Appraisal and standardization of curvilinear velocity (VCL) cut-off values for CASA analysis of Japanese quail (Coturnix japonica ) sperm

Sodium dodecyl sulphate, N-octyl β-D glucopyranoside and 4-methoxy phenyl β-D glucopyranoside effect on post-thaw sperm motion and viability traits of Murrah buffalo (Bubalus bubalis) bulls

Sodium Dodecyl Sulphate (SDS), N-Octyl β-D Glucopyranoside (NOG), 4-Methoxy Phenyl β-D Glucopyranoside (4-MPG) as ice recrystallization inhibitors were added to Tris Egg Yolk Glycerol (TEYG) semen extender for cryopreservation of semen of buffalo bulls. Post-thaw sperm motion and viability traits were evaluated. Pilot study involved six semen ejaculates (2 ejaculates/bull, from three bulls); second experiment was conducted using twenty seven semen ejaculates (9 ejaculates/bull, from 3 bulls) and in third experiment three semen ejaculates (one bull) were used. Eight concentrations of SDS (2, 1, 0.5, 0.25, 0.15, 0.125, 0.0625 and 0.0312%), twelve concentrations of NOG (33, 22, 11, 5.5, 2.5, 0.75, 0.5, 0.25, 0.125, 0.0625, 0.03125 and 0.0156 mM), and, eleven concentrations of 4-MPG (220, 165, 110, 55, 50, 25, 12.5, 6.25, 3.125, 1.56 and 0.78 mM) were supplemented in TEYG semen extender to evaluate the post-thaw sperm motility and viability traits. Computer Assisted Sperm Analysis (CASA) was used to measure the kinetic and functional parameters for sperm motion traits, Hypo Osmotic Swelling Test (HOST) for sperm plasma membrane integrity, Eosin Nigrosin staining for viability and Rose Bengal staining for sperm abnormalities for all the experiments except for pilot study where only Total Motility (TM) and Rapid Progressive Motility (RP) were evaluated. Three freezing protocols; i) Normal P24 (freezing rate of -30 °C min^-1 from 4 °C to -15 °C; -40 °C min^-1 from -15 °C to -60 °C; and -50 °C min^-1 from -60 °C to -140 °C; and then plunged in liquid Nitrogen at -196 °C); ii) Moderate P25 (freezing rate of -30 °C min^-1 from 4 °C to -15 °C; -50 °C min^-1 from -15 °C to -60 °C; and -50 °C min^-1 from -60 °C to -140 °C; and then plunged in liquid Nitrogen at -196 °C); and iii) Rapid P26 (freezing rate of -30 °C min^-1 from 4 °C to -15 °C; -60 °C min^-1 from -15 °C to -60 °C; and -50 °C min^-1 from -60 °C to -140 °C; and then plunged in liquid Nitrogen at -196 °C) were evaluated using SDS 0.125% in TEYG semen extender. SDS ≤0.125%, NOG ≤0.0625 mM and 4-MPG ≤ 3.125 mM in TEYG buffalo semen extender improved significantly (p < .05) the kinetic and functional parameters as compared to the other Ice Recrystallization Inhibitors (IRIs) concentrations used for cryopreservation of buffalo bull semen in the pilot study. SDS 0.125% supplementation was the best IRI among all which resulted in improved kinetic and functional parameters of bull semen in second experiment. Conclusion was drawn that buffalo bull semen cryopreservation using sodium dodecyl sulphate, 0.125% as IRI in TEYG semen extender along with freezing protocol P 25 revealed optimum kinetic and functional parameters for post-thaw spermatozoa.

Cementing the relationship between conventional and advanced semen parameters

Background

Affordable conventional semen analysis remains a fundamental procedure to be performed routinely during the diagnosis of male infertility. Advanced semen analyses provide valuable clinical insights in treatment-related decision-making, but these are highly expensive and lack universal standardization. This study aimed at determining the relationship between conventional semen parameters, measured with assistance of computer-aided sperm analysis (CASA), and a set of advanced semen tests. Basic semen analysis (n = 124) was performed according to the World Health Organization (WHO) guidelines. Sperm DNA fragmentation and intracellular superoxide (O2−•) levels were assessed by flow cytometry. Seminal plasma thiobarbituric acid reactive substances (TBARS) levels as well as superoxide dismutase (SOD) and catalase (CAT) activity were measured by spectrophotometry. Spearman’s rank correlation coefficient was used, with significance set at p < 0.05.

Results

Semen pH correlated negatively with TBARS (p < 0.01). The proportions of total and progressively motile as well as rapid spermatozoa correlated positively with CAT activity (p < 0.05). Sperm viability correlated negatively with both O2−• (p < 0.05) and DNA fragmentation (p = 0.01), while normal morphology correlated negatively with O2−• levels (p < 0.05) and positively with CAT activity (p < 0.05). Straight-line velocity (VCL) and average-path velocity (VAP) correlated negatively with both O2−• (p < 0.01) and TBARS (p < 0.01). Amplitude of lateral head displacement (ALH) correlated negatively with O2−• (p < 0.01) and DNA fragmentation (p < 0.01), while its correlation with SOD activity was positive (p < 0.05).

