Resveratrol prevents capacitation-like changes and improves in vitro fertilizing capability of buffalo frozen-thawed sperm

Incorporating olive (Olea europaea L) fruit extracts in a tris-based extender improves buffalo semen cryotolerance by reducing oxidative stress

This work aimed to evaluate whether supplementing the freezing extender with olive fruit extract (OFE) would improve the antioxidant defense of buffalo sperm, resulting in improved post-thaw semen quality. Ejaculates (two per 16 Murrah buffalo bulls) were split into four aliquots that were diluted in an extender supplemented with different doses of OFE (0, D50, D100, and D150, based on µM concentrations of hydroxytyrosol, the most represented polyphenol) and frozen according to standard procedures. At thawing, sperm motility, kinetics, viability, acrosome integrity, and membrane functionality were evaluated. Based on the dose-response results, biological antioxidant potential (BAP) and reactive oxygen metabolites (ROMs) were assessed after thawing in D50 and control groups. The pre-freezing supplementation of the extender with D50 OFE showed higher (P < 0.05) total and progressive sperm motility, as well as straight-line velocity compared to the control. Treatment with D50 OFE of buffalo semen also improved (P < 0.01) post-thaw sperm viability, membrane functionality, and acrosome integrity compared to the control. The enrichment of the extender with D50 OFE increased (P < 0.01) the post-thaw BAP and reduced (P < 0.05) the ROMs levels. The highest concentration tested (D150 OFE) negatively affected (P < 0.05) total and progressive motility, and the percentage of sperm with functional membranes and intact acrosomes, compared to the control. In conclusion, low doses of OFE added to the extender significantly improved post-thawing buffalo semen quality by protecting the spermatozoa from cryopreservation-induced oxidative stress. Further studies should investigate its effectiveness on in vivo and in vitro fertility, for potential commercial applications.

Effect of resveratrol on post-thaw motility, kinematics, structural parameters and antioxidant/oxidant status of Kamori buck spermatozoa

Resveratrol is a polyphenol compound showing strong antioxidant properties. It is believed that semen cryopreservation causes significant sperm losses which eventually affects sperm quality. Improving antioxidant status of semen may reduce this damage and enhance sperm fertilizing potential. This study investigated the resveratrol treated freeze-thawing sperm motion, kinetics, structural parameters and antioxidant/oxidant status of Kamori buck spermatozoa. Thirty-two ejaculates from 4 fertile Kamori bucks were processed in tris-citric-glyercol-egg yolk (TCG-EY) based with varying concentrations of resveratrol (0, 10, 20, 40 and 50 μM). Over 75 % sperm motility were pooled and frozen in liquid nitrogen. The results unveiled that adding resveratrol at 40 and 50 μM concentration significantly enhanced (P < 0.05) total motility (progressive motility, rapid velocity, and average path velocity, straight line velocity, curvilinear velocity, amplitude of lateral head displacement, beat cross frequency, straightness and linearity in contrast with control and other groups. Supplementing resveratrol at 40 and 50 μM concentration significantly improved (P < 0.05) functional plasma membrane integrity, acrosome integrity, whereas, all resveratrol groups had same significant (P < 0.05) effect on DNA integrity in response to control group. The 40 and 50 μM resveratrol significantly promoted (P < 0.05) superoxide dismutase (SOD), catalase (CAT), peroxidases (POD), and total antioxidant capacity (TAC) levels while significantly reducing (P < 0.05) the total oxidant status (TOS) and malondialdehyde (MDA) contents as compared to control and other groups, respectively. The principal component analysis (PCA) exhibited samples were present in different clusters except two groups which had partially overlapped. Using hierarchical clustering analysis, two clusters were constructed showing the relationship within the treated groups. The results of spearman correlation coefficient showed that yellow color showed highly positive correlation while turquoise color exhibited highly negative association between sperm variables. Overall, the results concluded that resveratrol at 50 μM performed slightly better results than 40 μM in terms of improving sperm quality parameters.

Resveratrol and antifreeze protein type I show no synergistic benefits in cryopreserved ram sperm

This study investigated the effect of resveratrol (RV) after thawing of ram sperm cryopreserved with or without the addition of antifreeze protein I (AFPI) on sperm quality during the 3 h incubation period. Each ram ejaculate was split into two aliquots, diluted in a TRIS egg yolk (TEY) extender supplemented with 0 (control) or 0.1 µg/mL AFPI, and then cooled and frozen. Thawed samples of both treatments were subdivided and incubated in Talp-Hepes medium with 0 (TEY and AFPI group) or 50 µM of RV (TEY + RV group and AFPI + RV group) for 3 h at 38 ºC. The sperm kinetics, capacitation status, plasma membrane integrity, mitochondrial activity, sperm-egg binding assay, and TBARS concentrations were evaluated at different intervals. Data were analyzed by mixed model, including the incubation time, AFP treatment, RV treatment, and their interactions as main effects, and the day of semen collection and the ram as random effects (P < 0.05; LS mean ± pooled SEM). The AFPI, RV treatments, and their interaction did not affect the average total motility (~ 17.1 ± 2.4%), progressive motility (~ 5.6 ± 1.4%), mitochondrial activity (~ 35.5 ± 2.3 arbitrary unit), plasma membrane integrity (~ 18.2 ± 2.4%), sperm binding capacity (~ 2.2 ± 0.1 sperm per mm2), TBARS concentrations (~ 1488.7 ± 27.4 ng/mL) and rates of capacitated (~ 27.5 ± 1.6%), non-capacitated (~ 20.9 ± 1.6%) and acrosome-reacted (~ 56.5 ± 4.1%) sperm. It was concluded that adding 0.1 µg/mL AFPI to the extender used for ram semen cryopreservation and/or further in vitro culture exposure to 50 µM RV did not improve in vitro sperm quality.

Proteomics and metabolomics analyses of mechanism underlying bovine sperm cryoinjury

BACKGROUND

The cryoinjury of semen during cryopreservation reduces sperm motility, constraining the application of artificial insemination (AI) in bovine reproduction. Some fertility markers, related to sperm motility before and after freezing have been identified. However, little is known about the biological mechanism through which freezing reduces sperm motility. This study investigated the selective effects of cryoinjury on high-motility sperm (HMS) and low-motility sperm (LMS) in frozen-thawed from the perspectives of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP levels. The molecular mechanism of decreased sperm motility caused by cryoinjury was explored through a joint analysis of 4D-label free quantitative proteomics and non-targeted metabolomics.

RESULTS

The results indicate that low levels of ROS and high degrees of MMP and ATP play a critical role in the survival of HMS during the freezing process. The sperm samples from the frozen-thawed HMS and LMS were analysed for proteomics and metabolomics, 2,465 proteins and 4,135 metabolites were detected in bovine sperm samples. In contrast to LMS, HMS have 106 proteins and 106 metabolites with high abundance expression, and 79 proteins and 223 metabolites with low abundance expression. Proteomics and metabolomics data exhibit that highly expressed antioxidant enzymes and metabolites in HMS can maintain sperm motility by regulating the ROS produced during freezing to prevent sperm from oxidative stress and apoptosis. Furthermore, the KEGG analysis of differential proteins and metabolites during the freezing process implies that the significant enrichment of glycolysis and cAMP in HMS can guarantee energy supply.

CONCLUSIONS

The results provided that during the process of bovine sperm freezing, highly expressed antioxidant enzymes can regulate the reactive oxygen species levels to avoid oxidative stress and the glycolysis signalling pathway ensures ATP production can sustain frozen-thawed sperm motility.

Polyphenols as a strategy for improving male reproductive system

Reproduction in males is one of the complicated processes that is mediated by many environmental factors, as well as by diet (e.g. supplements, nutritional value). The parameters of reproduction like sperm cells, hormones and testicular histology are highly prone to oxidative stress due to influence of factors on reproductive processes. Polyphenols are naturally present in feed of animals as shrubs, trees and agro-industrial by products. The exposures of these polyphenols through diet have strong antioxidants properties. However, the benefits of these substances on reproductive health are not always certain. The use of these polyphenols in the diet of animals and in the semen extender has been reported as remarkable benefits. These beneficial effects are manifested in the form of improvement of antioxidant potential via the reduction in the production of reactive oxygen species. Polyphenols are also used for cryopreservation of various species for the genetic improvement of various species. This review gathers all the findings related to dietary consumptions of polyphenols on reproductive performance of male of various species as well as use in semen extender in fresh and frozen semen.

The Effect of Cholesterol-Loaded Cyclodextrin and Resveratrol Compounds on Post-Thawing Quality of Ram Semen

Ram sperm are more vulnerable to freezing than those of most other farm animals. During sperm freezing, the cell membrane loses some of its cholesterol, which regulates signalling mechanisms and prevents premature capacitation. Resveratrol (RES) increases the fluidity of the cell membrane, which becomes peroxidized during freezing and reduces free radicals. In this study, the effectiveness of RES, cholesterol-loaded cyclodextrin (CLC) and their combinations in ram sperm cryopreservation were investigated. The collected semen was divided into two equal volumes: One was diluted with tris-citric acid-glucose medium (TCG) containing CLC, whereas the other was diluted with a CLC-free TCG solution. After examining motility, both groups were further divided into two equal volumes, forming the following working groups: control (no RES, no CLC); RES (20 µg/mL); CLC (2 mg CLC/120 × 106 sperm); and RES + CLC (RES 20 µg/mL + 2 mg CLC/120 × 106 sperm). These groups were diluted with media containing their respective additives. Post-thawing, the samples were analysed for motility, acrosome and membrane integrity, membrane functionality, mitochondrial activity, capacitation status, oxidative stress and DNA integrity. CLC preserved sperm total motility, acrosome and plasma membrane integrity and decreased the rate of early capacitation (p < 0.05). RES had no significant effect on sperm quality before freezing and post-thawing (p > 0.05). However, RES + CLC increased mitochondrial activity post-thawing (p < 0.05). In conclusion, CLC minimized sperm membrane damage caused by cryopreservation in ram sperm. RES alone was ineffective, and the combination of RES and CLC did not yield a positive synergistic effect on ram spermatological parameters.

