l-Cysteine improves antioxidant enzyme activity, post-thaw quality and fertility of Nili-Ravi buffalo (Bubalus bubalis) bull spermatozoa

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.

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.

Cysteine supplementation pre-freeze and post-thaw improves integrity and reduces oxidative stress in cryopreserved ram spermatozoa

Cryopreserved ram sperm is highly sensitive to oxidative stress by reactive oxygen species (ROS) which impair sperm function and integrity. Antioxidants such as cysteine can mitigate the effect of ROS, although the optimal concentration or timing of supplementation is unknown. This study aimed to determine the effect of concentration and timing of cysteine supplementation on the integrity and function of cryopreserved ram spermatozoa. Nine ejaculates were collected from three Texel rams then cryopreserved and supplemented with cysteine (0, 0.5, or 1.0 mg/mL) added pre-freeze (PF), post-thaw (PT) or pre-freeze and post-thaw (PF + PT) generating seven treatments: 1) control 0 mg/mL, 2) PF 0.5 mg/mL, 3) PF 1 mg/mL, 4) PT 0.5 mg/mL, 5), PT 1.0 mg/mL, 6) PF + PT 0.5 mg/mL and 7) PF + PT 1.0 mg/mL. Sperm motility, viability, acrosome integrity, ROS production and penetrability through artificial cervical mucus were assessed post-thaw. Cysteine supplementation reduced ROS production which thereby improved spermatozoa motility, viability, acrosome integrity and penetrability (p < 0.001) Sperm integrity for all parameters was greatest in spermatozoa treated PF + PT with 1.0 mg/mL cysteine, although treatment pre-freeze or post-thaw also improved integrity beyond the control. This study has identified that 1.0 mg/mL cysteine is most beneficial and has highlighted the importance of preventing oxidative stress in spermatozoa post-thaw. These finding can help to mitigate the detrimental effect of cryopreservation on spermatozoa and aid the development of cryopreservation protocols in sheep.

Ameliorative effect of crocin on post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo (Bubalus bubalis) bull sperm

Buffalo bull sperm suffer more cryoinjuries due to lipid peroxidation of high structural polyunsaturated fatty acid contents than cattle sperm. Consequently, the post-thaw fertilization potential of buffalo bull sperm is compromised. Crocin is a carotenoid known for its antioxidant potential through scavenging reactive oxygen species. Objectives of the current study were to investigate the effect of crocin addition in the semen extender on post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo bull sperm. Semen samples (n = 32) from four Nili-Ravi buffalo bulls were extended with tris-citric acid extender containing different concentrations of crocin (0 mM; control, 0.5, 1, 1.5 and 2 mM). The extended semen was packed in 0.5 mL French straws (25 × 106 sperm/straw) and cryopreserved in liquid nitrogen. Computer-assisted semen analysis, hypo-osmotic swelling test, normal apical ridge assay, Rhodamine 123, acridine orange, propidium iodide staining, and thiobarbituric acid reactive substances assay were performed to assess sperm motility parameters, plasma membrane integrity, acrosome integrity, mitochondrial membrane potential, DNA integrity, viability, and lipid peroxidation, respectively. Expression levels of sperm acrosome-associated SPACA3, DNA condensation-related PRM1, anti-apoptotic BCL2, pro-apoptotic BAX, and oxidative stress-associated ROMO1 genes were evaluated through qPCR. The fertility of semen doses containing the most potent concentration of crocin (based on optimum post-thaw semen quality) was compared with control during the breeding season. Buffaloes (n = 400; 200/group) were inseminated 24 h after the onset of oestrus and transrectally palpated for pregnancy at least 60 days post-insemination. Results revealed that 0.5 and 1 mM crocin improved sperm post-thaw total motility, plasma membrane integrity, acrosome integrity, mitochondrial membrane potential and viability, and 1 and 1.5 mM crocin enhanced catalase activity and reduced lipid peroxidation compared to control (p < .05). Moreover, 1 mM crocin improved sperm post-thaw progressive motility, kinematics, and DNA integrity, and 1.5 mM crocin enhanced plasma membrane integrity than control (p < .05). Expression levels of SPACA3, PRM1 and BCL2 genes were higher (p < .05) with 1 mM crocin compared to other groups. In contrast, no difference (p > .05) was noticed in expressions of BAX and ROMO1 genes among all groups. The fertility rate of semen doses containing the most potent concentration (1 mM) of crocin was higher (p = .0465) compared to control (56 ± 0.03% vs. 46 ± 0.04%, respectively). In conclusion, 1 mM crocin in the semen extender improves post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo bull sperm.

