Supplementation of soybean lecithin-based semen extender by antioxidants: complementary flowcytometric study on post-thawed ram spermatozoa

Effects of apigenin and trans-ferulic acid on microscopic and oxidative stress parameters in the semen of water buffalo bulls during cryopreservation

Cryopreservation involves exposing sperm to stressful conditions that affect cell viability. The high quality of the Azerbaijani water buffalo's by-products, such as buffalo milk, makes it a species of significant importance. Our focus is on protecting its genetic resources by preserving its sperm, as their numbers will decrease in the coming years and they are at risk of extinction. This study's goal was to ascertain how apigenin (A) and trans-ferulic acid (t-FA) affected the semen quality of Azari water buffalo bulls under cryopreservation. Pooled buffalo sperm (n = 35 ejaculations) were diluted in a Tris-based diluent also containing varying amounts of apigenin (0.2, 0.4, 0.6, and 0.8 mM) and trans-ferulic acid (2.5, 5, 10 and 20 mM). Following a freeze-thaw procedure, samples were assayed for total antioxidant capacity (TAC), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione activity (GSH), glutathione peroxidase (GPx), progressive motility and total motility, motility properties, plasma membrane functionality, and viability. Sixty days after insemination, the rectal examination was performed on 38 buffaloes that had undergone sexual breeding to confirm pregnancy. The results of the study show that the addition of A-0.2, A-0.4, and t-FA-10 to buffalo semen increases the percentage of intact plasma membrane, motility, and sperm viability, as well as the levels of GSH, GPx, CAT. and TAC. In addition, there is a decrease in MDA and DNA damage after cryopreservation. Furthermore, the results show that 0.4 mM apigenin significantly increases conception rates compared to the control group. The base extender of Tris supplemented with A (0.4 and 0.2 mM) and t-FA (10 mM) improves the antioxidant indices of both frozen and thawed buffalo sperm, which in turn improves post-thawing sperm quality and in vivo fertility improves buffalo sperm.

Coenzyme Q10 preserves buck's sperm quality during cryopreservation process in plant-based extender

Cryopreservation of small ruminant's semen is an effective strategy for distributing spermatozoa for reproductive programs, but this process decreases the fertility potential of post-thawed spermatozoa. The aim of this research was to assess the effect of different concentrations of CoQ10 in soybean lecithin (SL)-based extender on buck semen quality during cryopreservation process. Semen samples were collected from five bucks, twice a week, then diluted in the SL-based extender containing different concentrations of CoQ10 as follows: extender containing 0 µM (control, Q0), 0.1 µM (Q0.1), 1 µM (Q1), 10 µM (Q10) and 100 µM (Q100) CoQ10. Motion characteristics, membrane functionality, abnormal morphology, mitochondrial activity, acrosome integrity, viability, apoptotic-like changes, lipid peroxidation, DNA fragmentation and ROS concentration were evaluated after freeze-thawing process. The Q10 resulted in greater (P≤0.05) total motility, progressive motility, average path velocity, membrane integrity, mitochondrial activity, acrosome integrity and viability compared to the other groups. Furthermore, supplementation of freezing extender with 10 µM of CoQ10 presented lower (P≤0.05) apoptotic-like changes, lipid peroxidation, DNA fragmentation and ROS concentration compared to the other groups. Regarding to the protective effect of CoQ10 supplement during cryopreservation process, it could be explored as a potent antioxidant for cryopreservation of buck semen as it preserved the post-thawed buck sperm quality.

Protective Effect of N-Acetylcysteine on Rooster Semen Cryopreservation

Cryopreservation of avian semen is a useful reproductive technique in the poultry industry. However, during cooling, elevated reactive oxygen species (ROS) levels have destructive effects on both quality and function of thawed sperm. The aim of the current study is to investigate the antioxidant effects of N-acetylcysteine (NAC) during rooster semen cryopreservation. Semen samples were collected from ten Ross 308 broiler breeder roosters (32 weeks) and mixed. The mixed samples were divided into five equal parts and cryopreserved in Lake Buffer extender that contained different concentrations (0, 0.01, 0.1, 1, and 10 mM) of NAC. The optimum concentration of NAC was determined based on quality parameters of mobility, viability, membrane integrity, acrosome integrity, lipid peroxidation, and mitochondrial membrane potential after the freeze-thaw process. There was a higher percentage (p < 0.05) of total motility (TM) (60.9 ± 2.4%) and progressive motility (PM) (35.6 ± 1.9%) observed with the NAC-0.1 group compared to the other groups. Significantly higher percentages of viability (74.4 ± 2.3% and 71 ± 2.3%), membrane integrity (76.4 ± 1.5% and 74.7 ± 1.5%) and mitochondrial membrane potential (67.1 ± 1.6% and 66.3 ± 1.6%) were observed in the NAC-0.1 and NAC-1 groups compared to the other frozen groups (p < 0.05). The lowest percentage of lipid peroxidation and nonviable sperm was found in the NAC-0.1 and NAC-1 groups compared to the other groups (p < 0.05). The average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), and acrosome integrity, were not affected by different concentrations of NAC in the thawed sperm (p > 0.05). Both NAC-0.1 and NAC-1 appear to be beneficial for maintaining the quality of rooster sperm after thawing.

MitoQ preserves the quality and fertility of liquid-preserved ram sperm

Supplementing the semen extender with some antioxidants may preserve sperm quality following liquid preservation. The aim of the current study was to evaluate the influence of the use of MitoQ in the semen extender on quality parameters and fertility of liquid-preserved ram semen. In this study, diluted semen samples were divided into five parts and supplemented with 0, 1, 10, 100 and 1000 nM MitoQ. The prepared samples were stored at 3-5 °C for up to 50 h. Motility, viability, mitochondrial activity, membrane integrity, and malondialdehyde concentration of the chilled sperm were assessed at 0, 25, and 50 h. To evaluate reproductive performance, artificial insemination was performed with semen liquid-preserved for 25 h. In results, at 0 h, no difference between the groups was observed. The use of 10 and 100 nM MitoQ resulted in higher (P ≤ 0.05) total motility, progressive motility, membrane integrity, mitochondrial activity, viability, and lower malondialdehyde concentration than the other groups after 25- and 50-h storage. Pregnancy, parturition and lambing rates were higher (P ≤ 0.05) when ewes were inseminated with 25-h chilled semen samples containing 10 and 100 nM MitoQ compared to the control. Therefore, supplementing the semen extender with MitoQ (10 and 100 nM) could be an efficient method to improve the quality and fertility rate of liquid-preserved ram semen.

