RESUMEN
Semen freezing and storing has been widely used in reproductive biotechnology, being applied to certain males of livestock breeds or animal species with economic value such as the Angora goat. The development of a semen extender with the cryoprotective agents can prevent the deterioration of sperm parameters after thawing. This study aimed to investigate lipid mixtures (from a liposome kit, Lps) and melatonin (Mel) at different doses to prevent the deterioration of sperm parameters and to provide the cryoprotective effects on sperm DNA. The Angora goat ejaculates were collected and pooled. They were divided into seven equal volumes, and each of them was diluted with the extenders of the experimental groups with additives (Lps 321.99 µg/mL, Lps 841.33 µg/mL, Mel 0.25 mM, Mel 1 mM, Lps 321.99 µg/mL + Mel 1 mM, Lps 841.33 µg/mL + Mel 0.25 mM) and no additives (control group). After the freeze-thawing process, motility, viability, acrosome integrity, DNA double-strand breaks, and abnormal DNA integrity were assessed for different extender groups. It was determined that the use of Lps alone at low dose or the combination of Lps and Mel had significant cryoprotective effects on motility, viability, acrosome integrity, and DNA damage in Angora goat sperm. This study will help us to understand the effects of Lps and Mel used alone or in combination at different doses and which doses give the optimum spermatological parameter rates following the freeze-thawing process, and hence it will shed light on further studies.
RESUMEN
In the presented study, the effects of ROCK inhibitor Y-27632, antifreeze protein III, and boron at two different doses were investigated on the spermatological parameters of Ankara buck semen after freeze−thawing. Ejaculates were collected from bucks using an electroejaculator during the breeding season. The ejaculates that showed appropriate characteristics were pooled and used in the dilution and freezing of semen. The extender groups were formed by adding two different doses of three different additives (ROCK inhibitor Y-27632, 5 and 20 µM; antifreeze protein III, 1 and 4 µg/mL; boron, 0.25 and 1 mM) to the control extender. The semen was diluted with the different extenders at 35−37 °C and loaded into straws. Sperm samples frozen in liquid nitrogen vapors, following equilibration, were stored in liquid nitrogen. It was observed that extender supplementation improved post-thaw motility of Ankara buck semen after freeze−thawing. Differences were significant (p < 0.01) for 5 and 10 µM doses of ROCK inhibitor (71.82% and 74.04 % motility), as well as for 0.25 and 1 mM doses of boron (76.36% and 72.08% motility), compared to the control group (66.15% motility). With respect to the evaluation of acrosomal integrity and mitochondrial activity after freeze−thawing, although supplementation provided protection at all doses, the efficacy was not statistically significant (p > 0.05). It was observed that DNA damage was improved by antifreeze protein III at 1 µg/mL (1.23% ± 0.23%) and by boron at all doses (0.25 mM: 1.83% and 1 mM: 1.18%) compared to the control group (3.37%) (p < 0.01), following the thawing process. In the present study, it was determined that some additives added to the extender provided significant improvements in buck spermatozoa motility and DNA damage after thawing.