Effects of supplementation of cryopreservation media with cysteine on the post-thaw quality and fertility of brown-marbled grouper (Epinephelus fuscoguttatus) spermatozoa

The cryopreservation process is associated with the generation of excessive reactive oxygen species, which causes a series of cellular damage to spermatozoa. The objective of the current study was to investigate the effect of different concentrations of cysteine on post-thaw sperm quality of brown-marbled grouper sperm. Semen samples were frozen with cysteine supplemented at 0.5, 1, 2, 5, 10 mM and the control group (no additive). After thawing, sperm quality parameters were analyzed. In comparison to the control, cysteine treatment groups yielded relatively higher sperm total motility, progressive motility, and curvilinear velocity. Different concentrations of cysteine had no effect on average path velocity, straight linear velocity and viability (P > 0.05), while an increase in the concentration of cysteine resulted in a significant improvement in the mitochondrial membrane potential, SOD activity, and ATP content (P < 0.05). As for lipid peroxidation, the extent of which in cysteine treated spermatozoa was less than the control, although the differences were not statistically significant (P > 0.05). In terms of fertilizing capacity, a greater hatching rate (91.7 ± 1.2%) was obtained in thawed sperm treated with 2 mM cysteine, compared to the control (84.3 ± 4.2%; P < 0.05). Overall, it is concluded that the addition of cysteine is helpful in maintaining the function of frozen-thawed brown-marbled grouper sperm, which can be recommended as an effective antioxidant to improve the semen cryopreservation efficiency.

Reducing oxidative stress by κ-carrageenan and C60HyFn: The post-thaw quality and antioxidant status of Azari water buffalo bull semen

Azeri water buffalo is a species of great interest due to the high quality of its products such as milk. Due to the decreasing trend of its number and risk of extinction in the future, our attention is directed towards ensuring the preservation of its genetic reserves by keeping its sperm. Using antioxidants in semen extender is one of the ways to reduce the detrimental effects of freezing process on post-thawed quality of spermatozoa. This study was conducted to determine the effect of κ-carrageenan (k-CRG) and C60HyFn supplemented semen extender on the quality of post-thawed Azari water buffalo spermatozoa. A total of 30 semen samples were obtained from three buffaloes using an artificial vagina (twice a week for five weeks = 10 replicates). The samples (n = 3) from each replicate were pooled and divided into equal aliquots to prepare 14 extender groups, including control (C), k-0.2, K-0.4, K-0.6, K-0.8 (containing 0.2, 0.4, 0.8 mg K-CRG/mL, respectively), C-0.1, C-0.2, C-0.4, C-0.8, C-1, C-5, C-10, C-20, and C-40 (containing 0.1, 0.2, 0.4, 0.6, 0.8, 1, 5, 10, 20, 40 μM C60HyFn, respectively), and then frozen. After thawing, motility and velocity parameters, plasma membrane integrity (PMI) and functionality (PMF), DNA damage, Hypo-osmotic swelling (HOS) test, malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase glutathione activities and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging were evaluated. In vivo fertility was compared between k-0.6, C-1 and control groups. 60 buffalo were inseminated 24 h after the onset of estrus. The diagnosis of pregnancy was performed rectally at least 60 days after fertilization. Total and progressive motility and velocity parameters were improved by k-0.4, k-0.6, k-0.8, C-0.4, C-0.8, C-1, C-5, and C-10 groups) compared to the other groups. Plasma membranes integrity and PMF were improved by k-0.4, k-0.6, C-0.4, C-0.8, C-1, C-5, and C-10 groups compared to other groups, while in terms of sperm DNA damage K-0.4, K-0.6, K-0.8, C-0.2, C-0.4, C-0.8, C-1, C-5, and C-10 groups showed better results compared to the control group. The evidence also showed that k- 0.4, k-0.6, k-0.8, C-0.4, C-0.8, C-1, C-5, and C-10 groups could improve TAC, and decrease MDA levels. Also, k-0.4, k-0.6, k-0.8, C-0.2, C-0.4, C-0.8, C-1, C-5, and C-10 groups could improve GPx, CAT, and GSH levels, but no significant difference was found regarding SOD compared to the other groups. DPPH scavengers were tested by K-0.6, K-0.8 and C-1, C-5, C-10, C-0.8, C-0.4 and C-0.2 groups and compared to other groups improved. The fertility rate [70% (14/20)] was higher in C-1 than other groups. To conclude that k-CRG and C60HyFn supplementation can increase the quality parameters of cryopreserved buffalo semen after thawing and that 1 M C60HyFn can increase in vivo fertility of buffalo semen.

