Abstract
BackgroundRam spermatozoa are sensitive to extreme changes in temperature during the freeze-thaw process. The degree of damage depends on a combined effect of various factors including freezing temperature. The aim of this study was to determine the effects of two cooling method (controlled-rate and uncontrolled-rate) on pre-freezing and post-thaw sperm motility parameters.ResultsEjaculates were collected using the artificial vagina from four Chal rams and three replicates of the ejaculates were diluted with a Tris-based extender and packed in 0.25 ml straws. Then, sample processed according to the two methods. Method 1: straws cooled from 37 to 5°C, at a liner rate of -0.3°C/min in a controlled-rate cooling machine (custom-built) and equilibrated at 5°C for 80 min, then the straws were frozen at rate of -0.3°C/min from 5°C to -10°C and -25°C/min from -10°C to -150°C and plunged into liquid nitrogen for storage. Method 2: straws were transferred to refrigerator and maintained at 5°C for 3 h, then the straws were frozen in liquid nitrogen vapor, 4 cm above the liquid nitrogen for 15 min and plunged into liquid nitrogen. Computer-assisted sperm motility analysis was used to analyze sperm motion characteristics.ConclusionsControlled rate of freezing (Method 1) significantly improve the pre-freezing and post-thaw total and progressive motility compared to uncontrolled rate (Method 2). In specific kinetic parameters, Method 1 gives significantly higher value for VSL and VCL in comparison with Method 2. There are no significant differences between the two methods for VAP and LIN. In conclusion, controlled rate of cooling conferred better cryopreserving ability to ram spermatozoa compared to uncontrolled rate of cooling prior to programmable freezing.
Highlights
Ram spermatozoa are sensitive to extreme changes in temperature during the freeze-thaw process
Considerable effort has been directed towards developing techniques for artificial insemination (AI) using frozen ram semen
The aim of this study was to determine the effects of two cooling methods on pre-freezing and post-thaw sperm motility parameters
Summary
Ram spermatozoa are sensitive to extreme changes in temperature during the freeze-thaw process. The degree of damage depends on a combined effect of various factors including freezing temperature. Considerable effort has been directed towards developing techniques for artificial insemination (AI) using frozen ram semen. Its potential in sheep breeding has become evident following the development of controlled reproduction procedures and more intensive management systems. The widespread application of AI depends largely on the use of frozen semen and on the availability of techniques that result in acceptable fertility in a selective breeding control programme. AI with frozen semen dispensed through the cervix gives quite low fertility rates in ram and use of laparoscopy to -60°C and not during storage in liquid nitrogen [9]. The process of cell dehydration that accompanies slow freezing is potentially beneficial for cell survival, whereas rapid freezing rates are considered more likely to cause cell death [5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
