Effect of freezing and thawing rates on camel sperm quality

Abstract: The objective of this study was to evaluate the effect of different freezing rates and thawing temperatures on the quality of camel spermatozoa post thawing. Ten ejaculates from five male camels were frozen at five different freezing rates, achieved by placing the straws at specific heights above the surface of liquid nitrogen for different times (4 cm for 15 min; 1 cm for 15 min; 7 cm for 15 min; 7 cm for 5 min + 4 cm for 3 min; 4 cm for 5 min + 1 cm for 3 min) followed by storage in liquid nitrogen. Two thawing temperatures (60°C for 10 sec or 37° for 30 sec) were subsequently tested. The sperm samples were evaluated for total and progressive motility, kinematics, membrane and acrosome integrity and membrane functionality zero, one and two hours post thawing. Camel sperm showed a high tolerance for freezing rates with small differences between the different freezing rates. Significantly (p<0.05) better values for sperm characteristics were obtained from the fastest freezing rate compared to a slower rate for total and progressive motility and some kinematic parameters, but no treatment was found to be significantly better for all parameters of sperm quality. However, post thaw sperm quality was better with the faster thawing rate compared to the lower rate. No interactions between freezing and thawing rates were found in the study. In conclusion, according to this study, a fast freezing rate may be more beneficial for camel spermatozoa than slower freezing rates, and the thawing should be conducted at 60°C.