Freeze–thaw induced genotoxicity in buffalo (Bubalus bubalis) spermatozoa in relation to total antioxidant status

The effects of green synthesized anionic cupric oxide nanoparticles on Zaraibi goat spermatozoa during cryopreservation with and without removal of seminal plasma

Sperm motility, normal morphology, viability, spermatozoa DNA damage, and lipid peroxidation are all affected by semen cryopreservation. The goal of this study was to see how effective cupric oxide nanoparticles (CuONPs) are as a cryo-extender additive on post-thawed sperm parameters. An artificial vagina was used to collect semen samples from five mature Zaraibi bucks (2-3 years). Ejaculates were pooled and separated into two fractions (A&B), a fraction (A) was left without being centrifuged and a fraction (B) was centrifuged to remove seminal plasma. Both fractions were diluted with tris egg yolk citrate extender (TECE) and then divided into five equal aliquots, each supplemented with (0, 10, 20, 40, and 60 ppm/ml) CuONPs. The findings revealed that removing seminal plasma before cryopreservation harms sperm parameters. Sperm motility, viability index, membrane integrity, biochemical antioxidant marker, DNA integrity, and MDA level improved after supplementation with CuONPs up to 60 ppm/ml, the most prominent significant positive effect was obtained with the highest dose (60 ppm/ml) without removal of the seminal plasm compared to control group. In conclusion: The presence of seminal plasma with a high concentration of CuONPs (up to 60 ppm/ml) may help to mitigate the negative effects of cryo-preservation.

Sulforaphane inclusion in a freezing medium augments post-thaw motility, functional and biochemical features, and fertility potential of buffalo (Bubalus bubalis) spermatozoa

Sulforaphane is a natural and highly effective antioxidant safeguarding the reproductive system, and alleviate oxidative stress. This study was designed in order to elaborate L-sulforaphane effect on semen quality, biochemical parameters, and fertility of buffalo (Bubalus bubalis) spermatozoa. Semen was collected from five buffalo bull with artificial vagina (42 °C) three times and evaluated for volume, consistency (color), motility, and sperm concentration. After critical examination, semen was diluted (50 × 10⁶ spermatozoa per ml, 37 °C) in extenders with (2 μM, 5 μM, 10 μM, and, 20 μM) or without (control) sulforaphane, cooled (from 37 to 4 °C), equilibrated (4 °C), filled (straws, 4 °C), and cryopreserved (LN₂, -196 °C). Data analysis exhibited that sulforaphane addition in extender augments total motility (%, 10 μM, and 20 μM than control), progressive motility (%), and rapid velocity (%, 20 μM than control), and velocity parameters (average path velocity, μm/s, straight line velocity, μm/s and curved linear velocity, μm/s, 20 μM than control, and 2 μM). Moreover, sulforaphane augments functional features (membrane functionality, mitochondrial potential, and acrosome integrity) of buffalo sperm (20 μM than control). Sulforaphane preserves biochemical features of seminal plasma of buffalo i.e., Calcium (μM), and total antioxidant capacity (μM/L), followed by reduction in lactate dehydrogenase (IU/L), reactive oxygen species (10⁴ RLU/20 min/ 25 million), and lipid peroxidation (μM/ml) in 20 μM than control. Lastly, sulforaphane augments fertility rate of buffalo sperm at 20 μM than control, and 2 μM. Conclusively the existing study revealed that adding L-sulforaphane (20 μM) in a freezing medium augments motilities, kinematics, functional parameters, and fertility rate of buffalo spermatozoa. Correspondingly, sperm favorable biochemical features were also augmented with sulforaphane followed by reduction in oxidative stress parameters. Further studies are highly recommended to define the particular mechanism of action of sulforaphane in augmenting buffalo post-thawed semen quality, and in vitro fertility potential.

