Correlation between dissolved oxygen level, antioxidants and oxidants in semen diluted with partially deoxygenated extender at various stages of cryopreservation

BACKGROUND

Dissolved oxygen (DO) in semen dilutor may lead to the production of reactive oxygen species (ROS) and buffalo sperm may become more prone to deleterious effects of ROS due to the presence of high amounts of polyunsaturated fatty acids (PUFAs) in their membranes.

OBJECTIVE

To study the correlation between dissolved oxygen level, antioxidants and oxidants in semen diluted with partially deoxygenated extender at various stages of cryopreservation.

MATERIALS AND METHODS

Each semen sample was split into two aliquots viz., Aliquot I [diluted with Extender I (control: without deoxygenation)] and Aliquot II [diluted with Extender II: partially deoxygenated by liquid nitrogen (LN) flushing], which were diluted, filled in straws, cryopreserved and evaluated post-thaw.

RESULTS

The DO levels (P < 0.05) decreased significantly after LN flushing of the extender and they increased significantly (P < 0.05) in post-thaw semen. The progressive motility, viability, hypo-osmotic swelling response, acrosomal integrity, glutathione peroxidase (GPx), total antioxidant capacity (TAC) and superoxide dismutase (SOD) decreased significantly (P < 0.05) in both control and treated semen after thawing. SOD and TAC were positively correlated in semen treated with normal extender at the pre-freeze stage; however, in semen treated with partially deoxygenated extender, no correlation was found between SOD and TAC at the pre-freeze stage. ROS and total TAC were negatively correlated in semen treated with partially deoxygenated extender at the pre-freeze stage; however, no correlation was found between ROS and TAC in control semen.

CONCLUSION

The partial deoxygenation of extender affects the correlation between sperm quality parameters, antioxidants, and oxidants during different stages of semen cryopreservation. doi.org/10.54680/fr22310110712.

Seasonal variation in heat shock proteins (hsp70 and hsp90) and their association with frozen semen quality and fertility in buffaloes

BACKGROUND

Heat shock protein is considered as a potential indicator of animal adaptation to harsh environmental stresses and its expression has been correlated with resistance to stress.

OBJECTIVE

To evaluate the seasonal variation in heat shock proteins (hsp70 and hsp90) and their association with frozen semen quality and fertility in buffaloes.

MATERIALS AND METHODS

During summer and winter, ejaculates (n = 32) were collected from buffalo bulls, diluted with freshly prepared Andromed extender (maintained at 34 degree C) up to 80 million sperm per mL. The diluted semen was filled in French midi straws, equilibrated, and cryopreserved. The semen was evaluated at pre-freeze and post-thaw stages for heat shock proteins (HSP70 and HSP90), and sperm quality parameters.

RESULTS

The levels of HSP70 were significantly (P = 0.00) higher in summer season compared to winter season. The HSP70 had a positive correlation with mass motility (P <0.05; r = 0.39), live sperm count (P < 0.05; r = 0.47), and acrosomal integrity (P < 0.05; r = 0.37). The first artificial insemination conception rate (FAICR) had a positive correlation with HSP70 (P < 0.05; r = 0.47), and HSP90 (P < 0.05; r = 0.59), in frozen-thawed semen.

CONCLUSION

The assessment of the levels of heat shock proteins may help in predicting cryo-tolerance and fertility of buffalo semen during various seasons.

A new modified Kies Fréchet distribution: Applications of mortality rate of Covid-19

The purpose of this paper is to identify an effective statistical distribution for examining COVID-19 mortality rates in Canada and Netherlands in order to model the distribution of COVID-19. The modified Kies Frechet (MKIF) model is an advanced three parameter lifetime distribution that was developed by incorporating the Frechet and modified Kies families. In particular with respect to current distributions, the latest one has very versatile probability functions: increasing, decreasing, and inverted U shapes are observed for the hazard rate functions, indicating that the capability of adaptability of the model. A straight forward linear representation of PDF, moment generating functions, Probability weighted moments and hazard rate functions are among the enticing features of this novel distribution. We used three different estimation methodologies to estimate the pertinent parameters of MKIF model like least squares estimators (LSEs), maximum likelihood estimators (MLEs) and weighted least squares estimators (WLSEs). The efficiency of these estimators is assessed using a thorough Monte Carlo simulation analysis. We evaluated the newest model for a variety of data sets to examine how effectively it handled data modeling. The real implementation demonstrates that the proposed model outperforms competing models and can be selected as a superior model for developing a statistical model for COVID-19 data and other similar data sets.

