| Popis: |
The aim of the study was to improve cryopreservation of young bulls’ semen. Bioxcell and Tris extenders were modified by adding α-linoleic acid (ALA) or linoleic acid albumin (LAA). Non-modified Bioxcell extender was used as control. Semen diluted in modified, glycerol-free Tris extender was subjected to a longer equilibration (26-28 hours at +4°C). Thirty-one ejaculates collected from 12 bulls aged 12-17 months were used in this research. After collection, fresh semen was divided into 7 portions, and each portion was diluted in one of experimental diluents, as well as in the control diluent. After equilibration, semen was frozen in a freezer. Subsequently, the semen was thawed and its motility was assessed (approximately and by CSA) along with cell membrane integrity (SYBR-14 and PI). The highest motility was observed in Bioxcell diluent supplemented with α-linoleic acid (ALA), and it was significantly higher (p ≤ 0.5) than in Bioxcell diluent (control). No significant differences in cell membrane integrity were observed between experimental groups that were subjected to a 2.5 hour equilibration. The extension of the equilibration time to 26-28 hours caused a significant (p ≤ 0.01) decrease in both the motility and the cell membrane integrity of spermatozoa compared to semen frozen in Bioxcell diluent (control) as well as to all other experimental diluents. In the case of semen that did not meet qualitative standards (motility below 50%) when frozen in the control diluent, significantly better results (p ≤ 0.01 and p ≤ 0.05) in terms of motility (assessed approximately and by SCA) were observed when the semen was diluted in Bioxcell diluent supplemented with α-linoleic acid (ALA) as well as in Bioxcell diluent supplemented with linoleic acid albumin (LAA) (p ≤ 0.05). No significant differences in cell membrane integrity were observed. The extension of equilibration time caused a significant (p ≤ 0.01) decrease in both the motility and the cell membrane integrity of spermatozoa. The study confirmed the possibility of improving cryopreservation of young bulls’ semen by modification of freezing diluents. |