Effect of Different Concentrations of Melatonin on Ram Epididymal Spermatozoa Recovered Post-mortem under Oxidative Stress Conditions and Storage at 4 °C

The current study examines the protective effects of different melatonin concentrations on fresh ram epididymis spermatozoa after post-mortem recovery under normal and oxidative stress conditions and during liquid preservation (4^o C) at different times (24, 48, and 72h). The testes were obtained from a local slaughterhouse during the breeding season. Spermatozoa were isolated from cauda epididymidis. In experiment 1, the effects of adding different concentrations of melatonin (0, 15, 60, and 240 μg/mL) under normal and oxidative stress conditions were evaluated. Fifty μM of hydrogen peroxide was used to induce oxidative stress. Also, in experiment 2, the spermatozoa samples were chilled to 4^o C and stored for 72 h. Sperm total motility, viability, membrane, DNA integrity, and morphological abnormality were evaluated at 0, 24, 48, and 72 h after cooling storage. In experiment 1, melatonin treatment preserved viability increased TAC and SOD activities, and reduced MDA levels compared to control. Also, melatonin reduced the harmful effects of H2O2 under induced oxidative stress. In experiment 2, Melatonin at concentrations of 15 and 60 g/mL greatly increased sperm viability after 3 days of cold storage. Furthermore, it could have a significant protective effect on the motility of cooled sperm. Melatonin supplementation preserved higher sperm membrane integrity at concentrations of 15 and 60μg/mL, DNA integrity at a concentration of 15μg/mL, and abnormality at a concentration of 60μg/mL after 3 days of storage. The results suggest that melatonin can be used to reduce the adverse effects of induced oxidative stress in spermatozoa. Furthermore, ram epididymal spermatozoa could be stored at 4 °C for 72 h when treated with melatonin.

Supplementation of Mito TEMPO and acetovanillone in semen extender improves freezability of buffalo spermatozoa

BACKGROUND

Oxidative stress is one of the leading factors responsible for poor post-thaw semen quality because of overproduction of reactive oxygen species (ROS) over neutralizing antioxidants present in semen. Mainly two ROS generation sites are present in spermatozoa, that is, mitochondria and plasma membrane. Therefore, the idea of targeting these specific sites for minimization of ROS production with the compounds having known mechanism of actions was built up as a core for this research.

OBJECTIVE

Present study was done to investigate the effects of Mito TEMPO and acetovanillone individually and in combination on freezability of buffalo spermatozoa.

MATERIALS AND METHODS

For the experiment, semen extender was supplemented with Mito TEMPO (50 μM), acetovanillone (50 μM), and a combination of Mito TEMPO + acetovanillone (50 μM+ 50 μM), designated as Group II, Group III, and Group IV, respectively. Control group without any supplementation was designated as Group I. A total of 24 ejaculates with individual progressive motility (IPM) of ≥70% were selected for the study. After final dilution, filling-sealing of straws, equilibration, and freezing were done as per the standard procedure. Semen samples were evaluated for IPM, plasma membrane integrity, lipid peroxidation, total antioxidant capacity (TAC), and cholesterol to phospholipids (C/P) ratio at both fresh and post-thaw stages. Evaluation of ROS, mitochondrial membrane potential (MMP), capacitation status (CTC assay), and in vitro fertility potential were conducted only on frozen-thawed samples.

RESULTS

The addition of Mito TEMPO (50 μM) and acetovanillone (50 μM) individually and in combination significantly (p < 0.05) improved post-thaw semen quality in terms of IPM, plasma membrane integrity, TAC, cholesterol content, C/P ratio, MMP, Chlortetracycline (CTC)-Full (F) pattern, and zona binding ability of buffalo spermatozoa, while significantly (p < 0.05) reduced ROS production, lipid peroxidation, and capacitation like changes as compared to the control group.

