Cryopreservation of Giraffe Epidydimal Spermatozoa Using Different Extenders and Cryoprotectants

Abstract

Giraffe numbers have plummeted over the last 30 years by 30–40%. Thus, their conservation status has been raised from least concern to vulnerable. Efforts to manage in situ and ex situ populations are increasing. Assisted reproduction techniques (ART) such as sperm cryopreservation could help preserve the genetic diversity of giraffe subspecies and, when used for artificial inseminations, enhance genetic exchange between isolated populations. However, to date, the post-thaw motility of recovered sperm has been low and inconsistent. In this study, epididymal sperm collected from the testes of giraffes (n = 7) was frozen in three different extenders, namely, BotuCrio, Steridyl, and test egg yolk (TEY), each supplemented with one of two different cryoprotectants (5% glycerol or a mix of 1% glycerol and 4% methylformamide) and frozen over liquid nitrogen vapor. Across all three extenders, sperm showed significantly better post-thaw results when frozen with a mix of glycerol and methylformamide compared with glycerol alone. Sperm frozen with TEY and a mix of glycerol and methylformamide achieved superior post-thaw total and progressive sperm motility of 57 ± 3% and 45 ± 3%, respectively. These results show the benefit of using alternative cryoprotectants for freezing giraffe spermatozoa and could aid in the application of ARTs for giraffe subspecies or the closely related endangered Okapi.

Pesquisa Multidisciplinar em Saúde - Edição IX

“…Essa abordagem oferece uma alternativa ao congelamento com glicerol tóxico, potencialmente melhorando a motilidade pós-descongelamento. Utilizando indivíduos híbridos criados em cativeiro como modelo, esse método é crucial para aprimorar protocolos de preservação genética e promover a sobrevivência de subespécies de girafas ameaçadas no futuro (HERMES, 2022).…”

Retrograde Flushing Followed by Slicing Float-Up as an Approach to Optimize Epididymal Sperm Recovery for the Purpose of Cryopreservation in Equids

“…In the early 2000s, a wider acceptance of artificial insemination by many horse breeds and advances in semen processing led investigators to turn their focus on epididymal sperm cryobiology. In recent years, epididymal sperm harvesting and cryopreservation evolved remarkably and are widely used in all domesticated mammals [ 3 , 4 , 5 , 6 , 7 , 8 ] and have also been recently applied to captive and non-domesticated species such as giraffes [ 9 ], rhinoceros [ 10 ], and giant pandas [ 11 ].…”