Incubating frozen-thawed buffalo sperm with olive fruit extracts counteracts thawing-induced oxidative stress and improves semen quality

Freezing-thawing procedures and semen manipulation for in vitro fertilization induce oxidative stress, which in turn leads to impaired sperm quality. The aim of this study was to evaluate whether incubation of frozen-thawed buffalo semen with olive fruit extracts (OFE), known to contain a high concentration of phenolic antioxidants, would improve semen quality by reducing oxidative stress. Frozen sperm (4 ejaculates/4 bulls/3 replicates) were thawed and diluted to 30 × 106/mL in IVF medium with 0, 72, 143, and 214 μL/mL of OFE, corresponding to 0 (D0-control), 50 (D50), 100 (D100), and 150 (D150) μM hydroxytyrosol. Sperm viability, acrosome integrity, membrane functionality, motility, and sperm kinetics were evaluated immediately after thawing (T0) and after 1 (T1) and 2 h (T2) of incubation at 38.7 °C. Based on the results, sperm biological antioxidant potential (BAP) and ROS levels (ROMs) were assessed in D0 and D100 groups at T1 and T2. To assess the effect of OFE on fertilizing ability, heterologous penetration rates were also evaluated, using bovine abattoir-derived oocytes. The treatment with OFE at all concentrations tested increased (P < 0.05) the percentage of acrosome intact spermatozoa compared to the D0-control at T1, but the effect was more evident (P < 0.01) with D100 (54.5 ± 3.0, 60.5 ± 1.5, 65.2 ± 3.3, and 62.5 ± 1.7, with D0, D50, D100, and D150 OFE, respectively). Total motility, progressive motility, rapid velocity, and progressive velocity decreased (P < 0.05) at T2 only in the D0-control group. The percentage of rapidly progressive sperm and the progressive motility tended to increase (P < 0.10) at T1 and T2, respectively, in D100 compared to D0 (24.7 ± 4.1 vs 16.4 ± 1.6 and 22.8 ± 2.7 vs 17.0 ± 1.2, respectively). The treatment with D100 OFE of frozen-thawed sperm increased (P < 0.05) some kinetic parameters (VAP and WOB). Spermatozoa incubated with D100 OFE exhibited higher (P < 0.01) total and normospermic oocyte penetration rates compared to D0 (86.5 ± 1.4 vs 78.5 ± 0.7, and 70.6 ± 1.5 vs 63.8 ± 1.1, respectively). Additionally, D100 OFE increased sperm BAP concentrations at both T1 and T2, while ROS levels were unaffected. These results suggest that incubating frozen-thawed buffalo semen with OFE is an effective strategy for preserving semen quality and in vitro fertilization ability by enhancing sperm antioxidant capacity.

Cryoprotective Potential of Theobromine in the Improvement of the Post-Thaw Quality of Bovine Spermatozoa

Theobromine (TBR) is a methylxanthine known for its bronchodilatory and stimulatory effects. This research evaluated the vitality, capacitation patterns, oxidative characteristics, microbial profile and expression of capacitation-associated proteins (CatSper1/2, sodium bicarbonate cotransporter [NBC], protein kinases A [PKA] and C [PKC] and adenylate cyclase 10 [ADCY10]) in cryopreserved bovine spermatozoa (n = 30) in the absence (cryopreserved control [CtrlC]) or presence of different TBR concentrations (12.5, 25, and 50 µM) in egg yolk extender. Fresh ejaculate served as a negative control (CtrlN). Significant post-thaw maintenance of the sperm motility, membrane and DNA integrity and mitochondrial activity (p < 0.001) were recorded following the administration of 25 μM and 50 μM TBR, then compared to CtrlC. All groups supplemented with TBR exhibited a significantly lower percentage of prematurely capacitated spermatozoa (p < 0.001) than CtrlC. Significantly decreased levels of global reactive oxygen species (ROS), hydrogen peroxide and hydroxyl radicals were observed in the presence of 25 μM and 50 μM TBR (p < 0.01). Western blot analysis revealed that supplementation with 50 μM TBR significantly prevented the loss of NBC and ADCY10 (p < 0.01), while all TBR doses stabilized the levels of PKC (p < 0.05 at 50 μM TBR; p < 0.001 at 12.5 μM and 25 μM TBR). In summary, we suggest that TBR is effective in protecting the spermatozoa during the cryopreservation process through its potential to stimulate energy synthesis while preventing ROS overproduction and the loss of proteins involved in the sperm activation process.

Effects of Supplementation of Different Antioxidants to Cryopreservation Extender on the Post-Thaw Quality of Rooster Semen-A Meta-Analysis

The standardization of the semen cryopreservation technique could be an effective tool in poultry for the conservation of genetic resources. During this process, the production of reactive oxygen species increases, leading to oxidative stress that causes damage to the spermatozoa. To reduce this effect, the addition of exogenous antioxidants in the cryopreservation diluent has been reported to be effective. Multiple antioxidants such as catalase, vitamin E, cysteamine, ergothioneine, and serine have been studied in roosters. Therefore, the present investigation aims to perform a meta-analysis to determine if the use of the aforementioned antioxidants added to the cryopreservation extender produces an improvement in semen quality parameters in roosters after thawing. After collecting the data, a discriminant canonical analysis was performed to determine which of the selected semen quality traits provided the most information, with hypo-osmotic swelling test (HOST), viability, and total motility variables showing the highest discriminatory power. However, according to the descriptive statistics, catalase and serine are the antioxidants that improve a greater number of seminal quality parameters, and since catalase gives the most favorable results for most of the discriminating variables, it could be the antioxidant of choice.

Effects of Resveratrol-Loaded Cyclodextrin on the Quality Characteristics of Ram Spermatozoa Following Cryopreservation

This study investigated the effects of pure and methyl-β-cyclodextrin loaded forms of resveratrol (10 µg/mL, 20 µg/mL, and 40 µg/mL) on ram sperm functions post-thawing. Semen samples were pooled and divided into ten groups: Control, RES10, RES20, RES40, CD10, CD20, CD40, RLC10, RLC20, and RLC40. The groups were pre-diluted with media containing the group-specific chemicals, followed by 15 min of incubation, dilution, and freezing. To assess the effects of the chemicals, a post-thaw sperm quality assessment was conducted. Motility and other velocity parameters were evaluated using computer-assisted semen analysis. The functional integrity of spermatozoa membranes was assessed with the hypo-osmotic swelling test, and the capacitation status of spermatozoa was determined through fluorescent microscopic evaluation. Additionally, flow cytometry was used to evaluate mitochondrial activity, oxidative stress, and the integrity of the sperm membrane and acrosome. The results indicated that cyclodextrin adversely affected sperm functions following freezing-thawing, notably increasing the rate of spermatozoa exhibiting pre-capacitation and mitochondrial activity by approximately 34% and 16%, respectively (p < 0.05). It was found that 20 µg/mL resveratrol prevented pre-capacitation (p < 0.05). Both resveratrol and resveratrol-loaded cyclodextrin groups improved post-thaw sperm qualities overall, demonstrating their utility for freezing ram semen. However, higher concentrations of resveratrol were found to negatively impact sperm functions.

Clinical Modalities for Enhancing Reproductive Efficiency in Buffaloes: A Review and Practical Aspects for Veterinary Practitioners

This review aimed to bring a comprehensive analysis of key clinical strategies for enhancing reproductive efficiency in buffaloes, a species that exhibit low reproductive performance under conventional reproductive management compared to that exhibited by cattle. It considers key ART techniques including estrus synchronization for artificial insemination, and ovulation induction, highlighting their role in improving fertility and overall herd productivity. However, it also addresses common postpartum inflammatory and functional reproductive disorders, discussing their diagnosis and treatment protocols, stressing their impact on the overall reproductive outcome in buffalo farming.

The influence of rutin and chlorogenic acid on oxidative stress and in vivo fertility: Evaluation of the quality and antioxidant status of post-thaw semen from Azari water buffalo bulls

BACKGROUND

The vulnerability of buffalo sperm to cryoinjury necessitates the improvement of sperm cryo-resistance as a critical strategy for the widespread use of assisted reproductive technologies in buffalo.

OBJECTIVES

The main aim of the present study was to evaluate the effects of different concentrations of rutin and chlorogenic acid (CGA) on buffalo semen quality, antioxidant activity and fertility during cryopreservation.