DISCUSSION

As Mito TEMPO acts as an SOD mimetic and also detoxifies ferrous iron at the mitochondria level, it aids in neutralization of excessive ROS production and minimizes oxidative stress-related damages that enhances the antioxidant potential of sperm mitochondria. Earlier studies also indicated improved post-thaw semen quality in 50 μM supplemented group. The improvement observed in acetovanillone (50 μM) group might be because of inhibition of Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase as this enzyme activation by various physical/chemical inducers during cryopreservation process leads to activation of CatSper channel resulting in calcium influx, premature capacitation, and acrosomal reaction like changes through activation of adenylate cyclase and cAMP/PKA-mediated tyrosine phosphorylation of sperm proteins. Acetovanillone also prevents NADPH oxidase-mediated inhibition of glutathione reductase activity, which has a vital role in protecting the structural and functional integrity of sperm plasma membrane.

CONCLUSION

Results indicated beneficial effects of supplementation of Mito TEMPO and acetovanillone on sperm freezability and individual supplementation was as efficient as the combination group for sustaining post-thaw semen quality.

The addition of resveratrol in tris citric acid extender ameliorates post-thaw quality parameters, antioxidant enzymes levels, and fertilizing capability of buffalo (Bubalus bubalis) bull spermatozoa

Resveratrol is a natural grape-derived polyphenol with potent antioxidant properties that protect spermatozoa against lipid peroxidation (LPO) by eradicating free radicals. The objectives of this study were to 1) appraise the effects of resveratrol in extender on post-thaw quality parameters, antioxidant enzymes, adenosine triphosphate (ATP), DNA fragmentation, LPO and 2) fertilizing capability of buffalo bull spermatozoa. Semen was collected from four fertility proven bulls with artificial vagina thrice, evaluated initially, and diluted in five different extenders containing resveratrol (T4 = 100 μM, T3 = 50 μM, T2 = 20 μM, T1 = 10 μM), and control (no resveratrol), and evaluated after post-dilution and post-thawing stage of cryopreservation. Analysis of variance revealed that, there was no difference (P > 0.05) in any parameters due to treatments at post-dilution. However, at post-thawing, sperm progressive motility (%), plasma membrane integrity (%), mitochondrial membrane potential (%) and ATP levels (nmol/10⁶) were found higher in semen samples cryopreserved in T3 and 4 than control. Sperm supravital plasma membrane integrity (%) and viable/acrosome integrity were found higher in semen samples cryopreserved in T4 than control and T1. Furthermore, sperm catalase (U/mL), glutathione peroxidase (μM) and superoxide dismutase (U/mL) concentrations were found significantly higher in resveratrol treated groups as compared to the control. Conversely, DNA fragmentation (%) and LPO (μM/mL) were significantly (P > 0.05) decreased in semen samples cryopreserved in T4 in comparison to the control. Fertilizing capability was found higher in semen samples cryopreserved in T4 as compared to the control (%, 77.33 vs. 57.41, P < 0.05). It is concluded that the addition of resveratrol in extender ameliorates quality parameters, antioxidant enzymes levels and fertilizing capability, and alleviate DNA fragmentation and LPO in buffalo spermatozoa during cryopreservation.

Supplementation of l-tryptophan (an aromatic amino acid) in tris citric acid extender enhances post-thaw progressive motility, plasmalemma, mitochondrial membrane potential, acrosome, and DNA integrities, and in vivo fertility rate of buffalo (Bubalus bubalis) bull spermatozoa