The mitochondria-targeted antioxidant "MitoQ" preserves quality and reproductive performance of ram spermatozoa cryopreserved in soybean lecithin-based extender

Cryopreservation of ram semen is helpful for distributing proved spermatozoa for reproductive goals, but cold shock has destructive effects on fertility ability of frozen sperm cells. This study was performed to investigate the effect of the novel mitochondria-targeted antioxidant "MitoQ" on ram sperm quality and fertility potential during cryopreservation process. Semen samples were diluted in extenders supplemented with 0, 1, 10, 100 and 1000 nM MitoQ and then frozen according to the standard protocol. Motility and velocity characteristics, lipid peroxidation, acrosome integrity, membrane functionality, mitochondria active potential, viability, apoptosis status, DNA fragmentation, ROS concentration and reproductive performance were evaluated after thawing. In results, 10 and 100 nM MitoQ presented higher (P ≤ 0.05) total motility, progressive motility, average path velocity, acrosome integrity, membrane functionality, mitochondria active potential and viability as well as lower (P ≤ 0.05) lipid peroxidation, apoptosis status, DNA fragmentation and ROS concentration compared to the control group and the other treatments. Moreover, after fertility trial, 10 and 100 nM MitoQ resulted in higher (P ≤ 0.05) pregnancy, parturition and lambing rates than control group. Therefore, MitoQ is able to preserve quality parameters and fertility potential of post-thawed spermatozoa in sheep and it could be an effective additive for supplementation of ram's semen cryopreservation medium during reproductive programs.

Post-Thaw Parameters of Buck Semen Quality after Soy Lecithin Extender Supplementation with Fumaric Acid

The supplementation of cryopreservation media with antioxidants improves the post-thaw quality and fertilizing ability of spermatozoa. To maximize the fertility of frozen-thawed buck spermatozoa, further research is required to overcome obstacles that have yielded controversial results and standardize protocols. In the present work, the effect of adding fumaric acid (a well-described antioxidant) to a soy lecithin semen extender on certain quality parameters of spermatozoa following freezing and thawing was examined for the first time. Five sexually mature Skopelos bucks were used, and ejaculates were collected with an artificial vagina. The semen samples (98 samples, five replicates) were diluted (400 × 106 spermatozoa/mL) with OviXcell®, supplemented with fumaric acid (0 mM, 2.15 mM, 10 mM or 30 mM), equilibrated (5 °C; 3 h), packed (0.5 mL straws), frozen and stored (-196 °C) until further processing. After thawing, the spermatozoa total and progressive motility (CASA), viability (eosin-nigrosin), membrane functional integrity (HOST), acrosome integrity (SpermBlue®) and mitochondrial function (Rhodamine-123/SYBR-14/PI) were evaluated. Statistical analysis was performed with one-way ANOVA, followed by Duncan's test; significance was set at 0.05. The addition of 2.15 mM fumaric acid improved (p < 0.05) spermatozoa viability, membrane functional integrity, acrosome integrity and mitochondrial function compared to all other concentrations. The addition of 30 mM fumaric acid decreased (p < 0.05) spermatozoa viability and mitochondrial function compared to all other concentrations. These results indicate a beneficial effect of a 2.15 mM fumaric acid addition to a soy lecithin extender on post-thaw buck spermatozoa quality. Further research is required to evaluate the in vivo fertility of frozen-thawed buck spermatozoa treated with fumaric acid, as well as to elucidate the mechanism of action of fumaric acid in spermatozoa.

Determining the Optimal Dosage of Lecithin Nanoliposome in Rooster Semen Freezing Medium and Fertility Potential

Introduction: Lecithin nanoliposome (nano-LPO), with its cryoprotective properties, is considered to enhance the performance of a traditional semen cryoprotectant. Objective: To determine the optimal dose of lecithin nano-LPO added to the rooster semen extender. Materials and Methods: Semen samples collected weekly from eight broiler breeder roosters were mixed and aliquoted into five equal subsamples, during the five successive weeks. The subsamples were then diluted with a semen extender containing 0%, 0.5%, 1%, 1.5%, or 2% of lecithin nano-LPO. Post-thawed semen quality attributes, including sperm motility and velocity parameters, plasma membrane functionality, mitochondrial membrane potential (MMP), apoptosis-like changes, and fertility potential, were evaluated. Results: Total motility and velocity parameters, including curvilinear velocity (VCL), straight-line velocity (VSL), average path velocity μm/s (VAP), straightness (STR), linearity (LIN), lateral head displacement (ALH), and wobble (WOB) were quadratically (p < 0.01) influenced by graded levels of lecithin nano-LPO, such that the highest values were obtained when 1% of lecithin nano-LPO was used. Treatments had no significant effect on plasma membrane functionality; however, MMP (p < 0.08) and percentages of live and dead spermatozoa (p < 0.05) quadratically responded to increasing levels of lecithin nano-LPO, where the best outcome was found when about 1% of lecithin nano-LPO was used in the semen extender. The percentage of apoptotic spermatozoa cubically responded to increasing levels of lecithin nano-LPO (p ≤ 0.07). No significant trend of fertility rate was found in response to addition of lecithin nano-LPO levels. Conclusions: Supplementing an extender with 1.10% of lecithin nano-LPO is shown to be the optimal dose associated with the most improvement in post-thawed rooster sperm velocity measurements.

The Cryopreserved Sperm Traits of Various Ram Breeds: Towards Biodiversity Conservation

The aim of our research was to compare three Slovak sheep breeds in the quality parameters of cryopreserved sperm. The ejaculates of Slovak Dairy (SD), Native Wallachian (NW), and Improved Wallachian (IW) sheep rams (n = 12) were collected by electro-ejaculation. Heterospermic samples were created from suitable ejaculates, separately for each breed (at least 90% of total and 80% of progressive motility). Samples were equilibrated in a Triladyl® diluent and frozen by automated freezing. Sperm samples were subjected to the motility, morphology, (CASA), viability and apoptosis (DRAQ7/Yo-Pro-1), fertilizing capability (penetration/fertilization test (P/F) in vitro) and acrosomal status (transmission electron microscopy) assays before freezing and after thawing. It was found that there were no significant differences (p < 0.05) between the evaluated breeds in motility, viability, apoptosis, morphological properties, and fertilizing ability of cryopreserved sperm. Significant differences occurred in acrosomal status. Our results demonstrate that the use of the selected cryopreservation protocol is suitable for at least three different sheep breeds, which can greatly benefit the biodiversity protection and simplifies the creation of an animal genetic resources gene bank.