METHODS

The semen was collected and pooled from the 3 buffaloes using an artificial vagina (18 ejaculations). The pooled sperm were divided into nine different groups: control (Tris-based extender); 0.4, 0.6, 0.8 and 1 mM rutin (rutin + Tris-based extender); and 50, 100, 150 and 200 µM CGG (CGA + Tris-based extender). Sperm kinematics, viability, hypo-osmotic swelling test, mitochondrial activity, antioxidant activities and malondialdehyde (MDA) concentration of frozen and thawed buffalo sperm were evaluated. In addition, 48 buffalo were finally inseminated, and pregnancy was rectally determined 1 month after insemination.

RESULTS

Compared to the control group, adding R-0.4, R-0.6, CGA-100 and CGA-150 can improve total and progressive motility, motility characteristics, viability, PMF and DNA damage in buffalo sperm. In addition, the results showed that R-0.4, R-0.6, CGA-50, CGA-100 and CGA-150 increased total antioxidant capacity, catalase, glutathione peroxidase and glutathione activities and decreased MDA levels compared to the control group. Furthermore, it has been shown that adding 150 µM CGA and 0.6 mM rutin to an extender can increase in vivo fertility compared to the control group.

CONCLUSIONS

In conclusion, adding rutin and CGA to the extender improves membrane stability and in vivo fertility of buffalo sperm by reducing oxidative stress.

Effect of Codonopsis pilosula polysaccharide on the quality of sheep semen preservation at 4°C

OBJECTIVE

This study aimed to investigate the effect of Codonopsis pilosula polysaccharide (CPP) on the motility, mitochondrial integrity, acrosome integrity rate, and antioxidant ability of sheep sperm after preservation at 4°C.

METHODS

Semen from healthy adult rams were collected and divided into four groups with separate addition of 0, 200, 400, and 1,000 mg/L CPP. Sperm motility was analyzed using the Computer-Assisted Semen Analysis software after preservation at 4°C for 24, 72, 120, and 168 h. Sperm acrosome integrity rate was analyzed by Giemsa staining at 24, 72, and 120 h, and mitochondrial membrane integrity was analyzed by Mito-Tracker Red CMXRos. The total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content of spermatozoa were measured after 120 h of preservation.

RESULTS

The sperm viability and forward-moving sperm under 200 mg/L CPP were significantly higher than that in the control group at 72 h (61.28%±3.89% vs 52.83%± 0.70%, 51.53%±4.06% vs 42.84%±1.14%), and 168 h (47.21%±0.85% vs 41.43%±0.37%, 38.68%±0.87% vs 31.68%±0.89%). The percentage of fast-moving sperm (15.03%±1.10% vs 11.39%±1.03%) and slow-moving sperm (23.63%±0.76% vs 20.29%±1.11%) in the 200 mg/L group was significantly higher than control group at 168 h. The mitochondrial membrane integrity of the sperm in the group with 200 mg/L CPP was significantly higher than those in the control group after storage at 4°C for 120 h (74.76%±2.54% vs 65.67% ±4.51%, p<0.05). The acrosome integrity rate in the group with 200 mg/L (87.66%±1.26%) and 400 mg/L (84.00%±2.95%) was significantly higher than those in the control group (80.65%±0.16%) after storage for 24 h (p<0.05). CPP also increased T-AOC and decreased the MDA concentration after preservation at 4°C (p<0.05).

CONCLUSION

Adding CPP could improve the T-AOC of sperm, inhibit lipid peroxidation, and facilitate semen preservation.

Effects of meteorology and lunar cycle on the post-thawing quality of avian sperm

Introduction

Various climatological and lunar cycle parameters have a direct impact on animal reproduction, and in the case of the avian species, spermatozoa are extremely sensitive to heat stress. These parameters could influence sperm freezability, which will ultimately affect post-thawing semen quality, being sperm motility in roosters a relevant indicator of this quality as it is highly related to fertility. Therefore, the objective of the present study is to determine which are the climatological and lunar cycle parameters that have a greater effect on sperm freezability in roosters.

Methods

Sperm was obtained from 16 Utrerana breed roosters and a total of 27 replicates were performed. A pool was made with those ejaculates that met the minimum quality criteria for each replicate, and four freezing-thawing samples per replicate were analyzed. The straws were thawed, and sperm motility was evaluated, classifying the results obtained into four seminal quality groups according to the guidelines of the Food and Agriculture Organization of the United Nations (Group 1: Good, Group 2: Satisfactory, Group 3: Acceptable but undesirable and Group 4: Unsatisfactory). The following traits were recorded for each day of semen collection: maximum temperature, minimum temperature, maximum barometric pressure, minimum barometric pressure, maximum gust, wind direction, mean wind speed, sunshine hours, rainfall, moon phase, and percentage of illuminated lunar surface over the total area.

Results

A discriminant canonical analysis was performed to determine which of these parameters offered the most information when classifying an ejaculate in each quality group, with minimum temperature, the new moon as moon phase, minimum barometric pressure, and rainfall being the most significant variables.

Discussion

According to the results obtained, semen quality decreases when temperature and precipitation are lower, pressure is higher, and when there is a new moon phase. Therefore, these environmental conditions should be avoided for sperm collection and processing.

Effects of resveratrol on DLD and NDUFB9 decrease in frozen semen of Mongolian sheep

Mongolian sheep are a breed of sheep in China known for their excellent cold and drought resistance. Sperm from Mongolian sheep are often cryopreserved to improve breeding outcomes. However, cryopreservation of sperm often results in issues such as reduced vitality and altered morphology. Therefore, the objective of this study was to investigate the impact of the cryoprotectant resveratrol on frozen sperm from Mongolian sheep, specifically examining its effects on key proteins during cryopreservation. In this study, sperm samples were obtained from three adult Mongolian rams and processed through semen centrifugation. The sperm motility parameters of Fresh Sperm Group (FR), Resveratrol added before freezing group (FF-Res), Resveratrol-free frozen sperm group (FT), and Resveratrol added after freeze-thawing group (FA-Res) were determined. The tandem mass tags (TMT) peptide labeling combined with LC-MS/MS was used for proteomic analysis of the total proteins in FR and FT groups. A total of 2651 proteins were identified, among which 41 proteins were upregulated and 48 proteins were downregulated after freezing. In-depth bioinformatics analysis of differentially abundant proteins (DAPs) revealed their close association with the tricarboxylic acid cycle (TCA) and oxidative phosphorylation pathway. The energy-related protein dihydrolipoamide dehydrogenase (DLD) and the reactive oxygen species (ROS)-related protein NADH dehydrogenase 1 beta subcomplex subunit 9 (NDUFB9) exhibited significant decreases, indicating their potential role as key proteins contributing to reduced sperm vitality. The study demonstrated that the addition of resveratrol (RES) to semen could elevate the expression levels of DLD and NDUFB9 proteins. This study represents the pioneering proteomic analysis of Mongolian ram sperm before and after cryopreservation, establishing the significance of DLD and NDUFB9 as key proteins influencing the decline in vitality following cryopreservation of Mongolian ram sperm. These findings clarify that resveratrol can enhance the levels of DLD and NDUFB9 proteins in cryopreserved Mongolian ram sperm, consequently enhancing their vitality.

The association of resveratrol and AFPI did not enhance the cryoresistance of ram sperm

Cryoprotectants are required to reduce damage caused to the cells due to low temperatures during the cryopreservation. Antifreeze proteins (AFP) have a well-known role in cell membrane protection, while resveratrol is a potent antioxidant. This study assessed the effect of the association of resveratrol concentrations and AFP I in a ram semen extender. Pooled semen of four rams was allocated into six treatments in a factorial arrangement: (CONT, only the semen extender); only AFP I (ANT: 0.1 µg/mL of AFP I), only resveratrol, one treatment with two levels (10 µM/mL or 50 µM/mL of resveratrol); and two treatments with the interactions, with one AFP I and one of the two levels of resveratrol (0.1 µg/mL of AFP I with 10 µM/mL resveratrol; 0.1 µg/mL of AFP I with 50 µM/mL resveratrol). No interaction between factors was observed on sperm kinetics, plasma membrane integrity, hypo-osmotic test, and mitochondrial activity parameters. There was a high probability (P = 0.06) of reducing sperm cells with functional membrane percentage in the hypo-osmotic test and increasing the percentage of sperm with high mitochondrial activity (P = 0.07) was observed in AFP presence. An interaction of AFP and resveratrol was observed in non-capacitated sperm (P = 0.009), acrosomal reaction (P = 0.034), and sperm binding (P = 0.04). In conclusion, the association of resveratrol and AFP did not improve the quality of frozen-thawed semen and even promoted deleterious effects compared to their single addition in the semen extender. The supplementation of 50 µM/mL of resveratrol improved the outcomes of frozen-thawed ram sperm, being a potential cryoprotectant.

