Role of sperm motility and acrosome integrity in the filtration of bovine semen

Filtration techniques are advantageous over colloidal centrifugation in improving freezability of low-quality buffalo bull (Bubalus bubalis) ejaculates

The study compared efficacy of three sperm selection techniques in improving freezability of low-quality Murrah buffalo bull ejaculates. Sephadex (SEP), Sephadex ion-exchange filtration (SIE), and 40/80% BoviPure™ (BP) gradient centrifugation protocols were standardized (ejaculates, n = 24). In Experiment-I, Sephadex G-75, G-100, and combined Sephadex G (75-100) column filtrates were compared. In Experiment-II, BP protocols: 200 g-10 min, 250 g-5, and 10 min, 300 g-10, and 15 min were compared. In fresh semen, Sephadex G (75-100) filtration and 250 g-5 min BP protocol improved sperm functions and were used in Experiment-III, where SEP G (75-100), SIE G (75-100), and 250 g-5 min BP processed ejaculates (n = 48) were cryopreserved and compared at post-thaw stage. The mean recovery rate differed in order: SEP > SIE > BP. SIE filtration significantly improved progressive motility, livability, membrane integrity, bovine cervical mucus penetration and live non-apoptotic sperm. Compared with control, all three techniques equally reduced post-dilution and post-thaw lipid peroxidation (LPO) rate. SEP post-thaw filtrates observed lower cryocapacitation-like changes, LPO (C11-BODIPY581/591), and higher active mitochondria than other treatments. SIE and SEP equally improved post-thaw acrosome-intact sperm over BP. Filtration techniques, preferably, Sephadex ion-exchange filtration can most efficiently process low-quality buffalo bull ejaculates for cryopreservation and improve freezability.

Effect of diluent type, cryoprotectant concentration, storage method and freeze/thaw rates on the post-thaw quality and fertility of cryopreserved alpaca spermatozoa

This study compared protocols for cryopreservation of ejaculated, papain-treated alpaca spermatozoa. This included different concentrations of egg yolk (EY; 5, 10 or 15%) and glycerol (2, 5 or 10%), diluent types (SHOTOR, lactose, skim milk or INRA-96™), freeze rates (2, 4 or 8 cm above liquid nitrogen; LN), thaw rates (37 °C for 1 min or 42 °C for 20 sec) and storage vessels (pellets, 0.25 mL straws or 0.5 mL straws). Spermatozoa were assessed pre-freeze and 0, 30, 60 and 90 min post-thaw. Forty-one hembras were inseminated with either fresh, papain-treated or frozen-thawed spermatozoa. Motility was affected by EY concentration (P < 0.001), diluent type (P < 0.001), freeze rate (P = 0.003) and storage vessel (P = 0.001). Viability was affected by EY concentration (P < 0.001), diluent type (P < 0.001), storage vessel (P = 0.002) and thaw rate (P = 0.03). For artificial insemination (AI), semen was diluted 1:3 in a lactose-based diluent, with 5% EY and glycerol. Freezing was in 0.5 mL straws, 2 cm above LN for 4 min then thawing at 37 °C for 1 min. Pregnancy rates of those ovulated (n = 26) were not different (1/5 fresh, 1/4 papain-treated, 0/17 frozen-thawed; P = 0.10). Pregnancy can be achieved after AI with papain-treated spermatozoa. Further work is needed to determine the optimal dose, timing and location for insemination.

Sperm preparation through Sephadex™ filtration improves in vitro fertilization rate of buffalo oocytes

Routinely, swim-up method is used to separate high-quality sperm; however, long processing time and close cell-to-cell contact during the centrifugation step are inevitable elements of oxidative stress to sperm. The objective was to evaluate Sephadex^™ and glass wool filtration to separate motile, intact and viable sperm for in vitro fertilization in buffalo. The cumulus-oocyte complexes (COCs) were collected from ovaries of slaughtered buffaloes by aspiration and matured for 24 hr in CO₂ incubator at 38.5°C and 5% CO₂ . Matured COCs were rinsed twice in fertilization TALP and placed in the pre-warmed fertilization medium without sperm. Cryopreserved buffalo semen was thawed at 37°C for 30 s and processed through Sephadex^™ , glass wool filtration and swim-up (control). Total and motile sperm recovery rates were assessed, resuspended in fertilization TALP and incubated for 15-20 min in CO₂ incubator. Samples prepared by each method were divided into two aliquots: one aliquot was studied for sperm quality (progressive motility, membrane integrity, viability, liveability), while the other was subjected to co-incubation with sets of 10-15 in vitro matured oocytes. Data on sperm quality were analysed by ANOVA, while in vitro fertilizing rates were compared by chi-squared test using SPSS-20. Least significant difference (LSD) test was used to compare treatment means. Glass wool filtration yielded higher total and motile sperm recovery rate, while Sephadex^™ filtration improved (p < .05) sperm quality (progressive motility, membrane integrity, viability, liveability). Sperm preparation through Sephadex filtration yielded higher in vitro fertilization rate in terms of cleavage rate compared to glass wool filtration and swim-up (control). In conclusion, cryopreserved Nili-Ravi buffalo sperm selected through Sephadex filtration showed improved quality and yielded better fertilization rates (cleavage rate) of in vitro matured/fertilized oocytes. Sephadex filtration could be a promising technique for use in in vitro fertilization in buffalo.

