Rita de Cássia Soares Cardoso

Quality of canine semen submitted to single or fractionated glycerol addition during the freezing process

Glycerol is the cryoprotector most frequently used to freeze semen from different species. The objective of the present study was to compare the effect of single and fractionated glycerol addition on canine semen quality after thawing. Sperm fractions from 12 stud dogs were collected, evaluated, extended in Tris plus egg-yolk and separated into two aliquots to which glycerol was added in one step (single) or in three steps at 5-min intervals (fractionated). Semen was frozen and stored in liquid nitrogen and thawed after 1 week. A thermoresistance test was performed over a period of 120 min at 37-39 degrees C to evaluate the percentage of mobile spermatozoa (motility) and the status of motility (vigor) after thawing. There were no significant differences between the two methods of glycerol addition-immediately after thawing, and during the thermoresistance test-in sperm motility, vigor or morphology. A significant reduction in motility and vigor was found at 15 min after thawing and these parameters continued to decline until 120 min. In conclusion, glycerol can be added to canine semen in single or fractionated manner, but the single addition method is the easiest and the most practical to use.

Cryopreservation of canine semen using a coconut water extender with egg yolk and three different glycerol concentrations

Semen was collected by digital manipulation from six adult dogs. The second fraction of the ejaculate was used in this study. The semen was assessed by macroscopic and microscopic criteria 1 min after collection, first dilution, cooling, glycerol addition and thawing. Experiments were conducted to compare the effect of three different concentrations of glycerol in coconut water extender. The freezing method employed was that one described for caprine semen with slight changes. Semen was thawed at 37 degrees C for 1 min. Spermatozoal motility after thawing was 49.2+/-26, 44.2+/-18.3 and 35.8+/-26.8% for groups with 4, 6 and 8% glycerol, respectively. The vigor after thawing was 2.6+/-1.1, 2.7+/-1.0 and 2.1+/-1.2 for these groups, respectively. There was no difference among groups in motility and vigor. However, a smaller percentage of total and secondary abnormalities was observed using 6% glycerol in coconut water extender. In conclusion, the three glycerol concentrations (4, 6 or 8%) can be used successfully in cryopreservation of canine semen using a coconut water extender.

Congelação de sêmem canino com diferentes concentrações de gema de ovo e glicerol em diluidores à base de tris e água de coco

The aim of the present research was to compare the efficiency of coconut water and Tris extenders on canine semen freezing. The semen from 5 German Shepherd dogs was collected by digital manipulation. The spermatic fraction of different dogs was evaluated about its macro and microscopic parameters and mixed in a pool. It was extended in coconut water or Tris, added of egg yolk (10 or 20%) and glycerol (4, 6 or 8%). Then, it was frozen by the method of NUNES et al. (1997) and thawed at 37oC after one week. A Tris extender superiority was shown at the conservation of vigor (2.3 ± 0.8), total (14.8 ± 5.1%) and secondary (14.4 ± 5.5%) spermatic defects in the protocols with 20% of egg yolk and 6% of glycerol. In all other protocols, there were no significant differences for the observed parameters. These results suggest a superiority of Tris extender over the coconut water extender on canine semen freeze, in the use of them added of 20% of egg yolk and 6% of glycerol.

Criopreservação de sêmen canino com um diluidor à base de água de coco

The long-term storage of frozen semen represents a tool for breeders that want to preserve the genetic potential of their sires. The aim of this experiment was to evaluate the effect of coconut water, egg yolk and glycerol on canine semen cooling and freezing. The sperm rich fraction of 12 dogs was submitted to macroscopic and microscopic evaluation. This fraction was divided into four aliquots and frozen with coconut water extender regarding the presence of egg yolk and glycerol. After cooling, there was no difference among groups. However, after thawing, coconut water plus egg yolk and glycerol (ACGG) was superior than others concerning to sperm motility, vigor and morphological abnormalities. In this group, motility (%), vigor (0-5) and abnormalities (%) were 56.7 ± 16.1, 3.4 ± 0.5 e 23.8 ± 8.4, respectivelly. In conclusion, it is necessary to add egg yolk and glycerol to the coconut water extender to improve the cryopreservation of canine semen.

CONSERVAÇÃO DO SÊMEN CANINO A 37ºC EM DILUENTES À BASE DE ÁGUA DE COCO

The aim of this study was to evaluate the canine semen diluted with coconut water extender, added of 3-indol acetic acid (IAA) and egg yolk at 37oC. Sperm of six stud dogs was collected by digital manipulation and divided in three equal aliquots. Dilution was performed by the addiction of coconut water (extender 1), coconut water plus 4% of IAA (extender 2) and coconut water plus 4% of IAA and 20% of egg yolk (extender 3). Sperm motility, vigor and morphology immediately after dilution and periodically until 180 minutes, as well as media degradation motility rate (DMR), were evaluated. Extenders were compared by Whitney-Mann test (P<0.05). Statistical differences were not shown between the extenders up to 60 minutes. After 90 minutes, sperm motility on the extender A was superior to the other extenders (95%). The DMR on the extender A (7.5%) was significantly inferior to the other extenders. Thus, coconut water extender is adequate for the preservation of canine semen at 37oC for 180 minutes.