Quality and redox state of bovine sperm cryopreserved with resveratrol use of resveratrol in bovine semen

The use of antioxidants for semen preservation prevents oxidative damage caused by reactive oxygen species (ROS). One of the most promising natural antioxidants is resveratrol, a phytoalexin derived from plants, grapes, berries, peanuts and red wine. To evaluate the effect of resveratrol on the quality and redox status of cryopreserved bovine semen. Five bulls were subjected to electroejaculation to obtain 15 ejaculates. Each ejaculate was extended with a tris-egg yolk-glycerol-based medium and divided into six aliquots supplemented with 0 (control), 10, 20, 30, 40 and 50 μM of resveratrol. Semen was frozen with liquid nitrogen vapours. Post-thawing, motility and kinetics were evaluated using a computer-assisted sperm analysis (CASA) system, membrane integrity using the hypoosmotic test (HOST), morphology by staining with eosin-nigrosin, sperm vitality by fluorescence microscopy with the SYBR14/IP probes. Total antioxidant capacity (TAC) was evaluated using the ABTS•+ assay and ROS was evaluated using spectrofluorimetry with the H2 DCFDA probe. For the statistical analysis linear models were adjusted and means were compared using the Tukey test. All concentrations of resveratrol reduced post-thawed motility and kinetics of sperm. Supplementation with 40 and 50 μM of resveratrol reduced sperm kinetics, and between 30 and 50 μM of resveratrol alterations in the sperm membrane and morphology were observed. However, using resveratrol at 50 μM increased TAC and at 20 μM, it reduced ROS production of cryopreserved bovine semen. Resveratrol appears to have a dose-dependent effect in which higher doses produce greater sperm alterations, however, it can increase semen TAC during freezing. It is concluded that resveratrol can increase antioxidant capacity and reduce ROS production in cryopreserved bovine semen. However, its use between 10 and 50 μM reduces post-thawing semen quality.

Resveratrol Improves the Frozen-Thawed Ram Sperm Quality

Cryopreservation generates a substantial quantity of ROS in semen, leading to a decline in sperm quality and fertilization capacity. The objective of this study was to investigate the effects of resveratrol and its optimal concentration on ram sperm quality after cryopreservation. Ram semen was diluted with a freezing medium containing different concentrations of resveratrol (0, 25, 50, 75, and 100 μM). After thawing, various sperm parameters such as total motility, progressive motility, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, glutathione (GSH) content, glutathione synthase (GPx) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity, lipid peroxidation (LPO) content, malondialdehyde (MDA) content, ROS level, SIRT1 level, DNA oxidative damage, and AMPK phosphorylation level were assessed. In addition, post-thaw sperm apoptosis was evaluated. Comparatively, the addition of resveratrol up to 75 μM significantly improved the sperm motility and sperm parameters of cryopreserved ram sperm. Specifically, 50 μM resveratrol demonstrated a notable enhancement in acrosome and plasma membrane integrity, antioxidant capacity, mitochondrial membrane potential, adenosine triphosphate (ATP) content, SIRT1 level, and AMPK phosphorylation levels compared to the control group (p < 0.05). It also significantly (p < 0.05) reduced the oxidative damage to sperm DNA. However, detrimental effects of resveratrol were observed at a concentration of 100 μM resveratrol. In conclusion, the addition of 50 μM resveratrol to the cryopreservation solution is optimal for enhancing the quality of cryopreserved ram sperm.

Carboxylated Poly-L-lysine Potentially Reduces Human Sperm DNA Fragmentation after Freeze-Thawing, and Its Function Is Enhanced by Low-Dose Resveratrol

Sperm DNA fragmentation (SDF) that occurs during the freezing-thawing of sperm may negatively impact the treatment outcomes of assisted reproductive technologies (ART). In a previous study, we developed a human sperm cryopreservation reagent containing carboxylated poly-L-lysine (CPLL) that reduced SDF after freeze-thawing compared with clinically popular cryopreservation reagents containing human serum albumin. However, it is unclear whether CPLL reduces SDF, as it differed from the constituents of the commercial cryopreservation reagents used for comparison. Therefore, here, we examined whether CPLL reduces the SDF of human sperm and evaluated reactive oxygen species (ROS) levels and lipid peroxidation (LPO), which are the causes of SDF; mitochondrial injury, ROS production; and impaired sperm motility. Furthermore, optimal antioxidants and their concentrations that could further enhance the reduction in SDF were determined for future clinical application in ART and underwent the same functional evaluations. CPLL can reduce SDF via inhibition of intracytoplasmic ROS and LPO. Furthermore, the addition of 0.1 mM resveratrol avoided the enhancement of SDF, which potentially affects mitochondrial and cytoplasmic ROS and LPO. This novel human sperm cryopreservation reagent containing CPLL and resveratrol has the potential to improve treatment outcomes in ART using frozen sperm.

Discriminant Analysis and Data Mining CHAID Decision Tree as Tools to Evaluate the Buffering Effect of Hydroxytyrosol on Reactive Oxygen Species in Rooster Sperm Cryopreservation

Sperm cryopreservation is effective in safeguarding genetic biodiversity in avian species. However, during this process, spermatozoa are very susceptible to plasma membrane peroxidation in the presence of high concentrations of reactive oxygen species (ROS). To mitigate this effect, the addition of exogenous antioxidants, such as hydroxytyrosol (3,4-dihydroxyphenylethanol; HT), an antioxidant derived from olive oil, to the cryopreservation sperm diluent, could be useful. To verify this, a cryopreservation diluent was supplemented with different concentrations (0 μg/mL, 50 μg/mL, 100 μg/mL, and 150 μg/mL) of HT. For this, semen was collected in 10 replicates from 16 roosters of the Utrerana avian breed, and a pool was prepared with the optimum quality ejaculates in each replicate. After cryopreservation, spermatozoa were thawed and different in vitro semen quality parameters were evaluated. A discriminant canonical analysis (DCA) was carried out and revealed that total motility (TM; Lambda = 0.301, F = 26,173), hypo-osmotic swelling test (HOST; Lambda = 0.338, F = 22,065), and amplitude of lateral head displacement (ALH, Lambda = 0.442; F = 14,180) were the variables with the highest discriminant power. Finally, a chi-squared automatic interaction detection (CHAID) decision tree (DT) was performed excluding fresh semen samples and ROS was found to be the most valuable variable to discriminate between the different established freezing groups. Samples in the absence of HT or with low concentrations of this antioxidant showed less desirable ROS values in cryopreserved rooster semen. The present study could lead to the improvement of cryopreservation techniques for the genetic material of local poultry breeds and optimize the conservation programs of endangered native avian breeds.

Low-density lipoproteins, resveratrol and quercetin as alternative additives to improve boar semen cooling

Low-density lipoproteins (LDL), quercetin (Q) and resveratrol (R) have been used for sperm preservation to improve sperm quality in different species. To evaluate the effects of LDL, Q and R during the cooling of boar semen. Fifteen boar semen samples were diluted in a BTS extender supplemented with the treatments: LDL at 6%, Q at 10 μM (Q10), 30 μM (Q30) and 50 μM (Q50), or R at 10 μM (R10), 30 μM (R30) and 50 μM. A control without supplementation was included. The semen was stored by cooling at 16°C for 96 h. Every 24 h, sperm motility and kinetics were evaluated using a computer-assisted sperm analyzer (IVOS). At 24 and 96 h of cooling, functional membrane integrity and mitochondrial membrane potential (ΔΨM) of sperm were evaluated by the hypoosmotic swelling test (HOST) an flow cytometry with JC-1 probe, respectively, LDL improved progressive motility of sperm during cooling. Likewise, LDL increased average path velocity (VAP) and straight-line velocity (VSL) and/or curvilinear velocity (VCL) during the first 48 h of cooling. The use of Q between 10 and 30 μM caused a reduction in total motility, progressive motility and amplitude of the lateral head displacement during the entire cooling period, as well as a decrease in VAP, VSL and VCL at 96 h of cooling. LDL, Q10, Q30 and Q50 modulated mitochondrial activity by reducing high-ΔΨM sperm at 0 and 96 h of cooling. During the cooling of the boar semen prior to artificial insemination, the parameters of sperm quality that could influence fertility decrease; however, the inclusion of antioxidants and additives that protect the plasma membrane, such as LDL, could mitigate the damaging effects on spermatozoa. It is concluded that LDL can improve the motility and kinetics of boar semen during cooling while it could modulating the sperm's mitochondrial activity. On the contrary, Q could alter the motility and kinetics of boar sperm during the cooling period.

The influence of L-proline and fulvic acid on oxidative stress and semen quality of buffalo bull semen following cryopreservation

BACKGROUND

This study investigates the effects of cryopreservation and supplementation of Azeri water buffalo's semen with proline (Lp) and fulvic acid (FA).

OBJECTIVES

Therefore, this study aimed to assess motility parameters, sperm viability, oxidative stress parameters, and DNA damage to detect the optimum concentrations of Lp and FA for buffalo semen cryopreservation.

METHODS

Thirty semen samples of three buffalo bulls were diluted in Tris-egg yolk extender and divided into 12 equal groups including control (C), Lp-10, Lp-20, Lp-40, Lp-60, Lp-80 (containing 10, 20, 40, 60, 80 mM L-proline, respectively), FA-0.2, FA-0.5, FA-0.8, FA-1.1, FA-1.4 and FA-1.7 (containing 0.2%, 0.5%, 0.8%, 1.1%, 1.4% and 1.7% fulvic acid, respectively).

RESULTS

The velocity parameters, TM and PM were improved by FA-1.7, FA-1.4, Lp-40 and Lp-60 groups compared to the C group but no significant difference was found regarding the amplitude of lateral head displacement and straightness compared to the control groups. The percentage of sperm viability and PMF were increased by FA-1.7, FA-1.4, FA-1.1, Lp-40 and Lp-60 groups compared to C group, while in terms of sperm DNA damage FA-1.7, FA-1.4, FA-1.1, Lp-10, Lp-20, Lp-40 and Lp-60 groups showed better results compared to C group. The results also showed that FA-1.7, FA-1.4, FA-1.1, Lp-20, Lp-40 and Lp-60 groups could improve TAC, SOD, GSH and decrease MDA levels. Also, FA-1.7, FA-1.4, Lp-20 and Lp-40 groups could improve GPx levels but just FA-1.7, and Lp-40 groups could improve CAT levels compared to C group.

