Effect of different dilution rates on total and progressive motility of Bactrian camel spermatozoa

The freezability of Bactrian camel spermatozoa at different dilution rates has not been assessed. In other words, being an important determinant of cryopreservation outcome, the Camelid sperm dilution rate has been mostly studied in liquid storage with contradictory results. The effect of different dilution rates on the motility of Bactrian camel spermatozoa was evaluated in the current study. Semen samples from four healthy adult males were collected, processed, and pooled. They were then subjected to a completely randomized design with four dilution rates (DR; ۱:۱, ۱:۲, ۱:۴, or ۱:۸; v:v with SHOTOR diluent). After freezing and thawing, total and progressive motility of spermatozoa were assessed. For analyzing the motility parameters, sperm samples were incubated after thawing in a water bath at ۳۷ °C for ۵ min. Five μL of semen was placed directly on a pre-warmed microscope slide, covered with a cover slip. The sperm motility characteristics were determined using a phase contrast microscope with computer-assisted semen analysis (CASA) software. In a more detailed analysis, sperm total motility percentage was significantly higher in samples with fourfold dilution (۳۹.۵۸%) than in both the lowest (۳۱.۸۳%) and the highest (۳۳.۳۳%) diluted samples. Likewise, the ۱:۴ dilution rate significantly improved sperm progressive motility percentage compared to other dilution rates (۱۹.۵۰ vs ۱۴.۰۰, ۱۶:۰۰, and ۱۴.۲۵ for ۱:۴, ۱:۱, ۱:۲, and ۱:۸ DR, respectively). The study aimed to examine the effect of varying dilution rates on post-thaw quality of Bactrian camel spermatozoa. A fourfold dilution rate resulted in more favorable results regarding sperm motion parameters; however, lower dilution of spermatozoa before freezing led to poor post-thaw quality parameters. It is proposed that increasing semen concentration, especially in animals with lower freezability of spermatozoa, can compensate for the quality loss during cryopreservation. A four-fold dilution alone can be an optimal procedure to cryopreserve Bactrian camel sperm.

کلیدواژه ها:

Bactrian camel ، Cryopreservation ، Dilution rate ، Motility ، Spermatozoa