The aromatic amino acid l-tryptophan is an essential and versatile molecule, acts by transferring an electron to free radicals and protects the plasma membrane from injuries. The aim of the present study was to investigate the effects of l-tryptophan in extender on semen quality parameters, in vitro longevity and in vivo fertility rate of buffalo spermatozoa during cryopreservation. Two ejaculates were collected from each bull (n = 2 ejaculates and n = 4 bulls) with artificial vagina at 42 °C followed by initial evaluation for volume, motility, concentrations and were diluted in five extenders (C = lacking l-tryptophan, D1 = 25 μ M l-tryptophan, D2 = 50 μ M l-tryptophan, D3 = 75 μ M l-tryptophan, and D4 = 100 μ M l-tryptophan) respectively, and cryopreserved. The experiment was repeated four times (n = 4 replicates). At post-dilution, sperm plasma membrane integrity (PMI, %), supravital plasma membrane integrity (SVPMI, %), hypo-resistivity (HR, %) and acrosome integrity (ACR-I, %) were significantly higher (P < 0.05) in extender supplemented with D4 than control. At post-thawing, progressive motility (PM, %), PMI, SVPMI, HR, ACR-I, and DNA-I of buffalo bull spermatozoa were significantly higher in D4 than control. Sperm in vitro longevity (%) assessed in terms of PM, SVPMI, and ACR-1 were significantly higher in D4 than control. Sperm mitochondrial membrane potential (%) was higher in treated groups than the control. The in vivo fertility rate was significantly higher in D4 than control (60.17% vs. 44.17%, P < 0.05). It is concluded that the supplementation of l-tryptophan in tris citric acid extender improves semen quality parameters, in vitro longevity and in vivo fertility rate of buffalo spermatozoa during freezing and thawing process.

Stimulating effects of Quercetin (QUE) in tris citric acid extender on post thaw quality and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa

Aim of this study was to evaluate the stimulating effects of quercetin (QUE) on post thaw quality and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa. QUE is a well-known flavonoid having antioxidant properties to scavenge free radicals. Semen was collected from three buffalo bull through artificial vagina (42 °C) and were evaluated initially for volume, motility, concentration, followed by dilution in five extenders (n = 5 aliquots, control, C = no QUE; treatment 1, T1 = 50 μM QUE; treatment 2, T2 = 100 μM QUE; treatment 3, T3 = 150 μM QUE and treatment 4, T4 = 200 μM QUE supplementation). The experiment was repeated thrice (n = 3 replicates). At post dilution, sperm progressive motility (PM, %) plasma membrane integrity (PMI, %), supra vital plasma membrane integrity (SVPMI, %) and acrosome integrity (ACR-1, %) of buffalo bull were significantly higher (P < 0.05) in extenders supplemented with QUE than C. At thawing, sperm PM of buffalo bull was higher in T3 and T4 than C, T1 and T2. Sperm SVPMI was significantly higher in T2, T3 and T4 than C and T1. Sperm ACR-I was higher in T3 and T4 than C, T1 and T2. Sperm DNA integrity was higher in T4 than C. QUE supplementation increased in vitro semen quality during 30 and 60 min of incubation at 37 °C than C. The in vivo fertility was higher in T3 and T4 than C (%, 61.82 vs. 65.22 vs. 46.90). It is concluded that QUE @ 150 and 200 μM improved post thaw semen quality and in vivo fertility of buffalo bull.

Melatonin diminishes oxidative damage in sperm cells, improving assisted reproductive techniques

Sperm preparation procedures are a potential generator of oxidative stress-induced DNA damage, which leads to a dramatic drop in fertility. An increasing number of studies suggest that melatonin reduces the oxidative stress induced by manipulation. However, very little is known about the preservative role of melatonin in sperm preparation medium during assisted reproduction procedures. For this aim to be achieved, semen was divided into two fractions and preincubated with and without 1 mM melatonin. Afterwards, both fractions were divided into two subfractions to perform swim-up in the presence and absence of 1 mM melatonin. Labeling with anti-CD46 and antiactive caspase-3 allowed the monitoring of acrosome reaction and apoptosis by flow cytometry. Sperm DNA fragmentation and compaction were analyzed through propidium iodide staining. The normozoospermic and oligozoospermic samples that were preincubated with melatonin underwent a significant increase in the ratio of adequate spermatozoa and a reduction of caspase-3 activation. Additionally, preincubation with melatonin enhanced the migration of sperm cells with compacted DNA in oligozoospermic samples (P < 0.05) and prevented DNA fragmentation in normozoospermic samples (P < 0.05). In light of the current results, the cytoprotective capacity and innocuousness of melatonin make it a great candidate to be applied in assisted reproduction techniques in order to prevent triaogenic oxidative damage.