Effect of supplementing L-cysteine and its group analogs on frozen semen quality of bulls: A meta-analysis

Background and Aim

The quality of frozen bull sperm after thawing is influenced by the primary diluent and antioxidant. This meta-analysis was conducted to determine the effect of supplementing L-cysteine and its group analogs on the quality of frozen bull sperm.

Materials and Methods

A total of 22 articles obtained from Google Scholar and Scopus were integrated into metadata. The effects of adding L-cysteine and its analogs (e.g., cysteine HCl and N-acetyl-L-cysteine), both of which are known as L-cysteine, were evaluated in this meta-analysis. The following parameters were examined: Abnormality, acrosome damage, acrosomal integrity, DNA damage, DNA integrity, malondialdehyde (MDA) content, plasma membrane integrity, pregnancy rate, progressive motility, sperm viability, and total motility. Data were analyzed using the mixed model methodology, with L-cysteine dosage as a fixed effect and different studies as random effects.

Results

L-cysteine supplementation significantly increased the total motility (p < 0.05) and MDA content of semen, following a linear pattern. Progressive motility, acrosomal integrity, and plasma membrane integrity were significantly increased, showing a quadratic pattern (p < 0.05). Abnormality and acrosome damage were significantly decreased (p < 0.05), following a quadratic and linear pattern, respectively. Other parameters remained unaffected by L-cysteine supplementation. L-cysteine and cysteine HCl significantly inhibited (p = 0.001) acrosome damage in thawed frozen sperm compared with control sperm.

Conclusion

Supplementing L-cysteine and its analog groups are recommended for freezing bull semen as it generally improves sperm quality.

Use of Purslane (Portulaca oleracea) Extracts and Cysteine in Diluents to Improve the Cryopreserved Quality of Goat Sperm

Highlights Using cysteine and purslane extracts in extenders improved significantly the post-thaw sperm characteristics. Sperm viability, DNA integrity, and mitochondrial activity demonstrate an improvement in post-thaw sperm. Malondialdehyde production was decreased based on the positive effects of treated extenders. The obtained results demonstrate that supplementation of 50 μg/mL of purslane methanolic extract with cysteine to freezing extenders was significantly superior compared with other treatments.

Antioxidant effect of Moringa olifera leaves extract in extender improves post-thaw quality, kinematics, lipid peroxidation, total antioxidant capacity and fertility of water buffalo bull semen

