Effects of Extender Type, Storage Time, and Temperature on Bull Semen Parameters

Bull Semen Obtained on Beef Farms by Electroejaculation: Sperm Quality in the First Two Hours of Storing with Different Extenders and Holding Temperatures

Sperm quality decreases over time, so bull semen may need to be preserved after field collection. However, the effect of handling such semen samples from commercial farms and placing them in very short-term storage has not been elucidated. Therefore, ejaculate from 25 bulls from 1 dairy and 14 beef cattle farms were collected under farm conditions and evaluated for semen quality during the first two hours after collection. Two commercial extenders (AndroMed^® and BIOXcell^®) and two different storage temperatures (5 °C and room temperature) were used to evaluate the influence on semen quality and sperm kinetics in ejaculates grouped into three evaluation times, based on time since collection (Time 1: <75 min, n = 7; Time 2: 75-105 min, n = 11; and Time 3: 105-120 min, n = 7). Classical semen parameters, sperm motion kinetics by CASA and colony-forming units were assessed. The differences between both extenders in curvilinear and straight-line velocities (VCL and VSL) for the different time groups (Time 2 and Time 3) were statistically significant for p < 0.05. AndroMed^® showed lower VSL, straightness and linearity in sperm compared to BIOXcell^® (p < 0.05). In conclusion, AndroMed^® induced more curvilinear movement, while BIOXcell^® stimulated straighter motility.

Defects in sperm capacitation/fertilizing ability are equally prevalent across ages in men seeking fertility assistance

RESEARCH QUESTION

How do capacitation ability, measured by Cap-Score™, and traditional semen analysis measures (volume, concentration, motility) change with age in men questioning their fertility (MQF)?

DESIGN

Cap-Score and semen analysis measures were obtained from MQF (n = 2652; multicentric design: 35 reproductive endocrinologist prescribers, n = 16 clinics). Morphology was not included due to differences among clinics. A Mann-Whitney test was used to compare Cap-Scores between MQF and men with known recent paternity (n = 76). The following age groups were constructed for MQF: 20-24, 25-29, 30-34, 35-39, 40-44, 45-49 and 50+. Associations between semen analysis, Cap-Score and age groups were evaluated using mixed-model analysis of variance to identify possible influence of Cap-Score collection kit type (n = 763 collected at home; n = 1889 collected at clinics).

RESULTS

MQF had reduced capacitation ability (mean ± SE; 29.25 ± 0.15 versus 35.34 ± 0.88; P < 0.001). No change in Cap-Score (P = 0.916) or concentration (P = 0.926) was detected with age group. In contrast, both volume (P = 0.008) and % motility (P < 0.001) declined with age.

CONCLUSIONS

Men presenting because of difficulties in generating pregnancy showed equivalent reductions in capacitation ability regardless of age. In contrast, motility and volume declined with age. These data suggest that capacitation ability is a more sensitive indicator of male fertility across age groups than traditional semen analysis and should not be reserved for older men. Importantly, these data do not address whether sperm fertilizing ability declines in the general population as men age. Instead, they indicate that if men are having difficulty conceiving, no matter what their age, then defects in sperm fertilizing ability are equally likely to be the cause.

The Effect of Different Extenders on the Quality Characteristics of European Red Deer Epididymal Sperm Stored at 5 °C

The aim of this study was to evaluate the effect of different extenders on the quality of European red deer epididymal sperm stored at 5 °C. Epididymal spermatozoa were collected post mortem from 10 stags and diluted with three extenders (Bovidyl®, BoviFree®, and BioXcell®) and stored at 5 °C. Sperm motility (TMOT), motility parameters (system CASA), plasma membrane integrity (SYBR-14+/PI−), acrosomal membrane integrity (FITC-PNA−/PI−), mitochondrial activity (JC-1/PI), viability, and apoptotic-like changes (YOPRO/PI) were evaluated. The analyses were conducted on the first and successive days of storage (D1−D7). The applied extender, storage time, and the interactions between these factors significantly (p < 0.001) affected most of the analyzed parameters whose values were highest in sperm samples stored in Bovidyl®, regardless of storage time. In Bovidyl®, BoviFree®, and BioXcell® extenders, TMOT values were estimated at 83%, 63%, and 59%, respectively, on D3. The extenders significantly influenced DNA integrity on D7. The percentage of dead sperm increased from D3. The quality of stored sperm cells was significantly influenced by the extenders’ biochemical composition. BoviFree® and BioXcell® contain glycerol which could contribute to deteriorating the quality of spermatozoa stored at 5 °C. Sperm cells stored in the egg yolk-based extender (Bovidyl®) were characterized by the highest viability and functionality.