Evaluation of α-linolenic acid for freezability and in vivo fertility of Nili Ravi (Bubalus bubalis) buffalo semen

Alpha linolenic acid (ALA) is integral component of cell membrane that protects the cell in stressful events and involves in many metabolic pathways. It was hypothesized that ALA have the ability to protect the structural and functional integrity of buffalo spermatozoa during freeze-thawing. Therefore, study was designed to evaluate ALA supplementation (0, 5, 10 and 20 ng/mL) in extender on freezability and in vivo fertility of buffalo bull spermatozoa. Semen from three adult Nili-Ravi buffalo bulls of similar age was collected with artificial vagina (42 °C) for five weeks (replicates; N = 30). Qualified semen ejaculates (>1 mL volume, >60% motility; >0.5 billion/mL concentration) were diluted with tris-citric acid extender containing 0.0 (control), 5.0, 10.0 and 20.0 ng/mL ALA at 37 °C and cryopreserved following established protocol. Sperm motility and plasma membrane integrity were recorded higher (P < 0.05) in extender containing 5.0 ng/mL of ALA compared to control. Nevertheless, sperm viability, live dead ratio and chromatin integrity were observed higher (P < 0.05) in all experimental extenders with ALA compared to control. The number of abnormal sperm reduced significantly in all experimental extenders having ALA. A total of 539 artificial inseminations were performed with the best evolved extender having ALA (5.0 ng/mL; 272 inseminations) and control (267 inseminations). In vivo fertility rates of buffalo semen were recorded higher (P < 0.05) with extender containing ALA (5.0 ng/mL) (58%) compared to control (46%). In conclusion, supplementing 5.0 ng/mL ALA in extender improved the post-thaw quality and in vivo fertility of cryopreserved Nili-Ravi buffalo bull semen.

The effect of cholesterol loaded cyclodextrins on post-thawing quality of buffalo semen in relation to sperm DNA damage and ultrastructure

The cryopreservation of germ cells is a major tool for the propagation of animals with desired genetic traits. Although cryopreservation of spermatozoa in some animals is effective, its effectiveness is variable. For example, cryopreservation efficiency of buffalo bull spermatozoa remains very poor. In this study, we evaluated sperm DNA damage and ultrastructure in buffalo bull spermatozoa vitrified in the presence or absence of cholesterol-loaded cyclodextrins (CLC). Our results showed that cryopreserved buffalo spermatozoa had elevated levels of deteriorated plasma and mitochondrial membranes, which are the likely causes of DNA damage after vitrification. Accordingly, the levels of the activity of Alanine Aminotransferase (ALT), Alkaline phosphatase (ALP) and Aspartate Aminotransferase (AST) were also elevated following exposure of buffalo bull spermatozoa to a cycle of freezing-thawing. Importantly, supplementation of Tris-Egg Yolk-Glucose (TEYG) extender with (CLC) improved the quality of buffalo spermatozoa following cryopreservation. This protective effect of CLC is likely due to decreasing mitochondrial and plasma membrane deterioration with subsequent inhibition of DNA damage. These results suggest that cholesterol loss is the likely reason for poor semen quality in buffaloes following cryopreservation, and provide evidence that manipulating lipid content during cryopreservation is a promising strategy to improve the quality of buffalo semen.

Identification of suitable combinations of in vitro sperm-function test for the prediction of fertility in buffalo bull