CONCLUSIONS

Thus, it can be concluded that L-proline and fulvic acid supplementations can improve the quality parameters of post-thawed buffalo bull semen.

A new role of H89: Reduces capacitation-like changes through inhibition of cholesterol efflux, calcium influx, and proteins tyrosine phosphorylation during sperm cryopreservation in buffalo

It is a known fact that cryopreservation initiates premature capacitation in spermatozoa during the cryopreservation process. Protein tyrosine phosphorylation is a landmark of cascade reaction accountable for capacitation or capacitation-like changes in spermatozoa. Therefore, our hypothesis was to test an inhibitor (H89) that reversibly inhibits the cascade reaction responsible for capacitation during the cryopreservation process but does not hamper normal capacitation and fertilizing ability of sperm. For this, sixteen ejaculates were collected from Murrah buffalo bulls (n = 4). Each ejaculate was divided into four equal aliquots and diluted in an egg yolk-based semen dilutor supplemented with 0, 2, 10, and 30 μM concentrations of H89 and cryopreserved. Interestingly, H89 reduces cholesterol efflux from spermatozoa and protects spermatozoa from membrane damage during the cryopreservation process. H89 did not prevent lipid peroxidation of the sperm membrane. H89 reduced intracellular calcium concentration in spermatozoa in a dose-dependent manner, but tyrosine phosphorylation reduction was observed in the 2 and 10 μM H89 groups. The CTC assay revealed that the percentage of uncapacitated spermatozoa in different treatment groups increases in a dose-dependent manner. In the in vitro capacitation medium, the effect of H89 is abolished and spermatozoa underwent normal capacitation, but H89-treated spermatozoa attached to zona pellucida in large numbers compared to untreated spermatozoa. In conclusion, H89 does not only inhibit tyrosine phosphorylation of spermatozoa but it reduces cholesterol efflux and calcium influx, and ultimately reduces capacitation-like changes during the cryopreservation process.

Hydroxytyrosol and resveratrol improves kinetic and flow cytometric parameters of cryopreserved bull semen with low cryotolerance

There is considerable interest in breeding programs to "rescue" semen with poor post-thaw fertility from bulls known as "bad freezers". We hypothesized that there may be an interaction between the post-thaw recovery of sperm and the efficacy of antioxidant addition to extenders. The current study assesses the effects of antioxidant additives hydroxytyrosol (HT) and resveratrol (RSV) on the post-thaw semen parameters in two groups of bulls classified as either high or low cryotolerant (i.e., "good" and "bad" freezers). Semen samples were collected from 40 bulls and processed in the extenders containing different concentrations of HT (experiment 1; 0, 25 and 50 µM) and RSV (experiment 2; 0.0, 0.01, 0.1 and 1 mM). In experiment 1, bulls in the low cryotolerance group had a significant improvement in post-thaw recovery at 25 µM and 50 µM (P < 0.05). These improvements were observed in motility and several cellular parameters. However, post-thaw semen quality in the high cryotolerance group was not significantly affected by the HT addition. In experiment 2, although RSV did not have any positive impact in high cryotolerance group, post-thaw recovery in the low cryotolerance bulls was significantly improved in 0.1 mM RSV. Oxidative stress markers in either high or low cryotolerance groups were not significantly changed by RSV addition (P > 0.05). It can be concluded that addition of optimized concentrations of HT and RSV to the extender could be a strategy for improving the post-thaw semen, especially in bulls with high genetic merit but low initial cryotolerance.

Restoring Sperm Quality Post-Cryopreservation Using Mitochondrial-Targeted Compounds

While critical for male fertility preservation, cryopreservation damage reduces sperm quality and fertilization potential. This study investigated whether the addition of mitochondrial-targeted, antioxidant compounds, also known as Mitochondrial activators, to the cryopreservation medium could protect sperm quality during cryopreservation. For this, semen samples from men undergoing IVF/ICSI treatment, which were donated for research, underwent cryopreservation in the absence or presence of BGP-15, MitoQ and L-carnitine. Fresh semen and thawed sperm samples from the same participant were analyzed for indicators of sperm quality: sperm viability, kinetics, mitochondrial reactive oxygen species (ROS) levels, Mitochondrial Membrane Potential (MMP) and DNA damage. Cryopreservation significantly reduced sperm viability and motility and predicted mucous penetration. BGP-15, MitoQ and L-carnitine improved sperm motility, whilst the addition of L-Carnitine prevented the loss of sperm viability during cryopreservation. Both BGP-15 and L-carnitine reduced sperm DNA oxidative damage, but only BGP-15 significantly reduced DNA fragmentation. More importantly, BGP-15 increased sperm predictive mucous penetration and MMP and reduced DNA oxidation. Our results show that the addition of BGP-15 or L-carnitine to the cryopreservation medium improves sperm quality post-thawing, highlighting the potential of mitochondrial antioxidants to improve long-term fertility preservation in males.

Changes of sperm metabolites of Dezhou donkey after cryopreservation

Sperm cryopreservation technology has laid the foundation for promoting the popularity of artificial insemination in donkey reproduction, but the freeze-thaw process can cause sperm damage, and the viability of frozen sperm is greatly reduced, resulting in low insemination ability. Sperm metabolites play an important role in the freezing process of spermatozoa and have a major influence on the freezability of spermatozoa. The aim of this study was to explore the differential metabolites in donkey spermatozoa before and after cryopreservation by liquid chromatography tandem mass spectrometry (LC-MS/MS). We analysed ejaculate samples from male donkeys obtained before and after freezing and identified 1323 metabolites. Compared with fresh sperm (F), the metabolites of cryopreserved sperm (CRY) were significantly changed, and 570 metabolites were significantly different between the two groups (P < 0.05). Among them, 277 metabolites were higher in frozen sperm, while the opposite was true for 293 metabolites. These metabolites mainly include phospholipids, lysophospholipids, and amino acids., most of which are associated with oxidative stress and sperm capacitation. We describe significantly different metabolites before and after freezing that are significantly associated with decreased sperm motility postfreezing and can be used as biomarkers of decreased sperm motility postfreezing.

Resveratrol and lycium barbarum polysaccharide improve Qinling giant panda (Ailuropoda melanoleuca Qinlingensis) sperm quality during cryopreservation

Background

Semen cryopreservation has become an essential tool for conservation efforts of the giant panda (Ailuropoda melanoleuca); however, it is severely detrimental to sperm quality. Evidence has shown that antioxidants have the potential to reverse cryopreservation-induced damage in sperm. The purpose of this study was to screen effective antioxidants that could retain sperm quality during cryopreservation and to determine the optimal dose. Seven antioxidant groups, including resveratrol (RSV = 50 μM, RSV = 100 μM, RSV = 150 μM), lycium barbarum polysaccharide (LBP = 2 mg/mL, LBP = 4 mg/mL), laminaria japonica polysaccharides (LJP = 1 mg/mL) or combination (LBP = 2 mg/mL, LJP = 1 mg/mL and RSV = 100 μM) were assessed.

Results

RSV, LBP, LJP, or a combination of RSV, LBP, and LJP added to the freezing medium significantly improved sperm progressive motility, plasma membrane integrity, acrosome integrity, and mitochondrial activity during the cryopreservation process. Furthermore, the activities of glutathione peroxidase and superoxide dismutase were also improved. The levels of reactive oxygen species and malondialdehyde in semen were notably reduced. Hyaluronidase activity and acrosin activity were significantly increased in LBP-treated sperm. However, sperm total motility and DNA integrity were not significantly different between the groups.

Conclusions

RSV (50 μM) or LBP (2 mg/mL) are the best candidate antioxidants for inclusion in the freezing medium to improve the quality of giant panda spermatozoa during semen cryopreservation.

Effect of Milk Type Subjected to Different Heat Treatments on Cryo-Survivability and In Vivo Fertility of Buffalo (Bubalus bubalis) Spermatozoa in a Milk-Based Extender

Oxidative stress is a major contributory factor to cellular damage during semen cryopreservation and results in a decreased fertilizing capacity of cryopreserved bull sperm. The inclusion of exogenous antioxidants sometimes exerts deleterious effects on sperm quality. Thus, enhancing the endogenous production of antioxidants is a requirement. This study aimed to investigate the effect of milk type heated at different temperatures on the antioxidant potential of extenders, and the subsequent post-thaw quality parameters and in vivo fertility of buffalo bull semen. Cow (C) and buffalo whole milk (B) were used separately for semen extender preparation, heated at five different temperatures (T₁ = 90°C, T₂ = 100°C, T₃ = 110°C, T₄ = 120°C, T₅ = 130°C) for 10 minutes. Reactive sulfhydryl groups were measured in each subgroup by Ellman's reagents as CT₁ = 143.2 μM, CT₂ = 147.4 μM, CT₃ = 151.5 μM, CT₄ = 157.2 μM, CT₅ = 161.8 μM, BT₁ = 168.3 μM, BT₂ = 172.5 μM, BT₃ = 176.7 μM, BT₄ = 196.3 μM, and BT₅ = 205.7 μM. All semen samples were cryopreserved in milk-based extenders by using standard procedures. Post-thaw quality parameters including total and progressive motility, mitochondrial membrane potential, plasma membrane integrity, and acrosome integrity were found to be higher (p < 0.05) in the group (BT₃) containing buffalo milk heated at 110°C, whereas in the same group, lipid peroxidation was found to be lower (p < 0.05) as compared with other treatment groups and control group. In vivo fertility of cryopreserved buffalo sperm was compared among BT₃, CT₁ (conventionally used milk extender), and a Tris egg yolk extender group. The fertility rates [47% (54/114), 30% (33/108), and 36% (37/103)] were higher (p < 0.05) in BT₃ as compared with other groups. This study suggests that buffalo milk heated at 110°C has high antioxidant potential and improves post-thaw quality and in vivo fertility of cryopreserved buffalo bull semen.