Cryopreservation of ram semen: Manual versus programmable freezing and different lengths of equilibration

The aim of our study was to examine effects of the length of semen equilibration as well as two freezing techniques on ram sperm post-thaw quality. The ejaculates of Wallachian sheep rams (n = 12) were collected by an electro-ejaculation, equilibrated in a Triladyl® (0, 2, 4, 6, and 8 h) containing glycerol and egg yolk and frozen by programmable freezing (PF) or manual freezing (MF). After thawing, sperm samples were subjected to the motility (computer-assisted sperm analysis [CASA]), viability (SYBR-14/PI), and fertilizing ability (FA) (in vitro penetration/fertilization test on bovine oocytes) assays. It was found that the equilibration of 6 h (E-6) ensured higher post-thaw sperm motility and progressive movement compared with other lengths tested, irrespective of a freezing technique. The E-6 sperm viability did not differ between PF and MF but was lower (P < 0.05) than control. Sperm FA (E-6) was similar in PF (60.44%) and MF (62%) but slightly lower than in fresh (72.8%). Our data demonstrate that the use of MF was comparable with PF, which can be applied in the field conditions without need in a piece of cost-expensive equipment, which can greatly benefit the gene bank of animal genetic resources.

Supplementation of ram's semen extender with Mito-TEMPO II: Quality evaluation and flow cytometry study of post-thawed spermatozoa

Cryopreservation is an effective method to spread qualified ram spermatozoa for reproductive goals in different farms, but cryopreservation's shocks reduce sperm quality. This study investigated the efficacy of the new mitochondria-targeted antioxidant Mito-TEMPO on post-thawed quality of spermatozoa in sheep. Collected samples were divided into five groups and after dilution, received different doses of Mito-TEMPO (0, 0.5, 5, 50 and 500 µM), and frozen. Thawed sperm motility parameters, malondialdehyde content, membrane functionality, abnormal morphology, mitochondria activity, acrosome integrity, DNA fragmentation, ROS concentration, viability and apoptotic-like changes, were evaluated. According to the results, Mito-TEMPO (5 and 50 μM) improved (p ≤ 0.05) motility parameters, average path velocity, membrane functionality, mitochondria activity and viability compared with the other groups. Moreover, apoptotic-like changes, lipid peroxidation and ROS concentration were lower (p ≤ 0.05) in groups received 5 and 50 μM Mito-TEMPO. Mito-TEMPO showed no effect (p > 0.05) on sperm acrosome integrity, morphology and DNA fragmentation. In conclusion, Mito-TEMPO as a targeted antioxidant could be an efficient cryo-additive to enhance quality parameters of post-thawed ram semen.

Fertility and flow cytometry evaluations of ram frozen semen in plant-based extender supplemented with Mito-TEMPO

Semen cryopreservation is an effective strategy for distributing spermatozoa for artificial insemination, but this process reduces the fertility potential of post-thawed spermatozoa. The current study was conducted to assess effects of the novel mitochondria-targeted antioxidant "Mito-TEMPO" on ram sperm quality and fertility potential during the freeze-thawing process in a plant-based extender. Semen samples were diluted in extenders supplemented with 0, 0.5, 5, 50 and 500 µM Mito-TEMPO and then frozen using a standard protocol. Motility, abnormal morphology, acrosome integrity, membrane integrity, mitochondria membrane potential, viability, apoptotic-like changes, lipid peroxidation, DNA fragmentation, H2O2 concentration and fertility potential were assessed after thawing. Results indicated that with the 5 and 50 μM Mito-TEMPO there was a greater (P ≤ 0.05) percentage of sperm total motility, progressive motility, acrosome integrity and viability as well as less (P ≤ 0.05) lipid peroxidation and late apoptotic-like changes. Membrane integrity and mitochondria membrane potential were greater (P ≤ 0.05) with the 50 μM Mito-TEMPO extender supplementation. Furthermore, with 0.5, 5 and 50 μM Mito-TEMPO supplementations there was a greater (P ≤ 0.05) average path velocity and lesser (P ≤ 0.05) percentages of spermatozoa with DNA fragmentation and relatively greater H2O2 concentration. Results from the fertility experiment indicated the 5 and 50 μM Mito-TEMPO treatments resulted in greater pregnancy, parturition and lambing rates. It, therefore, is concluded that Mito-TEMPO may enhance quality and fertility potential of post-thawed semen of rams.

The effects of varying concentrations of glutathione and trehalose in improving microscopic and oxidative stress parameters in Turkey semen during liquid storage at 5 °C

Since turkey reproduction is mainly through artificial insemination, short-term preservation of turkey semen is one of the most important issues in turkey reproduction management. The present study investigates the effects of glutathione (GSH) and trehalose on lipid peroxidation degree and turkey semen quality while being stored at 5 °C for 72 h. To this end, semen samples were collected from 20 turkeys with a weekly frequency for 12 weeks. A glucose-based extender was used to dilute the pooled semen. It was divided into seven equal parts with varying levels of glutathione [0.5, 1 and 2 mM), trehalose [50, 75 and 100] and control [extender without antioxidant]. Subsequently, the divided semen samples were stored at 5 °C for 72 h. Several sperm parameters such as motility and motion parameters, plasma membrane integrity (PMI), plasma membrane functionality, DNA integrity, and oxidative parameters were assessed following storage for 0, 24, 48, and 72 h. The obtained results indicated an improvement in the plasma membrane functionality and DNA integrity, along with the percentages of PMI in GSH-2 mM group in comparison to the control group following storage at 5 °C for 72 h (P ≤ 0.05). It is also notable that the 2 and 1 mM concentrations of GSH increased the spermatozoa motility and motion parameters in comparison to the control group, respectively (P ≤ 0.05). The study results indicated that GSH-2, 1 mM and trehalose- 100 mM concentrations reduced lipid peroxidase levels and increased total antioxidant activity, catalase, superoxide dismutase, and glutathione peroxidase in comparison to the control group (P ≤ 0.05). Our study's data show that improvement of semen parameters and oxidative stress parameters of turkey semen can be improved by glutathione at 2 and 1 mM and trehalose at 75 mM while storing it 5 °C.

Bayesian Analysis of the Effects of Olive Oil-Derived Antioxidants on Cryopreserved Buck Sperm Parameters

The present study evaluates the effect of olive oil-derived antioxidants, hydroxytyrosol (HT) and 3,4-dihydroxyphenylglycol (DHPG), on cryopreserved caprine sperm using Bayesian inference of ANOVA. For this proposal, sperm was collected, pooled and diluted in freezing media supplemented with different concentrations of HT, DHPG and the mixture (MIX) of both antioxidants. Sperm motility, viability, acrosome integrity, mitochondrial status, and lipid peroxidation (LPO) were assessed in fresh and frozen-thawed sperm samples. The results provided evidence that HT at low concentrations improves sperm motility and viability, and reduces the LPO. Contrastingly, DHPG and MIX exert a positive effect by reducing LPO values as concentration increases. Additionally, mitochondrial potential was reduced when samples were supplemented with HT at low concentrations and mixture of both antioxidants. Conclusively, the addition of olive oil-derived antioxidants (HT at 10 µg/mL and DHPG at 30 µg/mL) implements a protective effect in cryopreserved buck sperm. Bayesian analysis alternatives offer new possibilities to determine the repercussion of antioxidants on sperm, both quantitatively and qualitatively.

