Effects of cryopreservation on sperm structure in Japanese pearl oyster Pinctada fucata martensii
Article first published online: 5 OCT 2008
© 2008 Japanese Society of Fisheries Science
Volume 74, Issue 5, pages 1069–1074, October 2008
How to Cite
NARITA, T., KAWAMOTO, T., ISOWA, K., AOKI, H., HAYASHI, M., OHTA, H. and KOMARU, A. (2008), Effects of cryopreservation on sperm structure in Japanese pearl oyster Pinctada fucata martensii. Fisheries Science, 74: 1069–1074. doi: 10.1111/j.1444-2906.2008.01626.x
- Issue published online: 5 OCT 2008
- Article first published online: 5 OCT 2008
- Received 28 May 2007. Accepted 3 April 2008.
- pearl oyster;
To clarify factors reducing the motility and fertility of cryopreserved spermatozoa of the Japanese pearl oyster Pinctada fucata martensii, the structure of spermatozoa before and after cryopreservation was observed by scanning electron microscopy. Testicular spermatozoa were diluted with cryopreservation diluent (10% methanol + 18% fetal bovine serum + 72% sea water), and dispensed into 0.25-mL straws. The straws were cooled at a rate of approximately −20°C/min to −50°C, and subsequently immersed in liquid nitrogen. Percentage motility of spermatozoa before cryopreservation was 69.9 ± 4.2%, and that of cryopreserved spermatozoa was 24.0 ± 1.8%, respectively. In cryopreserved spermatozoa, the percentage that lacked or had a deformed flagellum was 56.6 ± 3.9%, while in fresh spermatozoa this was 8.7 ± 2.0%. In cryopreserved spermatozoa, the percentage of deformed acrosomes was 76.6 ± 5.2%, while in fresh spermatozoa this was only 0.9 ± 0.3%. Cryopreserved spermatozoa with a normal acrosome and flagellum were only 15.4 ± 3.5% of those in fresh spermatozoa. These results indicate that lesion of the flagellum and deformation of the acrosome occurred through the cryopreservation procedure, and both types of damage lead to loss of the motility and fertility in thawed spermatozoa.