The present study assessed sperm functional characteristics in the frozen-thawed semen of buffalo bulls and estimated their relationship with field fertility. Frozen semen samples from three different freezing operations each from nine Murrah buffalo bulls were used for the assessment of different sperm functions related to fertilizing potential. Bulls were classified into high (n = 2), medium (n = 5), and low (n = 2) fertile based on adjusted field fertility. The sperm functions estimated included membrane integrity using carboxyfluorescein diacetate-propidium iodide, acrosome reaction status using fluorescein isothiocyanate peanut agglutinine, status of apoptosis using Annexin-V, protamine deficiency using Chromomycin A₃, membrane stability using Merocyanine 540 and lipid peroxidation status using 4, 4-difluoro-4-bora-3a, 4a-diaza-s-indacene. The relationship between the proportion of live acrosome-intact spermatozoa and fertility was positive and significant (r = 0.59; P = 0.001). The proportion of moribund spermatozoa showed a significantly negative correlation with fertility (r = -0.50; P = 0.008). Similarly, the relationship of spermatozoa with unstable membrane (r = -0.51; P = 0.007), necrotic (r = - 0.42; P = 0.028), early necrotic (r = -0.42; P = 0.031), and apoptotic spermatozoa (r = -0.39; P = 0.046) with bull fertility was negative and significant. The correlation between the protamine-deficient spermatozoa and fertility was negative, but not significant. Among different combinations of tests, live acrosome-intact spermatozoa and lipid peroxidation status of spermatozoa revealed high positive correlation with buffalo bull fertility (adjusted R² = 0.73, C[p] = 0.80). These preliminary findings may help in developing tools for assessing fertility of buffalo bulls, once validated in more animals.

Effect of glutamine supplementation and replacement of tris-egg yolk based extender with defatted cow milk on spermatozoa quality after equilibration and thawing

AIM

The present study was designed to evaluate the effect of supplementation of glutamine and replacement of Tris-egg yolk (TE) based buffer with defatted cow milk on the spermatozoa quality after equilibration and thawing.

MATERIALS AND METHODS

Semen was collected from five Bhadawari bulls biweekly, and a total of 30 ejaculates were taken. The semen ejaculates were pooled and divided into three equal parts. The pooled semen was diluted by TE based extender (control), TE + glutamine (8 mM) (T1) and 50% TE + 50% deffated cow milk + glutamine (8 mM) (T2). At two stages viz. after equilibration and after 12 h of cryopreservation (thawed samples), progressive motility, percent live, and percent acrosomal damage of the spermatozoa was assessed.

RESULTS

Supplementation of glutamine improved (p<0.05) the spermatozoa quality with respect to the progressive motility, percent live and acrosomal damage both post-equilibration and post-thaw. T2 improved (p<0.05) the spermatozoa quality as compared to control, however; it was less (p<0.05) effective as compared T1 both post-equilibration and post-thaw.

CONCLUSION

From the results of present study it can be concluded that glutamine supplementation was effective in maintaining post-equilibration and post-thaw spermatozoa quality whereas defatted cow milk was not as effective as TE based buffer in the extender in improving the spermatozoa quality.

Effect of Superoxide Dismutase on Semen Parameters and Antioxidant Enzyme Activities of Liquid Stored (5°C) Mithun (Bos frontalis) Semen

The present study was undertaken to assess the effect of superoxide dismutase (SOD) on sperm motility, and viability; total sperm abnormality; acrosomal and plasma membrane integrity; DNA abnormality; antioxidant profiles such as catalase (CAT), reduced glutathione (GSH), and total antioxidant capacity (TAC); enzymatic profiles such as aspartate amino transaminase (AST), and alanine amino transaminase (ALT); and biochemical profiles such as malondialdehyde (MDA) production and cholesterol efflux. Total numbers of 50 ejaculates were collected twice a week from eight mithun bulls and semen was split into four equal aliquots, diluted with the TEYC extender. Group 1: semen without additives (control), and group 2 to group 4: semen was diluted with 50 U/mL, 100 U/mL, and 150 U/mL of SOD, respectively. These seminal parameters, antioxidant, enzymatic, and biochemical profiles were assessed at 5°C for 1, 6, 12, 24, and 30 h of incubation. Inclusion of SOD into diluent resulted in significant (P<0.05) decrease in percentages of dead spermatozoa, abnormal spermatozoa, and acrosomal abnormalities at different hours of storage periods as compared with control group. Additionally, SOD at 100 U/mL has significant improvement in quality of mithun semen than SOD at 50 or 150 U/mL stored in in-vitro for up to 30 h. It was concluded that the possible protective effects of SOD on sperm parameters are that it prevents MDA production and preserves the antioxidants and intracellular enzymes during preservation.