Supplementation of ram's semen extender with Mito-TEMPO I: Improvement in quality parameters and reproductive performance of cooled-stored semen

Supplementation of cooling medium with some antioxidants could be a helpful way to improve sperm quality during chilling process. The current study was aimed to assess the influence of using Mito-TEMPO in cooling medium on quality parameters and reproductive performance of sheep semen during chilling process. In this study, diluted semen samples were assigned into 5 parts, and received 0, 0.5, 5, 50 and 500 μM Mito-TEMPO. The prepared samples were stored at 5 °C up to 48 h. Chilled sperm motility, viability, abnormal morphology, mitochondrial membrane potential, membrane functionality and malondialdehyde concentration were assessed during 0, 24 and 48 h. For evaluation of reproductive performance, artificial insemination was performed via 24 h-chilled semen. In results, at time 0, no difference was observed among groups. Using 5 and 50 μM Mito-TEMPO resulted in higher (P ≤ 0.05) cooled sperm total motility, progressive motility, membrane functionality, viability and lower malondialdehyde concentration than the other groups during 24 and 48 h storage. The rate of mitochondrial membrane potential was greater (P ≤ 0.05) in treated groups with 5, 50 and 500 μM Mito-TEMPO. Pregnancy, parturition and lambing rates were higher (P ≤ 0.05) when ewes were inseminated with 24 h-chilled semen samples containing 5 and 50 μM Mito-TEMPO compared to the control group. Therefore, supplementation of cooling medium with Mito-TEMPO (5 and 50 μM) could be an efficient method to improve the quality and reproductive efficiency of ram's cooled semen during storage period.

The possibility of using citric phosphate dextrose in chilling ram semen instead of egg yolk and soybean lecithin to improve fertility

Semen chilling has some harmful effects on sperm characteristics. Modification of extenders by using conventional and non-conventional chilling substances can affect sperm characteristics and fertility. One of the important substances using to chilling human blood cells is citric phosphate dextrose (CPD); therefore, it can be used to store ram semen. This study aimed to assay the ability of CPD instead of egg yolk (EGD) and soybean lecithin (SLD)-based extenders to store ram semen at 5°C. This trial was carried on pooling semen samples that were collected from five rams using a standard artificial vagina and an oestrous restrained ewe. Immediately after semen collection, semen was divided into four portions. The EGD, SLD and citric phosphate dextrose with an antibiotic (CPDA) and without antibiotic (CPD) were extender in the first, second, third and fourth portions of semen, respectively. Sperm characteristics were evaluated after dilution and cooling up to 7 days. Also, conception rate and fertility potential were assayed by 48 ewes (12 each) after 2 days of store ram semen extenders. Data clearly indicated that higher (p > .05) sperm characteristics in EGD, SLD and CPDA than CPD at 0 day of storage. Whilst, sperm characteristics from 1 day up to 7 days of storage were higher (p < .05) in EGD, SLD, CPDA extenders than CPD. Moreover amongst extender types, the advancing of chilling days reduced sperm characteristics. Also, the results showed an acceptable conception rate and the fertility rate of dilution ram semen, which stored 2 days in EGD, SLD and CPDA than CPD. Using of CPD substances with antibiotic in chilling extension ram semen has benefits as well as EGD- and SLD-based extenders. The future work should be conducted to validate these results in frozen ram semen.

The mitochondria-targeted antioxidant Mito-TEMPO conserves rooster's cooled semen quality and fertility potential

The PUFAs content of rooster sperm cells makes them vulnerable to the thermal shocks during chilling storage, which reduces the fertility performance of cooled sperm. Extender supplementation with antioxidants is a reasonable method to conserve sperm fertility potential during cooling storage process. The aim of this study was to determine the effect of Mito-TEMPO addition to the Lake medium on rooster sperm quality and fertility potential during cooling process. Semen samples were diluted in the Lake medium and assigned into five equal aliquots and supplemented with 0, 0.5, 5, 50 and 500 μM Mito-TEMPO. Then, the samples were cooled at 5 °C and conserved up to 50 h. Total motility, progressive motility, morphology, viability, membrane integrity, lipid peroxidation and mitochondrial activity of samples were analyzed during 0, 25 and 50 h of cooling period. Artificial insemination was also conducted using 25 h-cooled semen. No significant difference was observed among different treatments during quality evaluations at 0 h storage. Extender supplementation with 5 and 50 μM Mito-TEMPO presented greater (P ≤ 0.05) total motility, progressive motility, viability, membrane integrity and lower lipid peroxidation compared to other groups during 25 and 50 h cooling storage. Mitochondrial activity was higher (P ≤ 0.05) in groups received 5, 50 and 500 μM Mito-TEMPO than others. Fertility rate of 25 h-cooled-stored samples was higher (P ≤ 0.05) in groups containing 5 and 50 μM Mito-TEMPO compared to control group. In conclusion, addition of 5 and 50 μM Mito-TEMPO as a mitochondria-targeted antioxidant to the storage medium could be a suitable method to conserve rooster semen quality against stressful conditions of cooling storage process.

Quercetin supplemented casein-based extender improves the post-thaw quality of rooster semen

The advantageous influence of quercetin (Q) supplementation in an extender has not yet been evaluated for rooster semen cryopreservation. This research was purposely conducted in order to assess the effect of different quercetin concentrations added into an extender on the sperm quality of the rooster subsequent to a freezing-thawing process. After the freezing-thawing process, spermatozoa quality parameters (membrane functionality, acrosome integrity, motility, viability, and abnormal morphology), endogenous enzymes (SOD, CAT, and GPx), mitochondrial activity, DNA fragmentation index, lipid peroxidation (MDA), and ROS were all evaluated. A total of 75 neat pooled ejaculates (3 ejaculates/rooster) were collected from 25 arbor acres roosters (24 wks) twice a week using abdominal massage technique, then divided into five equal aliquots and diluted with an extender containing different doses of Q (CS-Q) as follows: casein extender without Q (control only), casein extender containing 0.040 mg/mL quercetin (CS-Q 0.040), 0.020 mg/mL quercetin (CS-Q 0.020), 0.010 mg/mL quercetin (CS-Q 0.010), and 0.005 mg/mL quercetin (CS-Q 0.005). Our results depicted that adding to the extender with a 0.010 mg/mL Q enhanced (P < 0.01) sperm motility, membrane function, viability, mitochondrial activity, intact acrosome (P < 0.05), SOD (P < 0.001), CAT, and GPx (P < 0.01) compared to the control group at post-thaw. Compared to the control group and other treatment groups after the freeze-thawing process, the addition of 0.005 mg/mL Q into the extender also showed higher (P < 0.05) improvement in the quality of sperm parameters and a higher (P < 0.01) SOD and CAT but did not improve mitochondrial activity and sperm viability. In addition, there was a lower degree of DNA fragmentation index, lower (P < 0.05) lipid peroxidation and ROS in frozen-thawed sperm treated with 0.010 mg/mL and 0.005 mg/mL Q than in control and the other treatment groups. In addition, 0.020 mg/mL Q supplementation into the extender also reduced DNA fragmentation and improved GPx activity compared to the control group at post-thaw. Different concentrations of Q 0.010 and 0.005 mg/mL added to the extender reduced the percentage of abnormal spermatozoa compared to the other groups. The results of this study showed for the first time that the inclusion of an extender with a suitable quercetin concentration of 0.010 mg/mL improved the post-thawed quality of rooster semen.