Conclusion

The results obtained from this study support the validity of some CASA parameters as sensitive indicators of changes in sperm oxidative status and DNA integrity. Predicting advanced from conventional parameters through the building of linear regression models should be considered for future studies.

Mobility of Japanese quail spermatozoa and its relationship to egg fertility

Sperm mobility (SM) appears to be primary determinant of fertility in chicken and turkey. The aims of this study were to extend the concept to the Japanese quail by developing an assay to quantify SM, explaining the basis of SM using motility properties measured by CASA, and exploring the relationship between SM and egg fertility. The study was carried out in three stages: i) males (n = 20) and females (n = 20) were mated individually; ii) ejaculates were collected from 20 males, and SM was measured; iii) males (n = 20) and females (n = 20) were mated individually. In Stages I and III, data were collected for egg fertility, Sperm_OPVL and Holes_IPVL . In Stage II, SM assay was developed and assay conditions were defined: effect of sperm numbers on absorbance in Accudenz solution; effect of Accudenz concentration on sperm motility and mobility; effect of quail proctodeal gland foam extract and incubation temperature on SM at 37 and 41°C. The recorded absorbance of sperm movement was dependent on sperm numbers in the sperm suspension overlaying the Accudenz (p < .001). At 41°C, SM, progressively motile sperm, VCL, VSL and VAP were negatively affected by Accudenz concentration (p < .05). The effect of foam on SM and motility depended on an interaction between the concentration of foam extract and incubating temperature. Males were categorized into low, average and high SM phenotypes. These categories differed significantly (p < .001), but sperm motility and SM were not related to egg fertility. In conclusion, SM assay can be used to identify mobility phenotypes, but the poor relationship between SM and egg fertility indicates a need for further studies on interaction between the concentration of foam extract, incubating temperature, and in vivo sperm movement and egg fertilization success.

Ostrich ejaculate characteristics and male libido around equinox and solstice dates

The study evaluated the effect of time of the year in which changes in photoperiod occurs on ostrich semen characteristics and male libido. Semen was collected for 5 days before, on and 5 days after winter solstice (21 June 2016), spring equinox (22 September 2016), summer solstice (21 December 2016) and autumn equinox (20 March 2017) in the southern hemisphere. Semen was collected from 10 South African Black ostrich males (average age ± standard deviation; 4.5 ± 2.27 years) using the dummy female. Semen volume, sperm concentration, total sperm per ejaculate, sperm motility traits, percentage of normal sperm, head and tail abnormalities and percentage of affected sperm in the hypo-osmotic swelling test (HOS) were evaluated. Male libido defined as the willingness of males to mount the dummy female was also recorded. Semen samples collected around summer solstice, spring and autumn equinox were higher in sperm concentration and sperm output compared with winter solstice (P < 0.05). Study periods did not influence semen volume, sperm motility traits, the percentage of normal sperm, head abnormalities and HOS. Tail abnormalities were higher around winter solstice than around spring equinox (P < 0.05). Male libido and the success of semen collection were significantly higher around spring equinox (P < 0.05). Changes in photoperiod in the southern hemisphere do not affect semen production in ostriches. However, high sperm output and male libido around spring equinox and summer solstice dates suggest that these periods may be preferred for semen collection for artificial insemination and storage purposes.

Age-related declines in ejaculate quality and sperm kinematics vary among strains of Japanese Quail (Coturnix japonica)

For successful breeding programs, it is important to quantify the useful period of a male's reproductive life and it is often done simply by measurement of semen quality. This information is lacking for Japanese quail so we tested whether there is a decline in ejaculate quality and sperm kinematics with age, and whether the decline varies among strains. Nine males (n = 9) from each of 5 strains (A, B, C, D and E) were subjected to 4 semen collections (n = 16 per male) at 8, 16, 26 and 36 weeks of age. Ejaculate volume, sperm concentration and total sperm per ejaculate were measured, and sperm kinematics were analysed using a Sperm Class Analyser (SCA^® ). There was a significant effect of age for ejaculate volume, total sperm per ejaculate and per cent medium sperm. The effect of the interaction between age and strain was significant for percent progressive motile sperm, percent rapid sperm, velocity curvilinear, velocity straight line, velocity average path, linearity, straightness and beat cross frequency. Ejaculate volume peaked at Week 26 in all strains, while peak values for sperm concentration and total sperm per ejaculate were observed at Week 16 for most strains. There were declines in percent motile sperm, progressive motile sperm and rapid sperm, and in velocity curvilinear velocity, velocity straight line and velocity average path, by Week 16 for most strains. Linearity declined by Week 26 in some strains, and all strains showed a significant decline in beat cross frequency by that age. In conclusion, the ability of CASA to detect age-related changes in sperm kinematics makes it a valuable tool for identifying the best males and thus improving quail flock fertility. It is essential that breeders understand that age affects both sperm production and sperm kinematics, and that the changes vary with strain.