Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 28, 2003
Publication Date: N/A
Interpretive Summary: Little is known about the ways in which bird sperm cells respond to changes in solute concentration that occur during a freeze/thaw cycle. Because fewer than 2% of inseminated frozen/thawed sperm are capable of fertilization, it is clear that sperm function is somehow compromised during the cryogenic cycle. The overall aim of this study was to compare two species (domestic turkey and sandhill crane) for the response to solute changes during the cryogenic cycle. Distinct species difference were observed, with turkey sperm being much more sensitive to the change in solute concentration than crane sperm. Additionally, modification of membrane ionic pumps appeared to reduce this sensitivity in turkey semen, showing promise for incorporation into new cryopreservation procedures.
An experiment was conducted to evaluate the sensitivity of crane and turkey spermatozoa to hyperosmotic conditions similar to those encountered during a cryogenic cycle. Sperm from both species were exposed to hypertonic media ranging from 500-3000 mOsm (300 mOsm = isotonic) for differing lengths of time (2, 10, 25, 60 min and 4h) at 2 different temperatures (21 and 4C). Sperm viability was determined using the eosin-nigrosin stain. Overall, turkey sperm were more sensitive to hypertonic conditions than crane sperm, regardless of temperature or the presence of cryoprotectant. Interestingly, turkey sperm responded positively to both ouabain and amiloride-induced modification of membrane ionic pumps, with 62-70% viable sperm under hyperosmolar conditions, compared to 20-34% in control samples. Data presented here shed new light on a possible approach for improving turkey sperm survivability after cryopreservation.