Effect of quercetin loaded liposomes or nanostructured lipid carrier (NLC) on post-thawed sperm quality and fertility of rooster sperm

The aim of this study was to investigate the effects of 10, 15 and 20 μM quercetin, alone or loaded in nanoliposomes or in nanostructured lipid carrier (NLC) on sperm rooster cryopreservation and fertility performance. Sperm motility, viability, abnormalities, membrane integrity, mitochondrial activity, apoptosis status, lipid peroxidation (LP), GPX, SOD, TAC and fertility and hatchability rate were investigated after freeze-thawing. A significantly higher percentage (P < 0.05) of sperm total motility was obtained in sperm cryopreserved with 15 μM quercetin loaded NLC compared to diluent with 10 and 20 μM quercetin and to 10, 15 and 20 μM quercetin loaded nanoliposomes, 20 μM quercetin loaded NLC and control group. Also, 15 μM quercetin loaded NLC was significantly higher in progressive motility, VSL, VAP and VCL parameters compared to control group. The percentage of viability, membrane integrity, mitochondria activity, TAC, and GPx increased in semen exposed to 15 μM quercetin loaded NLC group. Likewise, the lowest level (P < 0.05) of malondialdehyde (MDA) was acquired in samples treated with 15 μM quercetin and quercetin loaded NLC group in comparison to the control group. Abnormal form, SOD, and early apoptosis were not (P > 0.05) affected by different levels of quercetin. Fertility and hatchability rate showed higher levels in 15 μM quercetin and quercetin loaded NLC group compared with control group. In conclusion, it seems that quercetin loaded NLC enhanced the antioxidant effect of quercetin by improving post-thawed sperm quality and fertility of rooster sperm.

Ultra-rapid cooling of ibex sperm by spheres method does not induce a vitreous extracellular state and increases the membrane damages

Sperm cryopreservation by ultra-rapid cooling based on dropping small volumes of sperm suspension directly into liquid nitrogen, has been successful in some wild ruminant species, including the Iberian ibex (Capra pyrenaica). In ultra-rapid cooling, the contents of these droplets are expected to enter a stable, glass-like state, but to the best of our knowledge no information exists regarding the presence or absence of ice formation in the extracellular milieu when using this technique. Different modifications to the extracellular milieu likely inflict different types of damage on the plasmalemma, the acrosome and mitochondrial membranes. The aims of the present work were: 1) to examine the physical state of the extracellular milieu after cryopreservation at slow and ultra-rapid cooling rates—and thus determine whether ultra-rapid cooling vitrifies the extracellular milieu; and 2) to compare, using conventional sperm analysis techniques and scanning and transmission electron microscopy, the damage to sperm caused by these two methods. Sperm samples were obtained by the transrectal ultrasound-guided massage method (TUMASG) from anesthetized Iberian ibexes, and cryopreserved using slow and ultra-rapid cooling techniques. Sperm motility (22.95 ± 3.22% vs 4.42 ± 0.86%), viability (25.64 ± 3.71% vs 12.8 ± 2.50%), acrosome integrity (41.45± 3.73% vs 27.00 ± 1.84%) and mitochondrial membrane integrity (16.52 ± 3.75% vs 4.00 ± 0.65%) were better after slow cooling (P<0.001) than after ultra-rapid technique. Cryo-scanning electron microscopy (Cryo-SEM) suggested that the vitrified state was not achieved by ultra-rapid cooling, and that the ice crystals formed were smaller and had more stretchmarks (P<0.001) than after slow cooling. Scanning electron microscopy revealed no differences in the types of damage caused by the examined techniques, although transmission electron microscopy showed the damage to the plasmalemma and mitochondrial membrane to be worse after ultra-rapid cooling. In conclusion ultra-rapid cooling provoked more membrane damage than slow cooling, perhaps due to the extracellular ice crystals formed.

Supplementation of green tea extract (GTE) in extender improves structural and functional characteristics, total antioxidant capacity and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa

The aim of this study was to elucidate the beneficial effects of green tea extract (GTE) in tris citric acid extender on post thaw structural and functional characteristics, DNA fragmentation (%), total antioxidant capacity (TAC, μM/L), lipid peroxidation (LPO, μM/mL) levels and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa. GTE is a acknowledged natural antioxidant, act as a free radical scavenger and protects spermatozoa against oxidative stress. Three mature and donor buffalo bulls were used in this experiment. Two ejaculates were collected per bull on each collection day, followed by initial evaluation for consistency (colour), volume (mL), progressive motility and concentration (x10⁹) and were diluted in five extenders @ 50 x 10⁶/ mL (C = control, no GTE; T1 = treatment 1, GTE 0.1%; T2 = treatment 2, GTE 0.5%; T3 = treatment 3, GTE 0.75% and T4 = treatment 4, GTE1.0%). The experiment was repeated thrice. Data analysis showed that sperm progressive motility (%), plasma membrane integrity (%), supravital plasma membrane integrity (%), viable sperm with intact acrosome (%) and TAC were significantly higher (P < 0.05) in extender supplemented with T4 as compared to control. Furthermore, sperm DNA fragmentation and occurrance of LPO in buffalo bull spermatozoa were significantly lowered in T4 than control. In vitro longevity (%) of spermatozoa was significantly higher in T4 compared to control during 45 and 90 min of incubation at 37 °C. In vivo fertility rate of buffalo bull spermatozoa was significantly higher in T4 compared to control (64.96 vs. 48.40%, P < 0.05). It is concluded that supplementation of tris citric acid extender with 1.0% GTE improved structural and functional characteristics, TAC, in vitro longevity (%) and in vivo fertility, whereas decreased DNA fragmentation and LPO occurrence in buffalo bull spermatozoa after freezing and thawing protocol.