Arachidic acid in extender improves post-thaw parameters of cryopreserved Nili-Ravi buffalo bull semen

Cryopreservation process reduces lipids and phospholipids from buffalo bull spermatozoa. It was therefore hypothesized that supplementation of fatty acid to extender may improve the post-thaw quality of buffalo semen. The objective was to evaluate the effect of arachidic acid supplementation in extender on post-thaw quality of buffalo bull (Bubalus bubalis) spermatozoa. Semen was collected from three adult Nili-Ravi buffalo bulls of similar age group with artificial vagina (42°C) for 3 weeks (replicate). Qualified semen ejaculates (n = 18) were split into four aliquots and diluted in tris-citric acid extender containing 0.0 (control), 5.0, 10.0 and 20.0 ng/ml at 37°C having approximately 50 × 10(6) spermatozoa/ml. Diluted semen was cooled to 4°C in 2 h and equilibrated for 4 h at 4°C. Cooled semen was filled in 0.5-ml straws at 4°C, kept on liquid nitrogen vapours for 10 min and plunged in liquid nitrogen for storage. Thawing of frozen semen was performed after 24 h at 37°C for 30 s. Sperm progressive motility (%) was improved in a dose-dependent manner by supplementing arachidic acid at 5.0, 10.0 and 20.0 ng/ml compared with control. Structural and functional integrity of sperm plasma membrane (%), number of acrosome-intact live sperm (%) and sperm chromatin integrity (%) were better (p < 0.05) in extender having 5.0 ng/ml of arachidic acid compared with control. At 10.0 ng/ml, these values did not vary (p > 0.05) from those at 5.0 ng/ml. Further improvement in structural and functional integrity of sperm plasma membrane, number of acrosome-intact live sperm and chromatin integrity was observed at 20.0 ng/ml of arachidic acid in extender. In conclusion, arachidic acid supplementation in extender improved the post-thaw quality parameters of cryopreserved Nili-Ravi buffalo bull spermatozoa. Among the arachidic acid concentrations studied, maximum improvement in post-thaw semen quality parameters was observed at 20.0 ng/ml.

Glutathione-supplemented tris-citric acid extender improves the post-thaw quality and in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa

In this study we evaluated the effects of semen extender supplementation with different concentrations of glutathione (GSH) on buffalo (Bubalus bubalis) bull sperm motility, plasma membrane integrity, viability and DNA integrity as well as in vivo fertility. Semen from three Nili-Ravi buffalo bulls was collected, and qualified semen ejaculates (n=18) were split into five aliquots for dilution (37°C; 50×10(6)spermatozoaml(-1)) with experimental tris-citric acid extender containing 0, 0.5, 1.0, 1.5 or 2.0 mM GSH. Extended semen was cooled to 4°C, equilibrated and filled in French straws. The straws were kept on liquid nitrogen vapors (5 cm above the LN(2) level) for 10 min and plunged in liquid nitrogen for storage. Sperm motility (%), plasma membrane integrity (%), viability (%) and DNA integrity (%) were assessed at 0, 2 and 4h post-thawing (37°C). Extender supplementation with GSH (0.5, 1.0, 1.5 and 2.0 mM) increased sperm motility, plasma membrane integrity and viability in a dose dependent manner. Sperm DNA integrity was higher (p<0.05) in all experimental extenders containing GSH when compared to the control extender (0 mM GSH). The in vivo fertility rate of cryopreserved buffalo bull (n=2) spermatozoa was higher (p<0.05) in extender containing 2.0 mM GSH compared to that of control. In summary, tris-citric acid extender supplemented with glutathione improved the freezability of buffalo bull spermatozoa in a dose dependant manner. Moreover, the addition of 2.0 mM GSH to the extender enhanced the in vivo fertility of buffalo (Bubalus bubalis) bull spermatozoa.