Our objectives were to determine the antioxidant effect of Moringa olifera leave extract (MLE) in tris extender on post-thaw quality, kinematics, lipid peroxidation, total antioxidant capacity and field fertility of water buffalo bull semen. Semen was collected on a weekly basis for 5 weeks (n = 5 bulls & n = 25). After collection, every sample was diluted individually with extender (tris egg yolk) containing MLE concentrations (0%, 5%, 10%, 15% and 20%) at 37°C. After dilution, semen was filled in 0.54 mL straws and frozen in automatic freezer. After thawing, sperm motility (%) (progressive & total), path velocity (µm/s), straight velocity (µm/s), curvilinear velocity (%), beat cross frequency (Hz), linearity (%), straightness (%), length of average path (µm), length of straight-line path (µm), length of curvilinear path (µm), plasma membrane integrity (%), acrosome membrane integrity (%), DNA integrity (%) and morphology (%) were higher (p < 0.05) in spermatozoa preserved in extender containing 15% MLE as compared to control. The fertility rate (60%, vs. 45%) was higher (p < 0.05) with semen doses frozen with 15% MLE in extender than the control. In conclusion, 15% MLE improves semen quality, kinematics and field fertility in water buffaloes.

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.

Effects of Selenium on Bull’s Sperm Oxidative Stress and Viability Under in Vitro Conditions

The aim of this study was to determine the effects of sodium selenite on the level of oxidative stress and viability of spermatozoa in fresh bull ejaculate in in vitro conditions at different temperatures. Samples of the bull's ejaculates with a concentration of 7 × 105 spermatozoa per ml were placed into the commercial semen extender containing 0 (control), 1 (1Se), 3 (3Se) and 5 (5Se) µg.ml–1 of sodium selenite. The following analyses were performed by flow cytometry after 1, 3, 6, 8, 24, 48 and 72 hours of incubation at 4 °C and 37 °C. All analyses were carried out in triplicate. The level of oxidative stress at both temperatures were significantly lower in the experimental groups in comparison to the control group. However, a significant decline of live sperm concentration and a rise of damaged sperm concentration were recorded, especially in groups 1Se and 3Se in comparison to the control group. Only in group 5Se was there observed a positive effect on the damaged spermatozoa level in comparison with groups C, 1Se and 3Se at 4 °C. In conclusion, the applied concentrations of sodium selenite had a positive effect on the level of oxidative stress in all experimental groups, but mainly at concentration of 5 µg.ml–1 of sodium selenite, especially at 4 °C. However, the effect of selenium was not sufficient for improving the sperm viability.

Optical cryomicroscopy and differential scanning calorimetry of buffer solutions containing cryoprotectants

In the pharmaceutical industry, cryoprotectants are added to buffer formulations to protect the active pharmaceutical ingredient from freeze- and thaw damage. We investigated the freezing and thawing of aqueous sodium citrate buffer with various cryoprotectants, specifically amino acids (cysteine, histidine, arginine, proline and lysine), disaccharides (trehalose and sucrose), polyhydric alcohols (glycerol and mannitol) and surfactants (polysorbate 20 and polysorbate 80). Hereby, we employed optical cryomicroscopy in combination with differential scanning calorimetry in the temperature range to -80 °C. The effect of cryoprotectants on the morphology of the ice crystals, the glass transition temperature and the initial melting temperature is presented. Some of the cryoprotectants have a significant impact on ice crystal size. Disaccharides restrict ice crystal growth, whereas surfactants and glycerol allow ice crystals to increase in size. Cysteine and mannitol cause dehydration after thawing. Either one or two glass transition temperatures were detected, where arginine, surfactants, glycerol, proline and lysine suppress the second, implying a uniform freeze-concentrated solution. The initial melting temperature of pure buffer solution can be shifted up by adding mannitol, both disaccharides and both surfactants; but down by glycerol, proline and lysine.

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.

Addition of pomegranate juice (Punica granatum) in tris-based extender improves post-thaw quality, motion dynamics and in vivo fertility of Nili Ravi buffalo (Bubalus bubalis) bull spermatozoa