Study on correlation of sperm quality parameters with antioxidant and oxidant status of buffalo bull semen during various stages of cryopreservation

This investigation was carried out to study the correlation of sperm quality parameters with antioxidant and oxidant status of buffalo bull semen during various stages of cryopreservation. Semen samples were evaluated for sperm parameters (mass motility [MM], concentration [CON], progressive motility [PM], viability [VIB], acrosomal integrity [AI] and hypo-osmotic swelling [HOS] response), antioxidants (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx] and total antioxidant capacity [TAC]) and oxidants (Lipid peroxidation [LPO] and reactive oxygen species [ROS]) at fresh, pre-freeze and post-thaw stages. Sperm parameters (PM, VIB, AI and HOS response) and antioxidants (SOD, CAT and TAC) were significantly (p < .05) reduced at fresh stage, and oxidants (LPO and ROS) were significantly (p < .05) increased at pre-freeze and post-thaw stages. At fresh stage, MM was negatively correlated with LPO (p < .05), and CON was positively correlated with SOD, TAC and CAT, negatively correlated with LPO and CAT was positively (p < .01) correlated with VIB and HOS response. At pre-freeze stage, CAT was positively correlated with PM and AI (p < .05), and AI was negatively (p < .05) correlated with ROS. At post-thaw stage, CAT was positively correlated with PM, VIB, HOS response and AI,, and LPO was negatively correlated with HOS, AI and VIB. The study of correlations of these parameters at different preservation stages with bull fertility may play an important role in developing models for predicting future fertility of bulls in the absence of conception rate data.

Effect of Liquid Nitrogen Flushing of Extender on Seminal Antioxidant Profile of Murrah Buffalo during Cryopreservation

BACKGROUND

The dissolved oxygen in the extender may act as a source for the production of reactive oxygen species that may lead to reduced seminal antioxidant profile which in turn may be responsible for impaired frozen thawed sperm quality and fertility.

OBJECTIVE

To study the effect of adding liquid nitrogen into the extender on semen freezability and seminal antioxidant profile in buffalo.

MATERIALS AND METHODS

Semen extender was prepared freshly and divided into two sub extenders namely, Extender I: control (non deoxygenated) and Extender II: partially deoxygenated by using LN₂ flushing). The estimation of dissolved oxygen (DO) level was done in both extenders. Semen samples with mass motility of ≥ 3+ and individual progressive motility of 70% and above, collected from murrah buffalo bulls were utilized for the present study. Each semen sample was split into two group's viz., group I: diluted with extender I and group II: diluted with extender II up to 60×10⁶ sperm/mL. The diluted semen samples were packed into French mini straws (0.25 mL), sealed with polyvinyl alcohol powder, kept for 3 h at 5°C for equilibration and then kept in automatic programmable freezer until temperature of straws reached -145°C followed by plunging into liquid nitrogen (-196°C). The evaluation of semen samples was carried out for various seminal attributes (sperm motility, live sperm count, acrosomal integrity, and hypo-osmotic swelling (HOS) response) and antioxidant profile (superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (TAC)) at pre freeze and post thaw stage.

RESULTS

Sperm motility, live sperm count, acrosomal integrity, HOS response were significantly (P<0.05) higher in group II as compared to group I. The average seminal SOD, GPx and TAC levels were significantly (P<0.05) higher in group II as compared to group I at pre freeze and post thaw stage.

CONCLUSION

It is concluded that partial deoxygenation of the extender prior to its addition to semen enhances sperm quality in terms of sperm motility, live sperm count, acrosomal integrity, and hypo-osmotic swelling (HOS) response and also improves seminal antioxidant profile (superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant capacity (TAC).

Effect of Cholesterol-loaded Cyclodextrin on Membrane and Acrosome Status of Hariana Bull Sperm during Cryopreservation

BACKGROUND

The membrane and acrosomal integrity of sperm play a vital role in fertilization process; however they are compromised upon cryopreservation.

OBJECTIVE

To study the effect of cholesterol-loaded cyclodextrin (CLC) on membrane and acrosome status of Hariana bull sperm during cryopreservation.

MATERIALS AND METHODS

Semen samples collected from Hariana bulls with mass motility ≥ 3+ and individual progressive motility ≥ 70% were utilized in the study. Each ejaculate was split into two parts, one part being evaluated freshly for various seminal attributes and the other part being diluted in Tris diluent (without egg yolk and glycerol) to obtain a final concentration of 120×10⁶ sperm/mL. The diluted semen was divided into four treatments: Group I, without CLC (control); Group II, with CLC at 0.5 mg per 120 million sperm; Group III, at 1.0 mg per 120 million sperm; Group IV, at 2.0 mg per 120 million sperm. All aliquots were incubated for 15 min at 37°C and each sample was diluted with Egg yolk-Tris-Glycerol (EYTG) extender up to 80×10⁶ sperm/mL. The diluted semen samples were packed in French mini straws (0.25 mL), sealed and equilibrated at 4°C for 4 h followed by cryopreservation. The samples at pre-freeze and post-thaw stage were evaluated for membrane and acrosomal integrity, as well as primary, secondary and tertiary acrosomal damages.

