BLV and BHV-1.

Enzootic bovine leukosis virus (BLV) and bovine herpesvirus 1 (BHV-1) are very important infectious agents for the livestock industry worldwide. The present study aimed to explore the association between natural exposure to BLV and BHV-1 with sperm quality analyzed by Computer-Assisted Semen Analysis (CASA) systems. Ten sexually mature Brahman bulls, with sanitary status BLV+/BHV-1+ (n = 2), BLV-/BHV-1+ (n = 6) and BLV-/BHV-1- (n = 2) were evaluated twice, 30 days apart. Results showed that sanitary status of each bull was not associated with semen quality. It was found that the quality of the semen from the second collection was better due to the interruption of sexual rest. The evidence thus revealed that a bull infected with BLV generated good-quality contaminated semen and, therefore, that it is essential to detect contaminated seminal samples to prevent the spread of BLV. A multivariate analysis showed the presence of four sperm subpopulations in Brahman bulls that differ significantly in their kinematic patterns and with respect to sanitary status (P < 0.05), indicating that infection-free and seronegative bulls present the best kinematic parameters, which improved discrimination of sperm quality according to sanitary status. Overall, the analyses indicate that the seropositive-infected bulls with BLV and BHV-1 should be excluded from beef cattle farms.

Sperm Chromatin Status and DNA Fragmentation in Mouse Species with Divergent Mating Systems.

Sperm DNA integrity and chromatin status serve as pivotal indicators of sperm quality, given their intricate link to sperm function, embryo development, and overall fertility. Defects in chromatin compaction, which are often associated with compromised protamine content, can lead to damaged DNA strands. In this study, the chromatin status and possible correlation with DNA damage was assessed in males of three mouse species: Mus musculus, M. spretus, and M. spicilegus. We employed various staining methods, including aniline blue, methylene blue (Diff-Quik), toluidine blue, and chromomycin A3, to assess chromatin compaction in cauda epididymal sperm. Samples were also analyzed by the sperm chromatin structure assay (SCSA) to estimate DNA fragmentation (%tDFI, %HDS). Analyses were carried out on freshly collected sperm and cells incubated for 3 h in a HEPES-buffered modified Tyrode's medium simulating conditions of the female reproductive tract. Notably, the analysis of chromatin status yielded minimal abnormal values across all three species employing diverse methodologies. SCSA analyses revealed distinct variations in %tDFI between species. Following sperm incubation, the percentages of sperm stained with methylene blue exhibited differences among the species and were significantly correlated to the DNA fragmentation index. HDS demonstrated correlations with the percentages of sperm stained by aniline blue, methylene blue, and chromomycin A3. Overall, chromatin compaction was high across all species, with limited differences among them. The relationship between chromatin status and DNA integrity appeared to be related to levels of sperm competition among species.

Sperm Capacitation and Kinematics in Phodopus Hamsters.

This study was designed to analyze changes in the spermatozoa of three species of Phodopus hamsters incubated under different conditions. Cauda epididymal sperm were incubated for 4 h in modified Tyrode's medium containing albumin, lactate, pyruvate, and Hepes (mTALP-H), in the same medium with the addition of bicarbonate (mTALP-BH), or with bicarbonate and 20 ng/mL of progesterone (mTALP-BH+P4). Media with bicarbonate are believed to promote capacitation in rodent species. Sperm motility, viability, capacitation patterns, and kinematics were assessed at different times. Capacitation in live cells was quantified after staining with Hoechst 33258 and chlortetracycline. Patterns believed to correspond to non-capacitated cells (F pattern), capacitated, acrosome-intact cells (B pattern), and acrosome-reacted cells (AR pattern) were recognized. Kinematics were examined via computer-assisted sperm analysis (CASA). The results showed a decrease in total motility in all three species in different media, with a sharp decrease in progressive motility in bicarbonate-containing media (without or with progesterone), suggesting hyperactivated motion. However, none of the other signs of hyperactivation described in rodents (i.e., decrease in STR or LIN, together with an increase in ALH) were observed. F pattern cells diminished with time in all media and were generally lower in P. roborovskii and higher in P. campbelli. B pattern cells increased in mTALP-BH media in all species. Progesterone did not enhance the percentage of B pattern cells. Finally, AR pattern cells increased in all species incubated in different media, showing the highest percentage in P. roborovskii and the lowest in P. campbelli. Comparisons between media revealed that there were higher percentages of F pattern cells and lower percentages of B pattern cells over time in medium without bicarbonate (mTALP-H) in comparison to media containing bicarbonate (mTALP-BH; mTALP-BH+P4). Overall, changes consistent with the acquisition of capacitation and development of hyperactivated motility were found; however, further studies are required to better characterize media necessary to support the pathways involved in these processes in Phodopus species.

