Cryopreservation of European eel(Anguilla anguilla)sperm using different extenders and cryoprotectants

Abstract

Experiments were carried out on the sperm cryopreservation of artificially induced eels. The effects of several extenders and two cryoprotectants on the motility of spermatozoa were investigated. The highest post-thaw motility was observed with the combination of Tanaka's extender and DMSO as cryoprotectant. Further dilution after thawing resulted in complete loss of motility in samples frozen in presence of DMSO while sperm frozen with methanol as cryoprotectant retained its motility after further dilution.

Study of male reproductive physiology and sperm conservation in the european EEL ( Anguilla anguilla, L.)

“…One injection is enough to promote the spermatogenesis (Miura et al, 1991a), but the number of animals with complete gonad development was higher with repeated injections . Also, hCG injections have been used in European eel Billard andGinsburg, 1973, Meske 1973;Colombo et al, 1987;Amin 1997;Szabó et al, 2005), but only tested five different treatments with hCG looking for the optimization of the hormonal induction. Fish treated with only three weekly injections, or weekly injected only until the onset of spermiation did not show good results in terms of sperm production, but the treatment that provided best results was weekly injections of 1.5 IU hCG/g fish, that caused the highest percentage of spermiating males and the highest number of sperm samples with high quality.…”

“…Trying to improve the unresolved control on the reproduction of this species, different methods to preserve the sperm were developed depending on the time of conservation required. For short-time storage the sperm can be diluted in a medium that conserves unchanged the sperm characteristics Izawa 1995, 1996;Aurich et al, 1997;Peñaranda et al, in press), while for long-time conservation it is necessary to use cryopreservation techniques , Szabó et al, 2005Marco-Jiménez et al, 2006;. In European eel, any diluent has been developed to preserve the fresh sperm during several days with high motility, and when the sperm was frozen by cryopreservation techniques the best post-thawing motility achieved by our group was 22.2 ± 1.5%.…”

“…Different media and methods have been recently developed for European eel sperm , Szabó et al, 2005Marco-Jiménez et al, 2006;, which are based in previous studies in the Japanese eel species . To design the freezing medium, it is necessary to consider the effect of cryoprotectants on the sperm.…”

“…Szabó et al (2005) . Post-thawing samples in P1 modified medium with DMSO and FBS (25%) showed a significantly higher percentage of motile spermatozoa (22.2±1.5%) that in the rest of conditions.…”

Inducción hormonal de la espermiación y criopreservación de esperma en anguila europea (Anguilla anguilla).

“…Entre los trabajos desarrollados en anguila europea se encuentran resultados significativos en cuanto a los medios de congelación y los crioprotectores más eficientes. Destacan tanto el uso del DMSO Müller et al 2004) y del metanol (Szabó et al 2005). obtuvieron buenos resultados en anguila europea sumando los efectos crioprotectores del DMSO y la L-α-fosfatidilcolina en diluciones 1:5 y 1:100 con distintas soluciones.…”