Protective effect of trehalose on canine spermatozoa in Cryopreservation

Cryopreservation of canine spermatozoa allows to preserve male genetic materials and contributes to conserve genetic materials of superior males or extinct animals in breeding management by using the frozen spermatozoa at time needed. However, spermatozoa may undergo multiple steps of possible damage during cryopreservation such as ice crystal formation. The semen extender is composed of buffer, saccharide, cryoprotectant and antibiotics which provide an optimal milieu for spermatozoa. Here, trehalose was treated in the semen extender that was used to freeze freshly collected canine semen, and the effect of trehalose on sperm motility and acrosome integrity were investigated based on different thawing and post thawing incubation conditions. The sperm motility was evaluated by CASA, and the frozen-thawed sperm motility was significantly higher than that in 44 mM glucose treatment group (MOT, ALH and MAD). Thawed sperms in trehalose treatment group maintained their motility at various thawing temperature (P < 0.05). During post-thawing incubation periods the frozen-thawed sperms' motility was reduced in time manner (0-8 h). However, the addition of trehalose in semen extender enhanced the stability of sperm motility significantly compared to the 44 mM glucose treatment during post-thawing incubation. In addition, trehalose treatment contribute to maintain intact acrosomes of sperms during thawing and post-thawing incubation effectively. In conclusion, the treatment of trehalose to semen extender reduced the damage of sperm motility and acrosomes which are related to the fertile quality of the frozen-thawed spermatozoa. Therefore trehalose would be a feasible supplementation to protect sperms to maintain their fertile ability during cryopreservation.