Targeted antioxidant delivery modulates mitochondrial functions, ameliorates oxidative stress and preserve sperm quality during cryopreservation

Mitochondria are vital organelles with a multifaceted role in cellular bioenergetics, biosynthesis, signaling and calcium homeostasis. During oxidative phosphorylation, sperm mitochondria generate reactive oxygen species (ROS) at physiological levels mediating signaling pathways essential for sperm fertilizing competence. Moreover, sperm subpopulation with active mitochondria is positively associated with sperm motility, chromatin and plasma membrane integrity, and normal morphology. However, the osmotic and thermal stress, and intracellular ice crystal formation generate excess ROS to cause mitochondrial dysfunction, potentiating cryoprotectant-induced calcium overload in the mitochondrial matrix. It further stimulates the opening of mitochondrial permeability transition pores (mPTP) to release pro-apoptotic factors from mitochondria and initiate apoptotic cascade, with a decrease in Mitochondrial Membrane Potential (MMP) and altered sperm functions. To improve the male reproductive potential, it is essential to address challenges in semen cryopreservation, precisely the deleterious effects of oxidative stress on sperm quality. During semen cryopreservation, the supplementation of extended semen with conventional antioxidants is extensively reported. However, the outcomes of supplementation to improve semen quality are inconclusive across different species, which is chiefly attributed to the unknown bioavailability of antioxidants at the primary site of ROS generation, i.e., mitochondria. Increasing evidence suggests that the targeted delivery of antioxidants to sperm mitochondria is superior in mitigating oxidative stress and improving semen freezability than conventional antioxidants. Therefore, the present review comprehensively describes mitochondrial-targeted antioxidants, their mechanism of action and effects of supplementation on improving semen cryopreservation efficiency in different species. Moreover, it also discusses the significance of active mitochondria in determining sperm fertilizing competence, cryopreservation-induced oxidative stress and mitochondrial dysfunction, and its implications on sperm fertility. The potential of mitochondrial-targeted antioxidants to modulate mitochondrial functions and improve semen quality has been reviewed extensively.

Improving the post-thaw quality of rooster semen using the extender supplemented with resveratrol

Avian spermatozoa are highly susceptible to reactive oxygen species (ROS) produced during the cryopreservation. The aim of the current study was to investigate the antioxidant effects of resveratrol (RSV) during rooster semen cryopreservation. Changes in expression of AMP-activated protein kinase as a possible mechanism behind the beneficial effects of resveratrol were also evaluated. Semen samples were collected from ten Ross broiler breeders (52-wk) using abdominal massage, then divided into 4 equal aliquots and cryopreserved in Beltsville extender that contained different concentrations (0 µM, 0.01µM, 0.1µM, and 1µM) of RSV. higher percentage (P < 0.05) of total motility and membrane integrity was observed in RSV-0.1 compared to the other frozen groups. Moreover, higher percentage of sperm mitochondrial activity was observed in the RSV-0.01 and RSV-0.1 compared to the frozen control (P < 0.05). The lowest percentage of apoptotic like changes was found in the RSV-0.1 in comparison to the other groups (P < 0.05). RSV-0.01 and RSV-1 groups produced the lowest levels of H2O2 and O2- compared to the other frozen groups, respectively. Malondialdehyde (MDA) concentration, velocity average path (VAP), and linearity (LIN) were not affected by different concentrations of RSV (P > 0.05). We observed a dose-dependent increase in AMP-activated protein kinase expression in groups exposed to RSV. Thus, RSV-1 increased AMP-activated protein kinase phosphorylation but had no positive effects on post thaw sperm parameters. Our findings suggest that RSV-0.1 improve thawed sperm functions, and these effects might be mediated through activation of AMP-activated protein kinase.

Nanocarried antioxidants in freezing extenders for boar spermatozoa

Post-thawing cryoinjuries in boar spermatozoa due to oxidative stress may be reduced by adding nanoencapsulated antioxidants to freezing extenders. This study evaluated post-thawing kinetics, structural and biochemical functions of boar spermatozoa frozen with extenders including resveratrol and vitamin E loaded into polymeric nanocapsules. Resveratrol was added at 0 (control), 5, 10, 20, 40 and 80 µg/ml, whereas Vitamin E was added at 0 (control), 50, 100, 200 and 400 µg/ml. Both antioxidants were tested in free and nanoencapsulated presentations. In contact with empty nanocapsules, some sperm kinetics parameters were impaired compared to the control (p < .05), whereas lipoperoxidation declined (p < .05). With inclusion of 40 µg/ml nanoencapsulated resveratrol, some sperm kinetics parameters were improved (p < .01), but sperm motility, structural and biochemical functions did not differ from the control (p > .05). No improvement in sperm quality occurred with inclusion of vitamin E, although sperm kinetics with 400 µg/ml nanoencapsulated vitamin E was reduced compared to the control (p < .01). Inclusion of 40 µg/ml nanoencapsulated resveratrol benefitted boar sperm kinetics after thawing, but no improvement resulted from inclusion of vitamin E.

Overview on the Antioxidants, Egg Yolk Alternatives, and Mesenchymal Stem Cells and Derivatives Used in Canine Sperm Cryopreservation

Sperm cryopreservation is a widely used assisted reproductive technology for canine species. The long-term storage of dog sperm is effective for the breeding of dogs living far apart, scheduling the time of artificial insemination that suits the female, and preventing diseases of the reproductive tract. However, spermatozoa functions are impaired during the freeze-thaw processes, which may decrease reproductive performance. Numerous attempts have been made to restore such impairments, including the use of cryoprotectants to prevent the damage caused by ice crystal formation, and supplementation of antioxidants to reduce reactive oxygen species generation due to osmotic stress during the procedure. Egg yolk derivatives, antioxidants, and, more recently, mesenchymal stem cells (MSCs) and their derivatives have been proposed in this research field. This review article will summarize the current literature available on the topic.

Protective Effect of Chlorogenic Acid on Human Sperm: In Vitro Studies and Frozen-Thawed Protocol

The study evaluated the chlorogenic acid (CGA) antioxidant potential on oxidative stress (OS) induced in vitro in human spermatozoa and during cryopreservation procedure. Swim-up selected spermatozoa were treated with 100 µM CGA, 100 µM H₂O₂ to induce lipid peroxidation (LPO), and with both compounds and the effects on mitochondrial membrane potential (MMP) by JC-1, DNA integrity by acridine orange (AO), and sperm ultrastructure by transmission electron microscopy (TEM), were evaluated. CGA antioxidant activity was assessed by measuring malondialdehyde (MDA) and F₂-isoprostanes (F₂-IsoPs) in the media. The CGA protective activity and the immunolocalization of Phospho-AMPKα (Thr172) were explored in frozen-thawed sperm. CGA was not toxic for sperm motility, DNA integrity and MMP. The increase in MDA (p < 0.05) and F₂-IsoPs (p < 0.001), DNA damage (p < 0.01) and low MMP (p < 0.01) levels after H₂O₂ treatment were reduced in presence of CGA as well as the percentage of broken plasma membranes (p < 0.01) and altered acrosomes (p < 0.01) detected by TEM. Treated frozen-thawed spermatozoa showed increased sperm motility (p < 0.01), DNA integrity (p < 0.01), MMP (p < 0.01), reduced MDA (p < 0.01) and increased sperm percentage with Phospho-AMPKα labelling in the head (p < 0.001). CGA can be used to supplement culture media during semen handling and cryopreservation where OS is exacerbated.

Improving the quality and in vitro fertilization rate of frozen-thawed semen of buffalo (Bubalus bubalis) bulls with the inclusion of vitamin B12 in the cryopreservation medium

This study was designed to evaluate the effects of vitamin B₁₂ in cryopreservation medium on frozen-thawed semen of buffalo (Bubalus Bubalis) bulls. Semen from five bulls (fertility-proven) were diluted in five aliquots not supplemented (control), or supplemented with 1, 2, 4, or 5 mg/mL of vitamin B₁₂ and evaluated using the Computer Assisted Sperm motion Analysis, antioxidant enzymes, lipid peroxidation (LPO), reactive oxygen species (ROS), ATP concentrations, and in vitro fertilization rate (%). Sperm progressive motility, rapid velocity (%), mitochondrial potential, and acrosome integrity were greater (P < 0.05) with supplementation of 4, and 5 mg/mL vitamin B₁₂ than the control sample. Similarly, compared with the control, samples with 5 mg/mL vitamin B₁₂ supplementation had markedly greater average-path, straight-line, and curved-line velocities (μm/sec). Semen samples supplemented with 2, 4 and 5 mg/mL vitamin B₁₂ had greater concentrations of GPx (U/mL) and SOD (U/mL), whereas LPO (μM/mL) was less (P < 0.05) compared with the control sample. Seminal plasma ROS concentrations (10⁴/25 × 10⁶) were less in the 5 mg/mL vitamin B₁₂ supplemented than control sample. Semen samples supplemented with 5 mg/mL of vitamin B₁₂ had greater concentrations of ATP than control and the 1 mg/mL vitamin B₁₂ supplemented sample. Semen samples supplemented with 5 mg/mL of vitamin B₁₂ had greater plasmalemma and DNA integrities (%) than the control sample. In summary, vitamin B₁₂ supplementation augments semen quality, as evidenced by values for CASA variables, antioxidant enzymes, and ATP concentrations, which may occur as a consequence of inhibition in LPO and ROS production by buffalo spermatozoa.