Comparative ejaculatory response, fresh and frozen semen quality and fertility to artificial vagina vs electroejaculation method of semen collection in mithun (Bos frontalis) bulls

The study aimed to describe a comparative ejaculatory response, fresh and frozen-thawed semen quality and fertility of semen collected by artificial vagina and electroejaculation in mithun. Experimental bulls were divided into two groups, G-I: young bulls (n = 4; 4-5 years of age) and G-II: older bulls (n = 4; 8-10 years of age). Sixteen ejaculates were collected from each group G-I (AV₁ ) and G-II (AV₂ ) by artificial vagina method (control). Thirty-six ejaculates were collected from the same bulls from each group G-I (EE₁ ) and G-II (EE₂ ) by electroejaculation method (treatment). The study did not reveal any significant (p > 0.05) difference in the ejaculatory responses between EE₁ and EE₂ . Mann-Whitney U test indicated that salivation discomfort sign score was significantly (p < 0.05) higher in EE₁ . Fresh and frozen-thawed semen quality parameters, and motility and velocity profiles recorded by computer-assisted sperm analyser were significantly (p < 0.05) lower in electroejaculation than the artificial vagina. The conception rates (AV₁ vs EE₁ & AV₂ vs EE₂ ) at day 35-45 post insemination were nonsignificantly higher (p > 0.05) in the artificial vagina group. It concluded that, although artificial vagina method has better semen quality, nevertheless, electroejaculation has the potential for semen collection from free-range mithun bulls to incorporate in assisted reproductive technology procedures.

The addition of crocin in the freezing medium extender improves post-thaw semen quality

Semen cryopreservation is arguably the most important method or technique contributing to the advancement of modern animal production. However, the quality of sperm after thawing is still highly variable. The addition of antioxidant compounds to the freezing medium has been used customarily to counteract the harmful effects of Reactive Oxygen Species (ROS) that are produced during the freeze/thaw process. Crocin, a potent antioxidant, improves the fertilizing capacity of spermatozoa. In this study, we evaluated the potential of crocin (0, 0.5 and 1 mM) as an extender additive to diminish the damaging effects of cryopreservation on bovine spermatozoa. Post-thaw semen quality was assessed by means of motility, viability and lipid peroxidation (LPO). We further investigated the effect of crocin supplementation upon freezing on sperm quality parameters during their incubation at 37°C for up to 2 hr. Overall, the data assessment indicates that crocin facilitated a general improvement of the quality of freeze/thawed spermatozoa, under the present experimental conditions. Crocin (1 mM) maintained a higher percentage of alive spermatozoa with intact acrosome with rapid and progressive motility, compared to the control extender. Moreover, the spermatozoa cryopreserved in the presence of crocin exhibited higher values in CASA kinematic parameters (VCL, VSL, VAP, ALH) immediately after thawing. Furthermore, the positive effect of crocin on motility parameters was also sustained over a period of 2 hr incubation at 37°C. This effect of crocin may be attributed to the observed inhibition of LPO during the incubation period. Thus, the results indicate that the addition of crocin (especially at a final concentration of 1 mM) in the freezing extender medium may benefit the preservation of the quality parameters of spermatozoa that are compromised by the freeze/thaw heat shock and the stress during handling for IVF or artificial insemination.

Effect of Extender, Storage Time and Temperature on Kinetic Parameters (CASA) on Bull Semen Samples

Simple Summary

The bull accounts for a great part of the economic value of beef herds managed with natural mating, with the Bull Breeding Soundness Evaluation (BBSE) performed in the field becoming essential. Part of the BBSE is the semen-quality evaluation (classical and kinetic parameters) that can be performed in situ (by trained practitioners) or at laboratories, with semen being short-term stored and shipped. The extender used as well as the storage temperature and duration may affect its quality. Thus, our aim was to explore the best conditions to preserve CASA kinetic parameters, to be reliably assessed afterwards. CASA parameters were preserved for up to 4–6 h post-ejaculation, except for AndroMed^® in most of the parameters. Motility decreased from 4–6 h up to 24 h, with the best values obtained with BIOXcell^® at 5 °C. The rest of kinetic parameters worsened when analyses were performed at 24 h. Therefore, we suggest evaluating seminal quality as soon as possible. However, using BIOXcell^®, either at 5 °C or room temperature, and INRA96^® at room temperature, sperm motility can be reliably evaluated for up to 6 h. These results help to fix adequate protocols for the short-term storage and shipment of bovine semen collected under field conditions.

Abstract

CASA kinetic parameters are often evaluated in a diagnostic centre. How storage conditions affect ejaculates up to evaluation is unclear. We assessed, in 25 commercial bulls electroejaculated in the field, the impact of time until evaluation (0–2 h, 4–6 h, and 24 h post-ejaculation), holding temperature (5 °C vs. room temperature), and extender (AndroMed^®, BIOXcell^® or INRA96^®) on CASA kinetic parameters. Total and progressive motility, VCL, VAP, VCL, ALH, BCF, STR, LIN, and WOB were assessed. CASA kinetic parameters were preserved for up to 4–6 h post-ejaculation, except for AndroMed^®. Regardless of extender or temperature, motility decreased from 4–6 h up to 24 h, with the best values obtained with BIOXcell^® at 5 °C. Our results suggest that BIOXcell^® can preserve sperm motility for up to 6 h, either at 5 °C or room temperature, and also INRA96^® at room temperature, with motility assessments and the percentage of the most rapid sperms being the lowest with INRA96^® at 5 °C. The kinetic parameters decreased when analyses were performed at 24 h. Therefore, we suggest evaluating seminal quality as soon as possible, before 6 h after collection. These results help to fix adequate protocols for the short-term storage and shipment of bovine semen collected under field conditions.