A comparative study of Sephadex, glass wool and Percoll separation techniques on sperm quality and IVF results for cryopreserved bovine semen

The aim of this study was to compare the effects of spermatozoa separation techniques on sperm quality and in-vitro fertilization (IVF) results for cryopreserved bovine semen. Sephadex, glass wool and Percoll gradient separation techniques were used for sperm separation and sperm motility, morphology and membrane integrity were evaluated before and after separation. Also, cleavage and blastocyst developmental rate were investigated after IVF with sperm recovered by each separation technique. The motility of samples obtained by the three separation techniques were greater compared to the control samples (p < 0.05). The percentage of spermatozoa with intact plasma-membrane integrity, identified by 6-carboxyfluoresceindiacetate/propidium iodide fluorescent staining and the hypo-osmotic swelling test, was highest in the glass wool filtration samples (p < 0.05). The cleavage and blastocyst rate of total oocytes produced from glass wool filtration samples were also higher than the control and Sephadex filtration samples (p < 0.05), but were not significantly different from Percoll separation samples. However, a significantly greater number of cleaved embryos produced by glass wool filtration developed to blastocyst stage than those produced by Percoll separation (p < 0.05). These results indicate that spermatozoa with good quality can be achieved by these three separation techniques and can be used for bovine IVF. In particular, it suggests that glass wool filtration would be the most effective method of the three for improving sperm quality and embryo production for cryopreserved bovine spermatozoa.

Sephadex and sephadex ion-exchange filtration improves the quality and freezability of low-grade buffalo semen ejaculates

The effect of sephadex and sephadex ion-exchange filtration on the improvement in quality and freezability of low-grade buffalo semen ejaculates was assessed. Two types of filtration columns were used: one containing only sephadex G-10 (FS) and the other sephadex G-10 along with ion-exchangers (diethyl amino ethane-52 (DEAE-52) cellulose and carboxy methyl-52 (CM-52) cellulose; FS+IE). Unfiltered samples served as controls. Semen ejaculates extended in Tris-citric acid (1:4) (n=16; initial motility 40-50%) were filtered at the rate of 1.5 ml/min under negative pressure at room temperature (28-30 degrees C). The mean recovery rate (%) of motile spermatozoa in the FS (85.9+/-1.51) and FS+IE (77.10+/-2.28) filtrates did not differ significantly. Percentages of sperm motility, normal acrosomes, and intact plasma membranes were highest (P<0.05) in FS+IE, intermediate (P<0.05) in FS and lowest (P<0.05) in controls at the three stages of cryopreservation (postfiltration final dilution, after equilibration, and after freezing). Mean sperm abnormalities were lowest (P<0.05) in the filtrates of FS+IE, moderate (P<0.05) in FS and highest in controls at all stages of freezing. Compared to dilution and equilibration, freezing greatly reduced (P<0.05) the overall percent motility, normal acrosomes and intact plasma membranes. The spermatozoa eluted through FS+IE columns proved more resistant (P<0.05) in bearing dilution, equilibration, freezing and thawing stresses than the spermatozoa from FS and control samples. It is concluded that filtration systems containing an FS+IE column can effectively enhance the quality and freezability of extended, low quality buffalo semen.

Effect of column filtration upon the quality parameters of fresh dog semen

We filtered dog semen through various resin columns to obtain a quick, simple system for improving semen quality. Fresh ejaculates were filtered through columns with either glasswool or a chemically-inert polypropylene network disc. The columns were filled with Sephadex G-15 (nonionic resin), Sephadex A-50 (anionic-exchange resin), Sephadex C-50 (cationic-exchange resin) or a combination of Sephadex A-50 and C-50. Filtration through glasswool improved semen quality, with a significant (P < 0.001) increase in the percentage of viability and decrease in the percentage of altered acrosomes (P < 0.001) and total abnormalities (P < 0.001). Total motility was not modified, but curvilinear velocity or linearity of the movement were improved using the glasswool bed. The effect of the glasswool was so intense that it masked the effects of the filtration resins. Substitution of glasswool by polypropylene discs resulted in an unmasking of the effects of the resins, although the polypropylene exerted slight effects on semen. Elution of the spermatozoa through Sephadex G-15 or Sephadex C-50 resulted in a decrease of altered acrosomes. However, filtration through Sephadex A-50 increased viability and decreased the percentage of altered acrosomes and total abnormalities. Combined filtration through Sephadex A-50 and C-50 yielded the combined results observed with the resins individually. Ultrastructural imaging of the interaction between spermatozoa and the beds and resins showed that the cells were loosely deposited upon the glasswool fibers and the Sephadex G-15 particles, whereas close interaction was observed between spermatozoa and Sephadex A-50 and C-50 particles. The whole of the sperm cell bound to C-50 particles, whereas spermatozoa were specifically bonded to A-50 particles in the apical region of the head and in segments of the tail, which were periodically distributed. The data suggest that filtration through glasswool or an anionic resin-exchange can significantly improve dog semen quality.