RESULTS

The membrane and acrosomal integrity was significantly higher in group II as compared to groups I, III, and IV, at pre-freeze and post-thaw stage (P<0.05). The primary and secondary acrosomal damage were significantly reduced in group II compared to other groups (P<0.05). No significant difference in tertiary acrosomal damage was found among different groups.

CONCLUSION

CLC improves the membrane and acrosomal integrity, and reduces primary and secondary acrosomal damages during cryopreservation of Hariana bull sperm.

Effect of Dilution on Cryosurvival of Low Sperm Doses: A Review

　　BACKGROUND: Sperm concentration needed for artificial insemination (AI) to obtain reasonable fertility, taking into consideration genetic value of bull and numerous others components is one of the essential constituents for successful breeding program. AI-doses containing low sperm numbers are increasingly widespread to optimize the benefit of elite bulls, as well as to accommodate an eventual wider application of sex-sorted semen. Viability is reduced when higher dilutions of semen are carried out for production of low sperm doses. The reduction in viability may be due to dilution effect as well as due to dilution of numerous essential constituents in seminal plasma at higher dilutions. Fertility level of bull may play a pivotal role in determining the cryosurvival of low sperm doses and viability of low sperm doses may vary among bulls. This paper attempts to highlight studies dealing with the effect of dilution on cryosurvival of low sperm doses.

Effect of egg yolk powder on freezability of Murrah buffalo (Bubalus bubalis) semen

Aim:

The aim of this study was to investigate the effect of commercial egg yolk powder as an alternative to fresh egg yolk on freezability of Murrah buffalo semen.

Materials and Methods:

Semen samples (12) from 3 Murrah buffaloes (4 from each bull) with mass motility (≥3+) and total motility (70% and above) were utilized in this study. Immediately after collection, each sample was divided into four groups. Groups I was diluted up to 60×10⁶ sperm/ml with tris extender containing 10% fresh egg yolk and Groups II, III, and IV were diluted up to 60×10⁶ sperm/ml with tris extender containing 2%, 4%, and 6% egg yolk powder, respectively. Semen samples were processed and cryopreserved followed by examination of frozen semen samples after 24 h. Semen samples from each group were evaluated for total motility, viability, acrosomal integrity, abnormality, and hypo-osmotic swelling test (HOST) response after dilution, pre-freeze, and post-thaw stage.

Results:

Pre-freeze total motility was significantly (p<0.05) higher in Groups III and IV as compared to Groups I and II, and post-thaw total motility was significantly (p<0.01) higher in Group III as compared to other three groups. Viability was significantly (p<0.05) higher in Groups II, III, and IV than Group I at the pre-freeze stage. Significantly (p<0.01) higher viability and acrosomal integrity were recorded in Group III as compared to other three groups at the post-thaw stage. Abnormality was significantly (p<0.05) higher in Group IV than other three groups. HOST response was significantly (p<0.05) higher in Groups II and III than Groups I and IV at the pre-freeze and post-thaw stages.

Conclusion:

Addition of egg yolk powder at 4% level yielded significantly better results in terms of post-thaw semen quality as compared to the fresh egg yolk and other concentrations of egg yolk powder (2% and 6%).

Effect of incubation on freezability of cholesterol-loaded cyclodextrin treated buffalo (Bubalus bubalis) spermatozoa

Aim:

The aim of this study was to investigate the effect of incubation on freezability of cholesterol loaded cyclodextrin (CLC) treated buffalo spermatozoa.

Materials and Methods:

Semen samples with mass motility of 3+ and greater, collected from Murrah buffalo bulls were utilized. Immediately after collection, four equal groups of semen sample were made. Group I was kept as control and diluted with Tris upto concentration of 60×10⁶ sperm/ml, where as Groups II, III, and IV were treated with CLC at 3 mg/120× 10⁶ spermatozoa, incubated at 37°C for action of CLC for 10, 15 and 20 min, respectively, and diluted with tris upto concentration of 60×10⁶ sperm/ml. All groups were subjected to equilibration and freezing. The evaluation of semen samples from all groups was carried out at fresh, pre-freeze and post-thaw stage for progressive motility, viability and hypo-osmotic swelling response (HOS response).

Results:

At the pre-freeze stage, significantly (p<0.05) higher percentage of progressive motility and viability was observed in treatment groups as compared to control with no significant difference among treatment groups. HOS response was significantly (p<0.05) higher in treatment groups as compared to control at pre-freeze stage. At post-thaw stage, significantly (p<0.05) higher percentage of progressive motility, viability and HOS response was recorded in Group II as compared to control and other treatment groups (III and IV). Group II retained significant post-thaw motility and viability at various post-thaw incubation periods.

Conclusion:

Incubation period of 10 min for CLC treated buffalo spermatozoa yielded significantly higher results in terms of freezability as compared to incubation for 15 and 20 min.