Influence of Temperature during Glycerol Addition and Post‐thaw Dilution on the Quality of Canine Frozen Semen

Abstract

Contents The aim of the present study was to compare the influence of room temperature (27 degrees C) and 4 degrees C during glycerol addition on canine semen cryopreservation and verify the effect of different post-thawing dilutions on canine semen. Ten ejaculates from five stud dogs were collected by digital manipulation. Semen samples were evaluated and further divided into two aliquots. The first aliquot was extended in Tris-egg yolk-glycerol at 27 degrees C and the second one received glycerol at 4 degrees C. Samples were frozen and stored in liquid nitrogen. After 1 week, samples were thawed and submitted to evaluations of progressive sperm motility, morphology, acrosomal integrity, hypo-osmotic swelling (HOST) and thermoresistance tests. For thermoresistance test, aliquots were divided in two portions: one portion was kept undiluted (1 : 0) and the other one was diluted in a 1 : 4 ratio (one part semen to four parts extender). No differences were observed between temperatures for glycerol addition regarding seminal parameters evaluated. Furthermore, post-thawing dilutions demonstrated similar effect on canine semen longevity. Correlations among post-thaw sperm motility and HOST and results from thermoresistance test were observed for both temperatures for glycerol addition. In conclusion, glycerol could be added to canine semen at room temperature (27 degrees C) or at 4 degrees C. Moreover, there is no need to extend canine semen after thawing for the thermoresistance test, but if we need to increase the inseminating volume for artificial inseminations, the addition of extender will not damage the semen.

Evaluation of Fertilizing Potential of Frozen‐thawed dog Spermatozoa Diluted in ACP‐106®using anIn VitroSperm–Oocyte Interaction Assay

“…Silva et al. (2006) using the same freezing protocol with a Tris extender obtained similar results of intact plasma membrane.…”

“…Finally, straws were plunged into liquid N 2 (−196°C) for storage (Cardoso et al. 2004, Silva et al. 2006).…”

“…This solution was composed by 20 ml distilled water, 0.58 g sodium citrate, 0.8 ml phormaldeide and 0.3 g Bengal Rose. Counting 200 cells per slide, sperm morphologic abnormalities were classified as primary and secondary (Silva et al. 2006).…”

Congelación de Semen Epididimal Canino con Yema de Huevo Centrifugada

“…No se observaron diferencias en la movilidad total y progresiva del semen descongelado, ni en la mayoría de los parámetros cinéticos; sin embargo, se encontraron resultados superiores para VCL, VSL y VAP de los espermatozoides epididimales congelados con YHC10 en comparación con el semen congelado con YHC20 (p<0.05). Lo anterior puede ser relevante, toda vez que se conoce que existe una relación favorable entre el incremento de VCL, VSL y VAP con la capacidad fertilizante del semen canino (Silva et al, 2006). No se hallaron reportes previos del uso de YHC en la congelación de semen epididimal canino; sin embargo, en un estudio de Mota et al (2014) se evaluó la congelación de semen epididimal canino con diluyentes suplementados con 10% de YH (ACP-106c) y con 20% de YH (TRIS), encontrando resultados posdescongelación superiores de VSL y STR para el semen criopreservado con 10% de YH.…”

The effect of two packaging systems on the post-thaw characteristics of canine sperm

“…Glycerol is the most popular cryoprotectant for the cryopreservation of canine semen, but it exerts a toxic effect on spermatozoa, in particular at higher temperatures (Martins-Bessa et al 2006). In most semen cryopreservation protocols, glycerol is added at 32-37 o C or at room temperature (Peñ a et al 1998, Rota et al 1998, Silva et al 2006). In our study, the contact between sperm and glycerol was limited by adding glycerol at 5 o C and applying the cryoprotectant at a low final concentration of 4% in the semen-extender mixture for cryopreservation.…”