Comparative evidence support better antioxidant efficacy of mitochondrial-targeted (Mitoquinone) than cytosolic (Resveratrol) antioxidant in improving in-vitro sperm functions of cryopreserved buffalo (Bubalus bubalis) semen

The present study compared the effect of mitochondria-targeted (Mitoquinone, MitoQ) and untargeted cytosolic antioxidant (Resveratrol, RESV) supplementation on lipid peroxidation (LPO) and in-vitro sperm functions of cryopreserved buffalo bull semen. To optimize additive's concentration, sperm pellet obtained from twenty-four ejaculates was supplemented with different concentrations of MitoQ (20 nM, 100 nM, 200 nM); and RESV (10 μM, 25 μM, 50 μM) against control in the extender. The post-thaw sperm motility, livability, and membrane integrity were higher (P < 0.05) in 200 nM MitoQ and 50 μM RESV than other concentrations used. In another experiment, sperm pellet from thirty-two ejaculates was supplemented with 200 nM MitoQ and 50 μM RESV in the extender. Pre-freeze and post-thaw progressive motility and livability were higher (P < 0.05) in MitoQ (200 nM) than RESV (50 μM) treatment. MitoQ supplementation improved post-thaw membrane integrity (CFDA-PI) higher (P < 0.05) than RESV, however, hypo-osmotic swelling response observed no improvement with RESV treatment. Post-thaw LPO rate was lower (P < 0.05) and Bovine cervical mucus penetration was higher (P < 0.05) in MitoQ than RESV treatment. In post-thaw semen, MitoQ showed higher (P < 0.05) proportion of acrosome intact (FITC-PNA), live non-apoptotic (P < 0.01) sperm with a higher reduction (P < 0.05) in membrane scrambling. MitoQ improved (P < 0.01) proportion of sperm with high Mitochondrial Membrane Potential and low LPO (P < 0.01) than RESV treatment. In conclusion, improvement in post-thaw in-vitro sperm functions and cryo-tolerance was more evident in MitoQ than RESV supplemented buffalo bull semen. Our study provides a better strategy to mitigate oxidative stress by enhancing mitochondrial antioxidant system with targeted antioxidants than cytosolic antioxidant supplementation.

A systematic review and meta-analysis of spermatozoa cryopreservation, in vitro and in vivo fertility practices in water buffalo

We explored different aspects of buffalo spermatozoa during cryopreservation. The meta-data comprised of 285 studies, published from January 2008 to March 2020. A free web tool CADIMA as well as PRISMA 2009 Flow Diagram were used for carrying out this study. The inter-reviewer agreement among studies allocated was satisfactory for criteria A (selection bias), B (performance bias), C (detection bias) and D (attrition bias), respectively. India led the percent (%) research ladder with 34.4, followed by Pakistan (29.5), Egypt (12.3), Iran (7.7), Italy (5.6), Indonesia (3.2), China (2.1), Brazil (1.4), Thailand (1.1), Philippines and Bulgaria (0.7 each), Saudi Arabia, Turkey, Vietnam, and USA (0.4 each). Among four categories of studies, Group-1 evaluated only supplements/additives/media in the freezing semen extender (n = 191/285; 67.02%); Group-2 conducted in vivo fertilization (n = 62/285; 21.75%) and Group-3 conducted in vitro fertilization/ cleavage rate/penetration rate/ blastocyst yields (n = 28/285; 9.82%) with their specific cryodiluents/media, respectively. Group-4 conducted different experimental supplements/additives/media and carried out both in vitro and in vivo fertilization simultaneously (n = 4/285; 1.40%). Conventional spermatozoa cryopreservation was reported by 51.9% studies followed by programmable fast freezing by 20.7% studies. A few leading extender types included BioXcell (3.9%); Soyamilk-skim (3.5%); and Andromed (2.1%). The study also describes French straws for semen filling, cooling temperatures, extension time, equilibration time, cryopreservation stages, thawing temperatures, seasons, thawing time, and stains used during semen evaluation assays. The study concludes that the research on spermatozoa cryopreservation of buffalo is largely conducted at quality level and a need of applying these findings for evaluation of fertility potential (in vivo and in vitro) is indispensable for effective genetic improvement.

Resveratrol supplementation into extender protects against cryodamage in dog post-thaw sperm

Antioxidants have multiple protective roles in a variety of cells and thus can be used to protect sperm against cryo-damage during freezing, which affects fertility. The antioxidant resveratrol (3,5,4-trihydroxytrans-stilbene; RSV) has been reported to protect the animal sperm during cryopreservation, including human sperm. In this study, we assessed the protective effects of RSV supplementation on dog sperm cryopreservation. Semen was collected from four dogs and the effect of different concentrations of RSV (0, 100, 200, and 400 µM) on post-thaw sperm quality was examined. After thawing, sperm motility was assessed using computer-aided sperm analysis, and the structural integrity of the plasma membrane, acrosome, and chromatin was examined. In addition, their mitochondrial activity and gene expression were also assessed. Dog sperm cryopreserved with 200 µM RSV showed significant improvement in post-thaw sperm motility and viability compared with that of the control group (P<0.05). Moreover, RSV-supplemented samples showed significantly higher numbers of sperm with an intact plasma membrane, active mitochondria, and structural integrity of acrosomes and chromatin than that of control samples (P<0.05). Furthermore, gene expression showed that RSV supplemented samples showed lower expression of pro-apoptotic (BAX), reactive oxygen species (ROS) modulator oxidative stress-related (ROMO1) and 8-oxoguanine DNA glycosylase 1 (OGG1) whereas higher expression levels of anti‐apoptotic (BCL2), protamine-2 (PRM2), protamine-3 (PRM3) and sperm acrosome‐associated 3 (SPACA3) genes than control. Our results suggest that RSV, at its optimum concentration, can be efficiently used as an antioxidant in the cryopreservation of dog sperm.

The Feasibility of Antioxidants Avoiding Oxidative Damages from Reactive Oxygen Species in Cryopreservation

Cryopreservation prolongs the storage time of cells and plays an important role in modern biology, agriculture, plant science and medicine. During cryopreservation, cells may suffer many damages, such as osmotic dehydration, large ice puncture and oxidative damages from reactive oxygen species (ROS). Classic cryoprotectants (CPAs) are failing to dispose of ROS, while antioxidants can turn ROS into harmless materials and regulate oxidative stress. The combination of antioxidants and CPAs can improve the efficiency of cryopreservation while negative results may occur by misuse of antioxidants. This paper discussed the feasibility of antioxidants in cryopreservation.

Effects of resveratrol in bull semen extender on post-thaw sperm quality and capacity for fertilization and embryo development

Resveratrol, a potent antioxidant, can be an alternative semen extender constituent to protect spermatozoa against reactive oxygen species (ROS); however, effects on sperm quality post-thawing and sperm function is not well understood. This study, therefore, was conducted to investigate effects of resveratrol supplementation to semen extender on sperm quality post-thawing. Bull semen was cryopreserved using extenders not supplemented or supplemented with 0.05, 0.1, or 1 mM resveratrol. Supplementation of extender with resveratrol at 0.05 mM resulted in greater (P < 0.05) sperm progressive motility, average path velocity, straight linear velocity, linearity and straightness when compared with no or 1 mM supplementations. Furthermore, effects of 0.05 mM resveratrol supplementations on plasma membrane and acrosome integrity and sperm fertilization capacity using in vitro procedures were investigated. Supplementation of semen extender with resveratrol resulted in a greater (P < 0.05) proportion of frozen-thawed spermatozoa with an intact acrosome and plasma membrane. Results from in vitro fertilization studies indicated there were no differences (P> 0.05) when there was no supplementation or supplementation with 0.05 mM resveratrol on embryo development to the cleavage and blastocyst stages. In conclusion, addition of resveratrol to bull semen extender resulted in greater sperm quality post-thawing in a dose-dependent manner, with values for variables related to sperm quality being greater when there was resveratrol supplementation at the 0.05 mM concentration. Proportion of embryo developing to the cleavage and blastocyst stages after in vitro fertilization was not affected by resveratrol supplementation to semen extenders.