Adenylate kinase 9 is essential for sperm function and male fertility in mammals.

Despite passing routine laboratory tests for semen quality, bulls used in artificial insemination exhibit significant variation in fertility. Routine analysis of fertility data identified a dairy bull with extreme subfertility (10% pregnancy rate). To characterize the subfertility phenotype, a range of in vitro, in vivo, and molecular assays were carried out. Sperm from the subfertile bull exhibited reduced motility and severely reduced caffeine-induced hyperactivation compared to controls. Ability to penetrate the zona pellucida, cleavage rate, cleavage kinetics, and blastocyst yield after IVF or AI were significantly lower than in control bulls. Whole-genome sequencing from semen and RNA sequencing of testis tissue revealed a critical mutation in adenylate kinase 9 (AK9) that impaired splicing, leading to a premature termination codon and a severely truncated protein. Mice deficient in AK9 were generated to further investigate the function of the gene; knockout males were phenotypically indistinguishable from their wild-type littermates but produced immotile sperm that were incapable of normal fertilization. These sperm exhibited numerous abnormalities, including a low ATP concentration and reduced motility. RNA-seq analysis of their testis revealed differential gene expression of components of the axoneme and sperm flagellum as well as steroid metabolic processes. Sperm ultrastructural analysis showed a high percentage of sperm with abnormal flagella. Combined bovine and murine data indicate the essential metabolic role of AK9 in sperm motility and/or hyperactivation, which in turn affects sperm binding and penetration of the zona pellucida. Thus, AK9 has been found to be directly implicated in impaired male fertility in mammals.

SPAG17 mediates nuclear translocation of protamines during spermiogenesis.

Protamines (PRM1 and PRM2) are small, arginine-rich, nuclear proteins that replace histones in the final stages of spermiogenesis, ensuring chromatin compaction and nuclear remodeling. Defects in protamination lead to increased DNA fragmentation and reduced male fertility. Since efficient sperm production requires the translocation of protamines from the cytoplasm to the nucleus, we investigated whether SPAG17, a protein crucial for intracellular protein trafficking during spermiogenesis, participates in protamine transport. Initially, we assessed the protein-protein interaction between SPAG17 and protamines using proximity ligation assays, revealing a significant interaction originating in the cytoplasm and persisting within the nucleus. Subsequently, immunoprecipitation and mass spectrometry (IP/MS) assays validated this initial observation. Sperm and spermatids from Spag17 knockout mice exhibited abnormal protamination, as revealed by chromomycin A3 staining, suggesting defects in protamine content. However, no differences were observed in the expression of Prm1 and Prm2 mRNA or in protein levels between testes of wild-type and Spag17 knockout mice. Conversely, immunofluorescence studies conducted on isolated mouse spermatids unveiled reduced nuclear/cytoplasm ratios of protamines in Spag17 knockout spermatids compared to wild-type controls, implying transport defects of protamines into the spermatid nucleus. In alignment with these findings, in vitro experiments involving somatic cells, including mouse embryonic fibroblasts, exhibited compromised nuclear translocation of PRM1 and PRM2 in the absence of SPAG17. Collectively, our results present compelling evidence that SPAG17 facilitates the transport of protamines from the cytoplasm to the nucleus.

Morphometric assessment of cryopreserved livestock bull spermatozoa in the tropics.

The identification of different morphometric patterns of spermatozoa serves as a basis for improving our understanding of the diversity in an ejaculate and to relate them to the potential fertility of males. In this study, we aimed to examine the semen subpopulation structure, following dilution in semen of extenders, using a mathematical approach a possible application to fertility analyses. Ten sexually mature Bos taurus bulls were randomly allotted to one of three groups: (1) Tris-citric acid-egg yolk extender (Tris-EY); (2) commercial egg yolk extender OptiXcell® and (3) commercial egg yolk extender Triladyl®. The results showed significant differences (p < .05) between extenders in terms of values for head size and head shape variables of individual sperm, indicating an influence of extender composition. Sperm head width was found to significantly differ (p < .05) according to the extender, decreasing in the following order: OptiXcell® (4.836 ± 0.017 µm), Triladyl® (4.695 ± 0.012 µm) and Tris-EY (4.638 ± 0.010 µm). Principal component analysis allowed us to identify two subpopulations in OptiXcell®, and three subpopulations were each found in Triladyl® and Tris-EY. Overall, we observed significant differences between sperm subpopulations within each extender (p < .05), with differences in sperm head size and shape between bovine species that can be related to functionality and fertility capabilities.

