Effect of two freezing extenders on characteristic of fresh and frozen-thawed semen in endangered Old Kladruber stallions - A pilot study

Abstract

ABSTRACTŠichtař J., Nehasilová A., Šimoník O., Bubeníčková F. (2017): Effect of two freezing extenders on characteristic of fresh and frozen-thawed semen in endangered Old Kladruber stallions -A pilot study. Czech J. Anim. Sci., 62, 227−233.The aim of the study was to evaluate the effect of two different extenders on sperm characteristic before equilibration and post-thaw in the endangered Old Kladruber stallions. Also, the response of individual stallions to the extenders used was tested. Semen was collected from six stallions every other day within one week. After centrifugation of the collected sperm-rich fraction, the supernatant was removed and sperm pellets were divided to two aliquots; these were diluted either with Gent (Minitube, Germany) or privately manufactured lactose-EDTA-egg yolk extender (Lact). Three cryopreserved insemination doses (IDs) from each extender (Gent and Lact) were prepared for each stallion from one collection (108 samples from six stallions in total). As a parameter of quality, the motility (computer assisted sperm analysis), viability (fluorescence staining), and morphology (eosin/nigrosine staining) were evaluated after dilution with freezing extenders (fresh) and after thawing (frozen-thawed). The different effects of chosen extenders on the quality of fresh semen were only manifested in higher kinematic parameters of sperm when the Lact extender was used. However, in frozen-thawed samples, the Gent extender yielded significantly better results in all of the evaluated parameters. The representation of sperm subpopulation was significantly influenced by extender in fresh as well as frozen-thawed samples; moreover, we found a significant effect of freezing on the distribution of these subpopulations. The response of individual stallions to chosen extenders was evident in the different quality of fresh as well as frozen-thawed IDs; Gent extender yielded better frozen-thawed IDs. Based on our results, among others describing quality parameters of ejaculate in endangered Old Kladruber stallions, we can recommend using Gent extender for the production of frozen-thawed IDs.

Low Density Lipoprotein - important player in increasing cryoprotective efficiency of soybean lecithin-based bull semen extenders

“…Concerning the results of percentages of progressively motile spermatozoa (PMOT), the effect of LDL was not demonstrated in either extender.This clearly shows the general character of this parameter, however it also demonstrates generally suitable quality of all specimens. Indeed, cluster analysis is widely accepted by the researcher community as a method reflecting the heterogeneity of sperm population in samples (Martinez-Pastor et al, 2011); thereby it pointed out more precisely the response of cells to modified conditions during cryopreservation (Holt et al, 2004;Muino et al, 2008;Sichtar et al, 2017) and was able to unveil the more subtle effects of LDL on sperm motility.…”

How to Increase Post-Thaw Semen Quality in Poor Freezing Stallions: Preliminary Results of the Promising Role of Seminal Plasma Added after Thawing

“…In addition to the mentioned effect on kinematic parameters, we also, as with the first study, found a positive effect of the addition of SP on the distribution of spermatozoa into subpopulations. The existence of various subpopulations of spermatozoa in ejaculate is well known, see for example [26,27], and the simple averaging of kinematic parameters may lead to misleading results. Despite this fact, this approach is still lacking/ignored in many studies dealing with specific effects on spermatozoa motility.…”

Effects of Various Incubation Conditions on Functional Parameters of Stallion Spermatozoa

“…The freezing of semen was conducted as previously described by Sichtar et al (2017). Briefly, sperm-rich fractions were pre-diluted with a skim-milk based extender and centrifuged (650 g for 15 min).…”