Involvement of progesterone and estrogen receptors in the ram sperm acrosome reaction

The steroid hormones 17-β estradiol (E2) and progesterone (P4) can regulate capacitation, hyperactive motility, and the acrosome reaction (AR) during the sperm transit through the female tract. Moreover, exogenous P4 and E2 can induce the AR in ovine spermatozoa, and progesterone receptor (PR) and estrogen receptors (ERα and ERβ) are present in these cells. Thus, to investigate whether the effects both steroid hormones in ram sperm capacitation and AR are receptor-mediated, we incubated them with receptor agonists (tanaproget 1 μM and 5 μM for PR or resveratrol 5 μM and 10 μM for ER) or antagonists (mifepristone 4 μM and 40 μM for PR or tamoxifen 5 μM and 10 μM for ER) in capacitating conditions. The addition of receptor modulators did not affect sperm viability or total motility, although changes in progressive motility were detected. The incubation with both receptor agonists increased the percentage of acrosome-reacted spermatozoa, evaluated by chlortetracycline staining, when compared with the capacitated nontreated sample (Cap-C, P < 0.001). Moreover, the ER agonist resveratrol 10 μM provoked a greater AR than E2 (P < 0.01). Furthermore, the incubation with the receptor antagonists prevented the induction of the AR by P4 or E2, as the antagonists-treated spermatozoa presented a similar CTC pattern to that of Cap-C. In conclusion, these results confirm that P4 and E2 can induce the AR in ram spermatozoa and that this effect is receptor-mediated.

Increased quality of in natura and cryopreserved semen of water buffaloes supplemented with saturated and unsaturated fatty acids from the palm oil industry

Ruminant energy supplementation with vegetable oils or fats has been standing out worldwide and oil palm processing has been receiving growing interest. This study assessed the effect of supplementation with saturated and unsaturated fatty acids from the palm oil industry on the lipid profile of seminal plasma and of the sperm membrane, as well as on the morphological and functional characteristics of raw and cryopreserved buffalo semen. Twelve purebred Murrah bulls (Bubalus bubalis) were assigned to the experimental groups and fed diets for 120 days with no added lipids (CONT, four bulls), or with an extra amount of 3% lipids from crude palm oil (PALM, four bulls), or from palm oil deodorizer distillate (PODD, four bulls). Semen was collected and cryopreserved every 15 days. The lipid composition of membranes and semen quality were determined after collections. Lipid supplementation did not impact feed intake (P>0.05). Diet enrichment with PALM increased the linoleic acid (C18:2,ω6) in seminal plasma. Lipid supplementation did not increase the polyunsaturated fatty acids in the sperm membrane composition, but significantly increased the lignoceric acid (C24:0). Cryopreserved semen of the supplemented bulls presented higher progressive motility (60.2 vs. 67.9 vs. 65.2%; P<0.05) and sperm viability detected by eosin-nigrosin staining (61.1 vs. 69.4 vs. 67.8%; P<0.05). Palm oil reduced major sperm defects in both raw (12.2 vs. 9.3 vs. 13.2%; P<0.0001) and cryopreserved semen (12.4 vs. 9.4 vs. 11.2%; P<0.0001). The lipids added to the diet did not impact the population of spermatozoa with intact plasma and acrosomal membranes (PI-/PSA-), but significantly increased the percentage of spermatozoa with high mitochondrial potential (25.6 vs. 31.5 vs. 32.0%; P=0.008). The results suggest that lipid supplementation based on crude palm oil or palm oil deodorizer distillate can be safely used to feed buffalo bulls and may increase sperm attributes related to male fertility.

Polyphenols in Farm Animals: Source of Reproductive Gain or Waste?

Reproduction is a complex process that is substantially affected by environmental cues, specifically feed/diet and its components. Farm animals as herbivorous animals are exposed to a large amount of polyphenols present in their natural feeding system, in alternative feed resources (shrubs, trees, and agro-industrial byproducts), and in polyphenol-enriched additives. Such exposure has increased because of the well-known antioxidant properties of polyphenols. However, to date, the argumentation around the impacts of polyphenols on reproductive events is debatable. Accordingly, the intensive inclusion of polyphenols in the diets of breeding animals and in media for assisted reproductive techniques needs further investigation, avoiding any source of reproductive waste and achieving maximum benefits. This review illustrates recent findings connecting dietary polyphenols consumption from different sources (conventional and unconventional feeds) with the reproductive performance of farm animals, underpinned by the findings of in vitro studies in this field. This update will help in formulating proper diets, optimizing the introduction of new plant species, and feed additives for improving reproductive function, avoiding possible reproductive wastes and maximizing possible benefits.

The Role of Resveratrol in Mammalian Reproduction

Resveratrol is one of the most investigated natural polyphenolic compounds and is contained in more than 70 types of plants and in red wine. The widespread interest in this polyphenol derives from its antioxidant, anti-inflammatory and anti-aging properties. Several studies have established that resveratrol regulates animal reproduction. However, the mechanisms of action and the potential therapeutic effects are still unclear. This review aims to clarify the role of resveratrol in male and female reproductive functions, with a focus on animals of veterinary interest. In females, resveratrol has been considered as a phytoestrogen due to its capacity to modulate ovarian function and steroidogenesis via sirtuins, SIRT1 in particular. Resveratrol has also been used to enhance aged oocyte quality and as a gametes cryo-protectant with mainly antioxidant and anti-apoptotic effects. In males, resveratrol enhances testes function and spermatogenesis through activation of the AMPK pathway. Furthermore, resveratrol has been supplemented to semen extenders, improving the preservation of sperm quality. In conclusion, resveratrol has potentially beneficial effects for ameliorating ovarian and testes function.

Crocin Improves the Quality of Cryopreserved Goat Semen in Different Breeds

The effect of crocin in the semen extender before cryopreservation was evaluated on sperm parameters of 20 bucks of five different breeds: Garganica (GA), Jonica (JO), Maltese (MA), Mediterranean Red (MR) and Saanen (SA). Semen samples were centrifuged, to remove seminal plasma, divided in two aliquots and diluted with Tris-egg-yolk-based extender, containing 0 (control group) and 1 mM crocin. Crocin concentration was established after a preliminary dose trial. On fresh and frozen-thawed sperm, motility, viability, morphology, membrane integrity, DNA fragmentation and ROS levels were evaluated. The freezing process led to a decrease (p < 0.05) in all the sperm parameters recorded, confirming the deleterious effect of cryopreservation on goat semen. The most interesting result regarding the inclusion of crocin in the extender before cryopreservation was as follows: Crocin significantly improved (p < 0.05) sperm motility in all breeds, except for Mediterranean Red, compared to the control group. Furthermore, 1 mM crocin reduced percentage of spermatozoa with DNA fragmentation with a marked decrement (p < 0.05) in Garganica and Saanen, as compared to the control group. Finally, intracellular ROS decreased (p < 0.01) in the crocin-treated sperm of all breeds, as compared to the control. In conclusion, supplementation of 1 mM crocin in the extender decreased oxidative stress, improving sperm motility and the DNA integrity of frozen-thawed sperm in different breeds.

Changes in Bull Semen Metabolome in Relation to Cryopreservation and Fertility

Semen cryopreservation determines several sperm damages, including the loss of fertility-associated proteins. The purpose of the study was to compare the metabolite contents in bovine sperm and seminal plasma before and after cryopreservation, and between high- and low-fertility bulls in vitro. Forty-eight ejaculates, collected from eight bulls (six per bull), were analyzed by liquid chromatography-mass spectrometry. Cryopreservation resulted in an over-expression of lysophosphatidylcholine (0:0/18:2(9Z,12Z)) in seminal plasma. In addition, higher levels of glycine betaine and pyro-l-glutaminyl-l-glutamine were observed in cryopreserved compared to fresh spermatozoa. The fresh seminal plasma of high-fertility bulls showed an over-expression of l-acetylcarnitine, glycerol tripropanoate, 2,3-diacetoxypropyl stearate and glycerophosphocholine, and an under-expression of lysophosphatidylcholine and butyrylcarnitine, compared to low-fertility bulls. Higher levels of glycerophosphocholine and lysophosphatidylcholine (16:0/0:0) were recorded in fresh spermatozoa from high-fertility bulls. In high-fertility bulls, a greater content of glycerophosphocholine and lower levels of butyrylcarnitine, glycine betaine and l-carnitine were found in cryopreserved seminal plasma, and lower levels of glycine betaine were detected in cryopreserved spermatozoa. In conclusion, cryopreservation affects bovine semen metabolome at both plasmatic and cellular compartments, and metabolic profile differs between high- and low-fertility bulls.

Resveratrol supplementation and cryopreservation of buck semen

Resveratrol (Resv) was tested to assess its effects on buck semen freezability. Ejaculates of 4 bucks were collected, washed and diluted in a commercial extender at 30 °C. Extended semen was divided into 4 aliquots supplemented with increasing concentrations of Resv: 0 μM (control); 10 μM; 25 μM and 50 μM. Aliquots were cooled to 4 °C in 5h and frozen in LN₂. Thawing was performed at 37 °C for 30 s. At the 3 stages of the experiment (30 °C, 4 °C, thawing), motility (CASA), osmotic resistance (Hos test) and integrity of cytoplasm and acrosome membranes (PI/PSA staining) were assessed. Moreover, in thawed samples, the oxidative status (MDA assay) and early apoptosis (DNA fragmentation by TUNEL assay) were evaluated. Resveratrol supplementation did not affect most of the motility parameters analysed, except for total motility, ALH (lateral head displacement) and velocity distribution (P < 0.05). Functional and morphological integrity of membranes was not affected at any stage of the experiment (P > 0.05). In thawed spermatozoa, the oxidative status was not preserved by Resv (P > 0.05) while early apoptosis, was significantly decreased in the 50 μM Resv group (P < 0.05). Resveratrol did not improve buck semen freezability; the observed effects on motility and DNA were not dose dependent and not mediated by a potential anti-oxidant activity.