Are There Differences between Methods Used for the Objective Estimation of Boar Sperm Concentration and Motility?

Artificial insemination in the swine industry, as in other species, demands adequate semen handling and accurate evaluation for the preparation of seminal doses. Sperm concentration and motility estimates are part of the semen evaluation process and are considered important for maximizing the yield of doses for insemination. In this study, methods were examined for their accuracy in the estimation of boar sperm concentration and motility. Assessments of sperm concentration were carried out using iSperm®, ISAS® v1, Open CASA v2, and the Accuread® photometer. Analyses of sperm motility were performed with iSperm®, ISAS® v1, and Open CASA v2 systems. In this study, boar semen samples were collected from 10 healthy males from two genetic lines. There were no relevant differences between sire lines when sperm concentration was assessed. A Bayesian analysis was applied to the four methods used to assess sperm concentration to examine whether there are relevant differences between them. Results suggested differences in the four methods, with a probability of relevance (PR) of 0.86-1.00. The iSperm® method revealed higher concentration values within the highest posterior density region at 95% confidence interval (HPD95%) = 167.0, 224.2 M/mL, whereas Open CASA v2 showed the lowest values, with HPD95% = 99.3, 155.9 M/mL. The iSperm® demonstrated higher reliability in measuring sperm concentration compared to other methods or devices within the given range of confidence. ANOVAs revealed relevant differences in the three methods of motility estimation. Overall, differences in boar sperm concentration and motility estimates were found using various methods, but further studies are needed for better characterization of these differences.

Effect of incubation and analysis temperatures on sperm kinematics and morphometrics during human semen analysis.

INTRODUCTION: Human semen analysis must be performed after the liquefaction of the ejaculate. This takes place about 30min after ejaculation and samples must be maintained in the lab during this time. The temperatures for this incubation and the final analysis of motility are crucial but seldom taken into account. This study aims to examine the effect of these temperatures on various sperm parameters both manually (sperm count, motility, morphology, viability, chromatin condensation and maturation and DNA fragmentation) and CASA (kinematics and morphometrics, using an ISAS®v1 CASA-Mot and CASA-Morph systems, respectively) analyzed. METHODS: Seminal samples from thirteen donors were incubated for 10min at 37°C followed by additional 20min at either room temperature (RT, 23°C) or 37°C and then examined following WHO 2010 criteria. RESULTS: The data obtained show that there were no significant differences (P>0.05) in the subjective sperm quality parameters with incubation temperature. On the other hand, the head sperm morphometric parameters were significantly higher after room temperature incubation showing, in addition, lower ellipticity (P<0.05). Furthermore, kinematic parameters were evaluated both at RT and 37°C for the two incubation temperatures. In general, the four temperature combinations showed that kinematic parameters followed this order: RT-RT

The Importance of Studying Factors That Affect the In Vitro Evaluation of Semen Quality to Predict Potential Fertility in Males.

The presence of sub-fertile or infertile males in farms or artificial insemination (AI) centres has a great impact on the reproductive and economic performance of the livestock industry [...].

Kinematic and Morphometric Assessment of Fresh Semen, before, during and after Mating Period in Brahman Bulls.

The objective of the present study was to determine the effects that the reproductive season has on the motility, kinematics, morphology, and sperm morphometry of Brahman bulls evaluated with a commercial CASA system. The experiment was carried out at the Costa Rica Institute of Technology from March to August 2021. A total of eight Brahman bulls were used. A total of 28 ejaculates were collected in the pre-mating period (PMP), during it (DMP), and after it (AMP) using an electroejaculator. The sperm concentration was measured with the Accuread photometer. The motility was measured using a Spermtrack® counting chamber. The analyses were performed with the CASA-Mot ISAS®v1 system. The morphology was analyzed using a microscope with a negative phase contrast objective. Morphometry was evaluated with the CASA-Morph. The sperm concentration did not present differences between the PMP and AMP; however, it was significantly higher than DMP (p > 0.05). Regarding the progressiveness variables, linearity on forward progression (LIN), straightness (STR), and wobble (WOB) were higher (p < 0.05) DMP. A kinematic principal component analysis grouped all the variables into three factors and an effect on the reproductive period was found (p < 0.05) in the parameters of the head and middle part of the sperm, such as width and perimeter, which were greater in the PMP. The length of the sperm head in the PMP and DMP did not show differences; however, both were larger (p < 0.05) than AMP. The insertion distance of the middle piece of the sperm was significantly greater than DMP. Finally, the PMP contained cells with a larger insertion angle (p < 0.05) than AMP. These findings are important to understand the implications of reproductive status on sperm quality and to consider them in andrological evaluations.

