Preservation of rooster post-thawed sperm epigenetic modifications, fertility potential and other quality parameters in different extenders using reduced glutathione

Comparative assessment of thawing methods for frozen rooster sperm

Introduction

Cryopreservation, widely used in commercial poultry breeding, often reduces sperm motility, viability, and DNA integrity due to cryopreservation-induced damage. This study evaluates the effects of water bath and dry thawing systems on the post-thaw quality of rooster spermatozoa, addressing these challenges and exploring methods to enhance sperm quality.

Methods

The study compared the performance of water bath and dry thawing systems, both operated at 37°C for 30 s. Post-thaw assessments included sperm motility, morphology, kinematic characteristics, and DNA integrity. Key parameters such as total motility, progressive motility, curvilinear velocity (VCL), average path velocity (VAP), straight-line velocity (VSL), viability, morphological abnormalities, and DNA damage metrics were analyzed.

Results

The dry thawing system significantly improved sperm quality compared to the water bath method. Total motility and progressive motility were higher in the dry thawing system (82.38 and 33.18%, respectively) compared to the water bath method (68.14 and 21.20%). Kinematic parameters, including VCL (79.41 vs. 66.49 μm/s), VAP (47.52 vs. 37.42 μm/s), and VSL (27.18 vs. 21.59 μm/s), were superior in the dry thawing system. Viability improved (82.2 vs. 73.7%), while morphological abnormalities were reduced (23.9 vs. 35.8%). DNA integrity metrics, such as Tail DNA (%; 77.37 vs. 81.11%) and Olive Tail Moment (15.28 vs. 16.93), also showed reduced damage.

Discussion

The dry thawing system offers significant operational advantages, including portability, contamination-free operation, and consistent temperature maintenance, making it ideal for on-site applications. These features, combined with its ability to enhance sperm quality, highlight the dry thawing system as an effective alternative for poultry breeding. Its adoption could improve artificial insemination outcomes and address challenges associated with cryopreservation-induced damage during thawing.

Which is more effective in thawing frozen rooster sperm: varying temperature or duration?

Introduction

Cryopreservation of poultry sperm is crucial for preserving genetic diversity and protecting endangered breeds. Rooster sperm is highly sensitive to cryopreservation due to its high polyunsaturated fatty acid content, making it prone to damage during freezing and thawing. This study evaluated the effects of thawing temperatures and storage conditions on sperm quality, including motility, morphology, and viability.

Methods

Frozen rooster semen samples were thawed at 37°C for 30 seconds, 60°C for 5 seconds, or 72°C for 5 seconds and stored at 4°C for up to 48 hours. Sperm quality parameters, including motility, kinematic characteristics, abnormal morphology, and viability, were assessed at 0, 3, 6, 9, 12, 24, and 48 hours using a Computer-Assisted Semen Analyzer (CASA).

Results

Post-thaw motility varied significantly between thawing temperatures at 24 and 48 hours (p < 0.05). Progressive and rapid progressive motility also differed significantly at 24 hours (p < 0.05). Sperm viability showed statistical differences across thawing groups at 24 and 48 hours (p < 0.05), while morphological abnormalities were significant at 12 and 48 hours (p < 0.05). Across all groups, sperm quality parameters varied significantly at each time point (p < 0.05).

Discussion

Thawing at 37°C and storing at 4°C for up to 24 hours optimizes sperm motility and viability, minimizing cryodamage and ensuring functional preservation. This approach is effective for short-term storage and crucial for sustaining genetic diversity and fertility in poultry breeding programs.

Apigenin supplementation substantially improves rooster sperm freezability and post-thaw function

This pioneering research investigated apigenin potential to augment rooster sperm cryosurvival in an extender model. Apigenin is a natural antioxidant flavonoid showing promise for improved post-thaw sperm function. However, its effects on avian semen cryopreservation remain unexplored. This first study supplemented rooster sperm Lake extender with 0, 50, 100, 200, 400 μmol/L apigenin to determine the optimal concentrations for post-thaw quality. Supplementation with 100 μmol/L apigenin resulted in significant enhancements in total motility (from 41.5% up to 71.5%), progressive motility (18.1% to 29.1%) (p < 0.05), membrane integrity (40% to 68%), mitochondrial function (p < 0.001), viability (37% to 62%) and total antioxidant capacity (p < 0.001) compared to the control. It also substantially reduced percentages of abnormal morphology, reactive oxygen species and apoptosis (p < 0.001). Although 200 μmol/L apigenin significantly enhanced some attributes, effects were markedly lower than 100 μmol/L. Higher doses did not improve cryoprotective parameters. This indicates 100 μmol/L as the optimal apigenin concentration. This represents the first report of apigenin protecting rooster sperm from cryodamage. The natural antioxidant improved post-thaw sperm quality, likely by suppressing oxidative stress and apoptosis. Apigenin shows promise for enhancing rooster sperm cryosurvival.