The aim of the present study was to determine the protective effects of pomegranate juice in tris-based extender on semen parameters, computer-assisted sperm analysis (CASA) motion characteristics and field fertility of post-thawed Nili Ravi buffalo (Bubalus bubalis) bull spermatozoa. Two consecutive ejaculates/collection from each of the five adult Nili Ravi buffalo bulls were collected with artificial vagina at 42°C for a period of 7 weeks, diluted in extender containing different concentrations of pomegranate juice (0.0%, 2.5%, 5%, 7.5% and 10%). Diluted samples were packed and frozen in 0.54 ml French straws. The addition of 10% pomegranate juice in extender significantly improved post-thaw sperm morphology (%), motilities (CASA total motility, progressive motility (%) as well as VAP, VSL, VCL, STR, DAP, DSL) compared to the control group (p < 0.05). Plasma membrane, acrosome membrane and DNA integrity were significantly higher in extender with 10% pomegranate juice than the control group (p < 0.05). Field fertility rate (60.39% vs. 46.53%) was higher (p < 0.05) in extender with 10% pomegranate juice as compared to the control. It is therefore concluded that the addition of 10% pomegranate juice in tris-based extender improves post-thaw semen parameters, CASA motion dynamics and field fertility in Nili Ravi buffaloes.

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.

Ostrich egg yolk improves post thaw quality and in vivo fertility of Nili Ravi buffalo (Bubalus bubalis) bull spermatozoa

Egg yolk containing a higher ratio of phospholipids and cholesterol may have better cryoprotective effect to buffalo spermatozoa during cryopreservation. Our objectives were to ascertain the comparison of Ostrich and chicken egg yolk in semen extender on post thaw quality, motion dynamics and in vivo fertility of Nili Ravi buffalo (Bubalus bubalis) bull spermatozoa. Semen samples (n = 45) from five bulls were collected once a week for a period of nine weeks and diluted in Triladyl^® extender having different concentrations of Ostrich egg yolk (10%, 15%, 20%) and 20% chicken egg yolk as control at 37 °C. Diluted semen samples were frozen in 0.54 mL French straws with programmable freezer. Post thaw sperm progressive motility (%), morphology (%), average path velocity (μm/s), straight line velocity (μm/s), Linearity (%), straightness (%), length of straight line path (μm), plasma membrane integrity (%), acrosome membrane integrity (%), DNA integrity (%) and mitochondrial activity were higher (P < 0.05) in spermatozoa cryopreserved in extender containing 20% Ostrich egg yolk as compared to 20% chicken egg yolk and other groups. The fertility rates (67.61% vs 54.2%) were higher (P < 0.05) in buffaloes inseminated with semen doses frozen in extender containing 20% Ostrich egg yolk than the 20% chicken egg yolk. It is concluded that 20% Ostrich egg yolk in extender improves post thaw semen quality, motion dynamics and in vivo fertility in Nili Ravi buffaloes.

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.

Freezability of water buffalo bull (Bubalus bubalis) spermatozoa is improved with the addition of curcumin (diferuoyl methane) in semen extender

Effects of curcumin as antioxidant in extender were evaluated on freezability of buffalo spermatozoa. Semen from each of the five bulls (n = 3 replicates, six ejaculates/bull, a total of 30 ejaculates) was diluted in Tris-citric acid extender containing curcumin (0.5, 1.0, 1.5 or 2.0 mM) or control. At pre-freezing and post-thawing, total antioxidant contents (μM/L) and lipid peroxidation levels (μM/ml) were higher (p < .05) and lower (p < .05) respectively, with 1.5 and 2.0 mM compared to 0.5 and 1.0 mM curcumin and control. At post-thawing, progressive motility (PM, %) and rapid velocity (RV, %) were higher (p < .05) with 1.5 mM compared to other doses of curcumin and control (except in case of RV, 1.5 was similar with 1.0 mM). Kinematics (average path velocity, μm/s; straight-line velocity, μm/s; curved-line velocity, μm/s; straightness, %; linearity, %), in vitro longevity (%, PM and RV) and DNA integrity (%) at post-thawing were higher (p < .05) with 1.5 mM compared to control. At post-thawing, supravital plasma membrane integrity (%) and viable spermatozoa with intact acrosome (%) were higher with 1.5 compared to 2.0 mM curcumin and control. We concluded that freezability of water buffalo spermatozoa is improved with the addition of 1.5 mM curcumin in extender.