Effect of High Viscosity on Energy Metabolism and Kinematics of Spermatozoa from Three Mouse Species Incubated under Capacitating Conditions.

In order to sustain motility and prepare for fertilization, sperm require energy. The characterization of sperm ATP production and usage in mouse species revealed substantial differences in metabolic pathways that can be differentially affected by capacitation. Moreover, spermatozoa encounter different environments with varying viscoelastic properties in the female reproductive tract. Here, we examine whether viscosity affects sperm ATP levels and kinematics during capacitation in vitro. Sperm from three mouse species (Mus musculus, M. spretus, M. spicilegus) were incubated under capacitating conditions in a modified Tyrode's medium containing bicarbonate, glucose, pyruvate, lactate, and bovine serum albumin (mT-BH) or in a bicarbonate-free medium as a non-capacitating control. Viscosity was increased with the inclusion of polyvinylpyrrolidone. ATP was measured with a bioluminescence kit, and kinematics were examined with a computer-aided sperm analysis system. In M. musculus sperm, ATP declined during capacitation, but no differences were found between non-capacitating and capacitating sperm. In contrast, in M. spretus and M. spicilegus, ATP levels decreased in capacitating sperm. Increasing viscosity in the medium did not modify the timing or proportion of cells undergoing capacitation but did result in additional time- and concentration-dependent decreases in ATP in M. spretus and M. spicilegus under capacitating conditions. Additionally, increased viscosity altered both velocity and trajectory descriptors. The limited impact of capacitation and higher viscosity on M. musculus sperm ATP and kinematics could be related to the low intensity of postcopulatory sexual selection in this species. Responses seen in the other two species could be linked to the ability of their sperm to perform better under enhanced selective pressures.

Bioenergetic changes in response to sperm capacitation and two-way metabolic compensation in a new murine model.

The acquisition of fertilizing ability by mammalian spermatozoa, known as "capacitation," includes processes that depend on particular metabolic pathways. This has led to the hypothesis that ATP demands might differ between capacitated and non-capacitated cells. Mouse sperm can produce ATP via OXPHOS and aerobic glycolysis, an advantageous characteristic considering that these cells have to function in the complex and variable environment of the female reproductive tract. Nonetheless, despite evidence showing that both metabolic pathways play a role in events associated with mouse sperm capacitation, there is contradictory evidence regarding changes promoted by capacitation in this species. In addition, the vast majority of studies regarding murine sperm metabolism use Mus musculus laboratory strains as model, thus neglecting the wide diversity of sperm traits of other species of Mus. Focus on closely related species with distinct evolutionary histories, which may be the result of different selective pressures, could shed light on diversity of metabolic processes. Here, we analyzed variations in sperm bioenergetics associated with capacitation in spermatozoa of the steppe mouse, Mus spicilegus, a species with high sperm performance. Furthermore, we compared sperm metabolic traits of this species with similar traits previously characterized in M. musculus. We found that the metabolism of M. spicilegus sperm responded to capacitation in a manner similar to that of M. musculus sperm. However, M. spicilegus sperm showed distinct metabolic features, including the ability to perform cross-pathway metabolic compensation in response to either respiratory or glycolytic inhibition, thus revealing a delicate fine-tuning of its metabolic capacities.

Capacitation promotes a shift in energy metabolism in murine sperm.

In mammals, sperm acquire fertilization ability after a series of physiological and biochemical changes, collectively known as capacitation, that occur inside the female reproductive tract. In addition to other requirements, sperm bioenergetic metabolism has been identified as a fundamental component in the acquisition of capacitation. Mammalian sperm produce ATP through two main metabolic processes, oxidative phosphorylation (OXPHOS) and aerobic glycolysis that are localized to two different flagellar compartments, the midpiece, and the principal piece, respectively. In mouse sperm, the occurrence of many events associated with capacitation relies on the activity of these two energy-producing pathways, leading to the hypothesis that some of these events may impose changes in sperm energetic demands. In the present study, we used extracellular flux analysis to evaluate changes in glycolytic and respiratory parameters of murine sperm that occur as a consequence of capacitation. Furthermore, we examined whether these variations affect sperm ATP sustainability. Our results show that capacitation promotes a shift in the usage ratio of the two main metabolic pathways, from oxidative to glycolytic. However, this metabolic rewiring does not seem to affect the rate at which the sperm consume ATP. We conclude that the probable function of the metabolic switch is to increase the ATP supply in the distal flagellar regions, thus sustaining the energetic demands that arise from capacitation.

