[Objective] This study aimed to investigate the effects of cryopreservation on the quality and ultrastructure of Tibetan Mastiff sperm. [Method] The effects of cryopreservation on the quality of Tibetan Mastiff sperm were evaluated via motility, membrane integrity rate and acrosome intact rate. On that basis, the effects of cryopreservation on ultrastructure of sperm were observed under SEM and TEM. [Result] In Experiment 1, EG gave the best results not only in post-thaw motility rate （36.3%）, but also in low membrane integrity rate （38.0%） and acrosome intact rate （42.0% ）, but there was no significant difference between EG group and Glycerol group （P0.05）. In Experiment 2, the 5 cm freezing height obtained the best freezing-thawing results, but there was no significant difference between 2 and 5 cm height （P 0.05）, besides in acrosome intact rate. In Experiment 3, SDS and Vc added separately or together into extenders could improve freezing-thawing results, but there was not obvious difference between SDS group and Vc group （P0.05）, besides the lower motility of Vc group （P0.05）. Addition of SDS and Vc obtained the best results in post-thaw motility rate （44.1%）, and also in membrane integrity rate （48.0%） and acrosome intact rate （48.2%）. The ultrastructure of frozen-thawed sperm was also evaluated under SEM and TEM, results showed that cryopreservation caused various degrees of damage to Tibetan Mastiff sperm, more serious damages were observed in the acrosome such as swelling, vesiculation and even disappearance. [Conclusion] This study confirms that EG, horizontal height of 0.25 ml straw above LN 2 surface and additives SDS and Vc together can improve freezing effect. However, cryopreservation has certain damage to ultrastructure of sperm.
To explore the correlation of evaluation methods on boar semen quality, the motility, PI staining, hypotonic swelling test, Rh123 staining and FITC- PNA staining of boar sperm were checked in the study, and its correlation with IVF was statistically calculated. The results showed that various indicators had strong linear correlation with each other, and the correlation degree between acrosome integrity and IVF rate was the highest, indicating that acrosome integrity was supedor to other indicators in predicting IVF rate.
The paper was to explore the effect of cryopreservation on DNA integrity and morphological structure of boar sperm, and to explore the protective effect of trehalose and lactose on frozen boar sperm. The morphology, ultrastructure and DNA integrity of sperms were observed by phase contract microscope, scanning electron microscope （SEM） and acridine orange （AO） staining, respectively. The results showed that the normal morphological rate and DNA integrity rate of fro- zen sperms were significantly lower than that of fresh sperms （95.5% and 94.7%, respectively）, and the difference between two frozen groups was also significant （P 〈 0.05 ）. The normal morphological rates in trehalose group and lactose group were 74.7% and 67.6%, while DNA integrity rates in trehalose group and lactose group were 66.4% and 63.2%, respectively. The common deformations of frozen sperms under SEM were partial or complete fracture between head and neck, swollen neck_ dama=ed aemsome stnJetn~.
Yang JianpingWu CaihongZhao XutingZhou ChunbaoYao JingZhang BinZheng Xiaofeng