Pre-conditioning with Xanthine oxidase to improve post thawed quality of bull sperm

The purpose of this study was to examine the effects of sub-lethal concentration of Xanthine oxidase (XO) on the post-thawed bull sperm quality. Semen samples were collected from four Holstein bulls, twice a week and during three consecutive weeks (n = 24 total ejaculates). After collection in each replicate, semen samples were pooled and then frozen by semen extender containing different concentrations [0 (XO-0), 0.05 (XO-0.05), 0.5 (XO-0.5), 5 (XO-5), 50 (XO-50) and 500 (XO-500) μM] of XO. After thawing, motion parameters (SCA), plasma membrane functionality (HOST), apoptosis status (Phosphatidylserine translocation assay), mitochondrial activity (Rhodamine 123), and acrosome integrity (PSA), were evaluated. The results showed that total motility, VAP, VSL, VCL, STR, and LIN were lower in XO-50 and XO-500 compared to other groups (P < 0.05). Progressive motility were higher in XO-0.05 and XO-0.5 compared to XO-0, XO-50, and XO-500 (P < 0.05). Mitochondrial activity was highest in XO-0.05 and XO-0.5 groups. Sperm plasma membrane functionality was significantly greater in XO-0, XO-0.05, XO-0.5, and XO-5 than that of XO-50 and XO-500. Xanthine oxidase had not significant effects on acrosome integrity and dead spermatozoa. Higher percentage of live spermatozoa was recorded for XO-0, XO-0.05, XO-0.5, and XO-5; however, the lower amount of apoptotic spermatozoa was detected in the aforementioned groups (P < 0.05). In conclusion, it seems that XO at lower doses may have beneficial effects on post-thawed bull sperm quality.

Effects of CoQ10 on the quality of ram sperm during cryopreservation in plant and animal based extenders

The purpose of this study was to evaluate the effect of different concentrations of CoQ10 in soybean lecithin (SL) or egg yolk (EY) extenders on ram semen cryopreservation. Semen samples were collected from five rams, twice a week, then diluted in the extenders (SL and EY) containing different concentrations of CoQ10 as follows: extender containing SL: 0 μM (control, SL/Q0), 1 μM (SL/Q1), 2 μM (SL/Q2), 5 μM (SL/Q5) and 10 μM (SL/Q10) CoQ10; extender containing EY: 0 μM (control, EY/Q0), 1 μM (EY/Q1), 2 μM (EY/Q2), 5 μM (EY/Q5) and 10 μM (EY/Q10) CoQ10. Sperm motion characteristics, membrane integrity, abnormal morphology, viability, apoptotic-like changes, mitochondria active potential, acrosome integrity and lipid peroxidation were evaluated after freeze-thaw process. The SL/Q1, SL/Q2, EY/Q1 and EY/Q2 resulted in greater (P ≤ 0.05) sperm total motility, progressive motility, membrane integrity and mitochondria active potential compared to the other groups. Acrosome integrity in the SL/Q0, SL/Q1, SL/Q2, EY/Q0, EY/Q1 and EY/Q2 groups was greater (P ≤ 0.05) than in the SL/Q5, SL/Q10, EY/Q5 and EY/Q10 groups. The SL/Q2 and EY/Q2 treatment groups had greater (P ≤ 0.05) sperm viability rates and less apoptotic-like changes and lipid peroxidation. The CoQ10 compound could be explored as a novel potential antioxidant for cryopreservation of ram semen because with used of this compound in the present study there was an improved post-thawed sperm quality.

Improvement of rooster semen quality using coenzyme Q10 during cooling storage in the Lake extender

Sensitivity of rooster semen to stressful condition of cooling restricts the semen storage in commercial flocks for artificial insemination. This study was accomplished to investigate the effect of coenzyme Q10 (CoQ10) addition to the Lake extender during chilled-storage on the parameters of sperm quality and fertility performance. Roosters' pooled semen samples were assigned into equal parts and diluted with Lake extender supplemented with different concentrations of CoQ10 (0, 1, 2, 5 and 10 μM CoQ10). Then, semen samples were cooled to 5 °C and stored over 48 h. Total and progressive motilities, abnormal morphology, viability, membrane functionality, lipid peroxidation (LPO) and mitochondria active potential of diluted sperm were evaluated at 0, 24 and 48 h of cooling storage. Fertility performance of cooled stored semen was examined at 24 h of cooling storage. Although CoQ10 did not affect sperm quality at the starting time of cooling storage (0 h), extender supplementation with 5 μM of CoQ10 showed higher (P ≤ 0.05) sperm total and progressive motilities, membrane functionality, viability and mitochondria active potential at 24 h as well as total motility, viability and membrane functionality at 48 h in contrast with other groups. Moreover, lipid peroxidation was lower (P ≤ 0.05) in semen samples diluted with 5 μM CoQ10 at 24 and 48 h compared to others. After artificial insemination with 24 h chilled-stored sperm, fertility efficiency was higher (P ≤ 0.05) in treatments contained 5 μM CoQ10 compared to the control group. According to the results, using optimum dose of CoQ10 could be helpful to save rooster semen against chilled storage structural and functional damages.

Does fennel extract ameliorate oxidative stress frozen-thawed ram sperm?

The aim of this study was to evaluate the quality of ram semen after cryopreservation with different levels of fennel (Foeniculum vulgare) extract (0 (F0), 5 (F5), 10 (F10) and 15 (F15) mg/L) and sperm concentrations (200 (C200) and 400 (C400) × 10⁶ sperm/mL) in a soy lecithin (SL)-based extender. Twenty ejaculates were collected from four ghezel rams and diluted with eight sperm concentrations/fennel combinations: F0C200, F5C200, F10C200, F15C200, F0C400, F5C400, F10C400 and F15C400. Sperm motility, abnormality, plasma membrane, viability, mitochondrial activity, lipid peroxidation (LPO), mitochondrial activity and apoptotic changes were evaluated after freeze-thawing process. It was observed that F10C400 significantly improved total and progressive motility, VSL, membrane integrity of post-thawed ram sperm. MDA level was lower in F5C200 and F10C400 compared to other treatments. The higher percentage of live sperm and the lower percentage of apoptotic sperm were obtained in F10C200 compared to F0C200, F5C200 F15C400, F0C400, F5C400 and F15C400. Extender F10C200 resulted in the highest mitochondria activity compared to the rest of the extenders except F10C400. We conclude that a combination of 10 mg/mL fennel (Foeniculum vulgare) extract and sperm concentration of 200 × 10⁶ sperm/mL can improve the ram semen quality cryopreserved in a soybean lecithin based extender.

