The In Vitro Evaluation of Rooster Semen Pellets Frozen with Dimethylacetamide

Sperm cryopreservation is an effective technique for conserving animal genetic diversity and transmitting superior genetic backgrounds, maintained via a non-invasive sampling and collection of huge quantities of sperm. Nevertheless, cryopreservation in avian species is not commercially viable because of the rooster sperm ' s susceptibility to damage. This study aims to estimate the impact of dimethylacetamide (DMA) as a cryoprotectant at different levels (3%, 6%, or 9%) on the post-thawed sperm quality, motility, antioxidant-biomarkers, and the expression of anti-freeze related genes. Semen samples were collected twice a week from twelve roosters aged 40 wk, weighing 3400 +/- 70 g, and belonging to the Cairo-B2 chicken strain. Fresh semen samples were rapidly appraised, pooled, diluted with two volumes of a basic extender, and divided equally into three groups. The diluted groups were chilled at -20 C-circle for 7 min, then gently supplemented with 3, 6, or 9% pre-cooled DMA and equilibrated at 5 C-circle for a further 10 min. Semen pellets were formed by pipetting drops 7 cm above liquid nitrogen (LN2), which were then kept inside cryovials in the LN2. Thawing was performed 2 months later by taking 3-4 pellets of the frozen semen into a glass tube and warming it in a water bath for 8 s at 60 C-circle. The results showed that 3% DMA increased the proportion of total motile sperm, progressivity, viability, and plasma membrane integrity (%) compared to the 6% and 9% DMA groups. The lipid peroxidation and antioxidant enzyme activity were improved in the 3% group. At the same time, some anti-freeze-related genes '(including ras homolog family member A (RHOA), heat shock protein 70 (HSP70), and small nuclear ribonucleoprotein polypeptide A (SNRPA1)) expressions were upregulated within the 3% DMA group relative to other groups. In conclusion, the 3% DMA group maintained higher post-thawed sperm quality than the other tested groups.

Automated summary

This study aims to evaluate the impact of different concentrations (3%, 6%, or 9%) of dimethylacetamide (DMA) as a cryoprotectant on post-thawed sperm quality, motility, antioxidant-biomarkers, and the expression of anti-freeze related genes. The results showed that 3% DMA group maintained higher post-thawed sperm quality compared to the other tested groups, with improvements in motility, viability, and antioxidant enzyme activity. Additionally, certain anti-freeze related genes were upregulated in the 3% DMA group.