Penetration of zona-free hamster oocytes by ejaculated cryopreserved gorilla spermatozoa.

Semen obtained by electroejaculation from two lowland gorillas were cryopreserved in TEST yolk to evaluate the ability of spermatozoa to penetrate zona-free hamster oocytes. Thawed semen was processed through a two-layer Percoll density gradient to obtain motile spermatozoa for the SPA. The processed sperm penetrated greater than 25% of the zona-free hamster oocytes. Thus, the use of TEST yolk to cryopreserve gorilla semen and processing the thawed semen through Percoll gradient to concentrate motile spermatozoa may facilitate sperm capacitation and the ability to penetrate oocytes.