Improvement of post-thawed sperm quality in broiler breeder roosters by ellagic acid-loaded liposomes

Liposomes could improve the delivery of substances to sperm. This study was conducted to investigate the effect of the antioxidant ellagic acid and ellagic acid-loaded liposomes on post-thawed sperm quality in broiler breeder roosters. Semen was diluted in Beltsville extender containing ellagic acid or ellagic acid-loaded liposomes (ellagic acid at 0 (control), 0.5, 1, and 2 mM) and cryopreserved. Sperm quality was evaluated post-thawing: motility characteristics (Computer-Assisted Semen Analysis), membrane functionality (HOS test), abnormal morphology, mitochondrial activity (Rhodamine 123), apoptotic status (Annexin V/Propidium iodide), malondialdehyde, and antioxidant activities (glutathione peroxidase (GPx), superoxide dismutase (SOD), and total antioxidant capacity (TAC)). The results showed that 1 mM ellagic acid-loaded liposomes improved total motility, membrane functionality, and viability comparing to 0.5 and 2 mM ellagic acid, 2 mM ellagic acid-loaded liposomes, and control group. Mitochondrial activity was significantly higher for 1 mM ellagic acid-loaded liposomes compared to the rest of the treatments, except 1 mM ellagic acid. Ellagic acid at 1 mM in both forms significantly increased GPx and TAC after freeze-thawing (no significant variation for SOD), and also yielded the lower proportion of apoptotic and dead cells. In conclusion, ellagic acid improved post-thawed sperm quality in broiler breeder roosters. The use of liposomes could further enhance the effects of ellagic acid.

Effect of different olive oil-derived antioxidants (hydroxytyrosol and 3,4-dihydroxyphenylglycol) on the quality of frozen-thawed ram sperm

The aim of the present study was to evaluate the effect of the addition of different concentrations of two olive oil-derived antioxidants, hydroxytyrosol (3,4-dihydroxyphenylethanol, HT) and 3,4-dihydroxyphenylglycol (DHPG), on ovine semen during the freezing-thawing process. Sperm was collected, pooled and diluted with commercial extenders and then divided into aliquots supplemented with different concentrations (10 μg/ml, 30 μg/ml, 50 μg/ml and 70 μg/ml) of HT, DHPG and a mixture (MIX) of both antioxidants. A control group, without antioxidant, was also prepared. Sperm motility, viability, acrosome integrity, mitochondrial membrane potential and lipid peroxidation (LPO) were assessed. The results showed that frozen-thawed ram spermatozoa exhibited lower values for motility, membrane integrity, acrosome and mitochondrial membrane potential than fresh samples (P ≤ 0.01). However, when antioxidants were added, thawed spermatozoa exhibited relatively low LPO, recording values similar to fresh spermatozoa; by contrast, the control group of frozen-thawed spermatozoa without antioxidants exhibited significantly higher LPO (P ≤ 0.01). The addition of a HT+DHPG mixture (MIX) had a negative impact on sperm membrane and acrosome integrity, suggesting that a pure antioxidant supplementation has the potential to offer superior results. In conclusion, HT and DHPG exhibited a positive effect on the frozen-thawed spermatozoa inasmuch as they reduced the LPO. These olive oil-derived antioxidants have the potential to improve frozen-thawed sperm quality, although further studies should be carried out to analyse the antioxidant effect at different times after thawing.

Comparison Between an Animal-Derived Product Medium and a Chemically Defined Medium for Ram Sperm Cryopreservation

Animal-derived products are widely used in sperm cryopreservation for their cryoprotective properties. These components, however, tend to be replaced because of sanitary risks. STEMALPHA.CRYO3 (Ref. 5617; Stem Alpha, Saint-Genis-l'Argentière, France), called "CRYO3," is a chemically defined preservation medium currently used for freezing human tissue and adult stem cells. The aim of this study was to evaluate the effect of a CRYO3-based medium on ram sperm freezing regarding in vitro parameters and in vivo fertility. Semen from nine Charolais rams was collected using an artificial vagina, then split and frozen using two media: a CRYO3-based medium or a control medium containing egg yolk (10%) and milk (45%). Sperm membrane integrity (propidium iodide [PI]/SYBR-14 and calcein AM/ethidium homodimer-1), acrosome integrity (FITC-PNA/PI), and mitochondrial membrane potential (JC-1) were assessed using flow cytometry, while functional membrane integrity was assessed using a hypo-osmotic swelling test and motility parameters, evaluated by computer-assisted sperm analysis. Pregnancy rates, prolificacy, and the average daily weight gain (DWG) of lambs were evaluated after performing 195 laparoscopic inseminations. The control medium showed significantly higher results than CRYO-based medium for all in vitro parameters, except for linearity and straightness (motions parameters). Conversely, field trials showed no significant difference between the control medium and the CRYO3-based medium for pregnancy rates (72.2% and 67.9%, respectively), prolificacy (1.8 and 1.6, respectively), and the DWG (0.34 and 0.35 kg/d, respectively). This preliminary study showed that CRYO3 cannot replace egg yolk and milk in freezing extenders for commercial purposes. However, as laparoscopic inseminations allowed a 67% pregnancy rate, CRYO3-based medium remains an option for international transport or long-term storage of genetic diversity.

Sperm cryopreservation: A review on current molecular cryobiology and advanced approaches

The cryopreservation of spermatozoa was introduced in the 1960s as a route to fertility preservation. Despite the extensive progress that has been made in this field, the biological and biochemical mechanisms involved in cryopreservation have not been thoroughly elucidated to date. Various factors during the freezing process, including sudden temperature changes, ice formation and osmotic stress, have been proposed as reasons for poor sperm quality post-thaw. Little is known regarding the new aspects of sperm cryobiology, such as epigenetic and proteomic modulation of sperm and trans-generational effects of sperm freezing. This article reviews recent reports on molecular and cellular modifications of spermatozoa during cryopreservation in order to collate the existing understanding in this field. The aim is to discuss current freezing techniques and novel strategies that have been developed for sperm protection against cryo-damage, as well as evaluating the probable effects of sperm freezing on offspring health.

Cysteine protects rabbit spermatozoa against reactive oxygen species-induced damages

The process of cryopreservation results in over-production of reactive oxygen species, which is extremely detrimental to spermatozoa. The aim of this study was to investigate whether addition of cysteine to freezing extender would facilitate the cryosurvival of rabbit spermatozoa, and if so, how cysteine protects spermatozoa from cryodamages. Freshly ejaculated semen was diluted with Tris-citrate-glucose extender supplemented with different concentrations of cysteine. The motility, intact acrosomes, membrane integrity, mitochondrial potentials, 8-hydroxyguanosine level and sperm-zona pellucida binding capacity were examined. Furthermore, glutathione peroxidase (GPx) activity, glutathione content (GSH), and level of reactive oxygen species (ROS) and hydrogen peroxide of spermatozoa were analyzed. The values of motility, intact acrosomes, membrane integrity, mitochondrial potentials and sperm-zona pellucida binding capacity of the frozen-thawed spermatozoa in the treatment of cysteine were significantly higher than those of the control. Addition of cysteine to extenders improved the GPx activity and GSH content of spermatozoa, while lowered the ROS, DNA oxidative alterations and lipid peroxidation level, which makes spermatozoa avoid ROS to attack DNA, the plasma membrane and mitochondria. In conclusion, cysteine protects spermatozoa against ROS-induced damages during cryopreservation and post-thaw incubation. Addition of cysteine is recommended to facilitate the improvement of semen preservation for the rabbit breeding industry.

