Cryogenic Preservation of Xenopus Sperm.

Cryopreservation of Xenopus sperm offers several advantages: it reduces the number of live animals needed and maintained for in vitro fertilization, enables efficient archiving of genetically altered lines, and facilitates easy transfer between laboratories, lowering animal suffering and overall costs. Sperm freezing and in vitro fertilization using frozen sperm are simple procedures that require only standard laboratory equipment. Testes are macerated in Leibovitz L-15 medium, combined with a cryoprotectant made from egg yolk and sucrose and slowly frozen overnight in a polystyrene box at -80°C.