Freezability of Andalusian donkey (Equus asinus) spermatozoa: effect of extenders and permeating cryoprotectants

Abstract

The aim of this study was to compare the effect of two semen extenders and four permeating cryoprotectants on post-thaw sperm quality of Andalusian donkeys. First, 32 ejaculates were pooled, split and frozen in either Gent B or INRA 96 with egg yolk and glycerol. Second, 12 pooled semen samples were simultaneously frozen in Gent B (glycerol) or Gent A containing ethylene glycol (EG; 1 or 1.5%) or dimethyl sulfoxide (DMSO; 1.5 or 2%). Finally, nine pooled samples were simultaneously cryopreserved in Gent A containing 1% EG (as control), dimethylformamide (DMFA; 1 or 2.5%) or a combination of 1% EG and 1.5% DMFA. Gent B yielded a higher (P<0.01) post-thaw sperm motility than modified INRA96. EG 1% increased the sperm membrane integrity (P<0.001), whereas DMSO affected sperm motility and membrane integrity (P<0.001). DMFA 2.5% yielded higher (P<0.001) values for sperm motility and membrane integrity. We concluded that Gent B improves in vitro post-thaw sperm quality of donkey spermatozoa, but the replacement of glycerol with 1% EG or 2.5% DMFA increased sperm protection against cryodamage. The use of DMSO for freezing donkey semen was unsuccessful and a toxic effect is suspected. These extenders should be included in the pre-freeze test for each donkey.

Influence of partial or total replacement of glycerol by alternative cryoprotectants in Ghent freezing extender on post‐thaw sperm quality in stallions

“…This combination was chosen because in preliminary experiments it proved to be promising, while all other combinations of cryoprotectants without glycerol were unable to maintain equine semen quality during freezing and thawing. The fact that complete removal of glycerol from the freezing extender is not beneficial for semen quality during cryopreservation is in agreement with earlier studies (Acha et al, 2016;Forero-Gonzales et al, 2012;Malo et al, 2012;Moore, Squires, Bruemmer, & Graham, 2006;Squires et al, 2004). However, the combination used in the present investigation provided at least some cryoprotective effects.…”

Efecto de la suplementación del diluyente sobre la calidad del semen de asno a la descongelación

“…Estos resultados coinciden con lo encontrado por Acha et al (2015), quienes describieron mejores resultados con DMF respecto al GLY (ambos suplementados al 2,5%), para la movilidad y la integridad de membrana del semen criopreservado de asno andaluz. Gibb et al (2013) atribuyeron los mejores resultados post-descongelación de la DMF, a la posible reducción del estrés osmótico ejercido en los espermatozoides, toda vez que su menor peso molecular favorece su paso más libre a través de la membrana.…”

“…Entre las principales alternativas, la dimetilformamida (DMF) es conocida por su efecto crioprotector en semen equino, que se atribuye a su menor toxicidad y su mayor capacidad de difusión a través de la membrana de los espermatozoides (Alvarenga et al, 2005), debido a su menor peso molecular. En un estudio reciente, se describió un efecto positivo de la DMF sobre la movilidad y la integridad de membrana de espermatozoides criopreservados de la raza asnal andaluza (Acha et al, 2015).…”

Alternatives in Donkey semen cryopreservation: Mare vs. Jenny Colostrum

“…Frozen donkey semen, in comparison to horses’, shows low conception rates after artificial insemination (33%–56% mares vs. 0%–36% jennies). In addition, there are only few studies about donkey semen cryopreservation (Acha et al., ).…”