Effect of green tea (Camellia sinensis) extract and pre-freezing equilibration time on the post-thawing quality of ram semen cryopreserved in a soybean lecithin-based extender

The aim of this study was to determine the effect of Camellia sinensis extract as antioxidant supplement and pre-freezing equilibration times in a soybean lecithin extender for freezing ram semen. In this study, a total of 20 ejaculates were collected from four Ghezel rams and diluted with extenders (1.5% soybean lecithin, 7% glycerol) containing no supplements (control) and Camellia sinensis extract (5, 10, and 15 mg/L) and cryopreserved, immediately after thermal equilibrium was reached at 5 °C (0 h), or 4 h after equilibration. Sperm motility characteristics, membrane integrity, abnormal morphology, mitochondria activity, apoptotic status, MDA and antioxidant activities (GPx, SOD and total antioxidant capacity (TAC)) were evaluated following freeze-thawing. Camellia sinensis extract at level 10 mg/L led to the highest total and progressive motilities percentages, in comparison to other treatments (P < 0.05). Our results showed that Camellia sinensis extract at level of 5 and 10 mg/L led to higher plasma membrane integrity, mitochondria activity and Total antioxidant capacity (TAC) in comparison to the level of 15 mg/L and control group (P < 0.05). Camellia sinensis extract at 10 mg/L level produced the highest percentage of live spermatozoa and the lowest apoptotic spermatozoa in comparison to all treatments (P < 0.05). In addition, level of MDA formation significantly decreased at this concentration, 10 mg/L, compared to all treatments (P < 0.05). No differences (P > 0.05) were observed between equilibration times (0 h vs. 4 h) for sperm samples incubated with or without different concentrations of Camellia sinensis extract. In conclusion, addition of Camellia sinensis extract at level of 10 mg/L can improve post-thawing quality of ram semen cryopreserved in a soybean lecithin extender. However, further research is needed to standardize the process of Camellia sinensis extraction and specially for identifying which compounds are responsible of its beneficial effect on ram sperm cryopreservation.

Fertility response of artificial insemination methods in sheep with fresh and frozen-thawed semen

The aim of this study was to evaluate the fertility response of artificial insemination (AI) methods with fresh and frozen sperm in sheep. In experiment 1, one hundred and fifty fat tailed Zandi ewes were assigned into 3 equal groups and inseminated with three AI methods consisting of vaginal, laparoscopic and trans-cervical AI with fresh semen. In experiment 2, a factorial study (3 AI methods × 2 extenders) was used to analyze the effects of three AI methods and two freezing extenders containing soybean lecithin (SL) or Egg yolk (EY) on reproductive performance of 300 fat tailed Zandi ewes. Also, total motility, progressive motility, viability and lipid peroxidation of semen were evaluated after freeze-thawing in two extenders. In result, there was no significant difference among three AI methods when fresh semen was used. In experiment 2, the highest percentage of pregnancy rate, parturition rate and lambing rate were obtained in laparoscopic AI group (P < 0.05). Although pregnancy rate, parturition rate and lambing rate in trans-cervical group were higher (P < 0.05) than vaginal group, the results were not as high as laparoscopic group. No difference was observed between SL and EY extenders and their performance was close to each other. It can be concluded that although no difference was observed on reproductive performance for fresh semen, trans-cervical AI was more efficient than vaginal method when frozen-thawed semen was used, but its efficiency was not as high as laparoscopic method. Also, SL extender can be an efficient alternative extender to preserve ram sperm during cryopreservation procedure without adverse effects of EY.

Fertility and flow cytometry study of frozen-thawed sperm in cryopreservation medium supplemented with soybean lecithin

Semen cryopreservation can provide genetic resources for a large number of females from a small number of superior males. Optimization of cryopreservation media to achieve the highest quality of post-thaw semen is crucial. Soybean lecithin has evaluated as a plant-based cryoprotectant for substitution of egg yolk in ram semen extender. Flow cytometric and fertility assessments were applied following cryopreservation procedure in two experimental groups (SL group: extender containing 1% w/v soybean lecithin and EY group: extender containing 20% v/v egg yolk). The higher percentage of live sperm and the lower percentage of dead sperm were obtained in SL (47.66 ± 1.38, 52.33 ± 1.69, respectively) extender compared to EY (41.16 ± 1.38, 58.83 ± 1.69). For motion characteristics, plasma membrane integrity, acrosome integrity and mitochondria activity, no significant difference was observed between SL and EY extenders. In artificial insemination experiment, there was no significant difference in pregnancy rate, lambing rate and twining rate between SL and EY extenders. It can be concluded that SL extender can be an efficient alternative extender to preserve ram sperm during cryopreservation procedure without adverse effects.

Cryopreservation of ram semen with antioxidant supplemented soybean lecithin-based extenders and impacts on incubation resilience

The scope of this study was investigation the affects of various antioxidants on 1% soybean lecithin-based semen extenders for ram semen cryopreservation. Ejaculates, collected via electrically stimulated ejaculation, that have a thick consistency, rapid wave motion (3-5 on a 0-5 scale) and >75% initial motility were pooled. The pooled samples were split into four equal aliquots as 5 mM Methionine, 5 mM Cysteamine, 1 mM Cysteine and a sample of antioxidant-free control group. Each sample group was diluted to a ratio of 1/5 (semen/extender, v/v) as final concentration and two step dilution method was used for cryopreservation. Extender groups were assessed for sperm motility, plasma membrane functional integrity using hypoosmotic swelling test (HOST), damaged acrosome using FITC-Pisum sativum agglutinin (PSA-FITC) and DNA integrity using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Semen samples also incubated for 6 h in humidified air with 5% CO2 at 39 °C to evaluate post-thaw incubation resilience of semen characteristics. The results showed that freezing and thawing procedures had negative effects on motility (P < 0.05), plasma membrane integrity (P < 0.05) and acrosomal integrity (P < 0.05). After 6 h of incubation time, the Cysteine supplemented extender group yielded significantly higher results than other extender groups in terms of spermatological parameters. Furthermore MDA levels in the antioxidant groups were lower than control group (P < 0.05). Nevertheless, there were no significant differences among antioxidant groups.