Influence of Fat-Soluble Vitamin Intramuscular Supplementation on Kinematic and Morphometric Sperm Parameters of Boar Ejaculates.

Ejaculate quality can be regarded as multifactorial, with nutrition being a factor that could directly influence sperm parameters. The present study aimed to evaluate seminal quality associated with seasonal fat-soluble vitamin supplementation of boars. Seven sexually mature boars were randomly allotted to one of the three groups, and fed one of the three supplementary diets for 32 weeks: (1) control treatment (COD), without supplementation of fat-soluble vitamins, (2) treatment containing 100% fat-soluble vitamin supplementation administered intramuscularly, which was based on fat soluble vitamin supplementation (A, D3, E) (FVD1), and (3) treatment containing 50% of fat-soluble vitamin supplementation (FVD 1 2 ). Semen was collected at 7-day intervals. Semen samples were analyzed to assess several sperm parameters using the Computer-Assisted Semen Analysis (CASA) ISAS®v1 system. Results showed that groups receiving FVD1 and FVD 1 2 supplementation had an increased semen volume. The percentages of motile and progressively motile sperm were increased by FVD1 treatment. A statistically significant interaction between treatment and season was found in the percentage of motility and progressive motility (p < 0.05). Sperm concentrations showed significant differences (p < 0.05) between treatments. Velocity variables (VSL, VCL, and VAP) were higher (p < 0.05) in boars that received fat-soluble vitamin supplementation in comparison to controls receiving no supplementation. The FVD1 treatment presented spermatozoa with greater head size and more elongated heads (p < 0.05). Overall, the utilization of dietary fat-soluble vitamin supplementation significantly improved the semen quality of boar ejaculates. This highlights the importance of fat-soluble vitamin supplementation in sexually active boars.

Effect of Motility Factors D-Penicillamine, Hypotaurine and Epinephrine on the Performance of Spermatozoa from Five Hamster Species.

Assessments of sperm performance are valuable tools for the analysis of sperm fertilizing potential and to understand determinants of male fertility. Hamster species constitute important animal models because they produce sperm cells in high quantities and of high quality. Sexual selection over evolutionary time in these species seems to have resulted in the largest mammalian spermatozoa, and high swimming and bioenergetic performances. Earlier studies showed that golden hamster sperm requires motility factors such as D-penicillamine, hypotaurine and epinephrine (PHE) to sustain survival over time, but it is unknown how they affect swimming kinetics or ATP levels and if other hamster species also require them. The objective of the present study was to examine the effect of PHE on spermatozoa of five hamster species (Mesocricetus auratus, Cricetulus griseus, Phodopus campbelli, P. sungorus, P. roborovskii). In sperm incubated for up to 4 h without or with PHE, we assessed motility, viability, acrosome integrity, sperm velocity and trajectory, and ATP content. The results showed differences in the effect of PHE among species. They had a significant positive effect on the maintenance of sperm quality in M. auratus and C. griseus, whereas there was no consistent effect on spermatozoa of the Phodopus species. Differences between species may be the result of varying underlying regulatory mechanisms of sperm performance and may be important to understand how they relate to successful fertilization.

Energy Metabolism and Hyperactivation of Spermatozoa from Three Mouse Species under Capacitating Conditions.

Mammalian sperm differ widely in sperm morphology, and several explanations have been presented to account for this diversity. Less is known about variation in sperm physiology and cellular processes that can give sperm cells an advantage when competing to fertilize oocytes. Capacitation of spermatozoa, a process essential for mammalian fertilization, correlates with changes in motility that result in a characteristic swimming pattern known as hyperactivation. Previous studies revealed that sperm motility and velocity depend on the amount of ATP available and, therefore, changes in sperm movement occurring during capacitation and hyperactivation may involve changes in sperm bioenergetics. Here, we examine differences in ATP levels of sperm from three mouse species (genus Mus), differing in sperm competition levels, incubated under non-capacitating and capacitating conditions, to analyse relationships between energetics, capacitation, and swimming patterns. We found that, in general terms, the amount of sperm ATP decreased more rapidly under capacitating conditions. This descent was related to the development of a hyperactivated pattern of movement in two species (M. musculus and M. spicilegus) but not in the other (M. spretus), suggesting that, in the latter, temporal dynamics and energetic demands of capacitation and hyperactivation may be decoupled or that the hyperactivation pattern differs. The decrease in ATP levels during capacitation was steeper in species with higher levels of sperm competition than in those with lower levels. Our results suggest that, during capacitation, sperm consume more ATP than under non-capacitating conditions. This higher ATP consumption may be linked to higher velocity and lateral head displacement, which are associated with hyperactivated motility.