Comparison Between Three Cryoprotectants in the Freezing of Mazama americana Semen Collected by Artificial Vagina

Abstract

Maintaining genetic variability is an important part of the conservation of endangered species, so the construction of germplasm banks is essential. Several species of the genus Mazama endure constant pressure in their natural habitat and are threatened with extinction. The correct manipulation and adequacy of the diluents and cryoprotectants must be studied to be successful in the formation of these banks. The purpose of this study was to evaluate the efficiency of three different cryoprotectants in sperm cryopreservation in the species Mazama americana: 6% glycerol (GLY), 3% ethylene glycol (ETG), and 5% dimethylformamide (DMF). Semen was obtained with the lateral deviation of the penis to an artificial vagina. In the pre-freeze and post-thaw periods, motility, vigor, membrane integrity, acrosome integrity, and sperm cell morphology were evaluated for each of the cryoprotectants. Post-thaw motility was higher when semen was frozen with cryoprotectants GLY and DMF (55.31-7.39 and 55.94-2.77, respectively), compared with the result obtained for ETG (48.13-2.39). For major defects (MaD), a difference was observed between the pre-and post-cryopreservation periods, such that DMF generated a higher number of post-thaw MaD (25.94-5.37). All cryoprotectants were efficient for cryopreservation of M. americana semen, resulting in samples with satisfactory viability after thawing. However, the medium with the cryoprotectants GLY, at a concentration of 6%, and DMF, at a concentration of 5%, were preferable.

Chromosomal Polymorphism and Speciation: The Case of the Genus Mazama (Cetartiodactyla; Cervidae)

“…Ejaculate color was determined by a single researcher to avoid any individual biases. Volume, total motility, sperm vigor, and sperm count were evaluated as described by Alvarez et al (2020) [35]. Morphological analysis of the ejaculate was performed through the examination of wet preparations of fixed spermatozoa under phase contrast microscope.…”

Assisted Reproductive Technology in Neotropical Deer: A Model Approach to Preserving Genetic Diversity

“…Using females in estrus as a live mannequin, it was possible to perform the lateral deviation of the penis towards AV, and to obtain the seminal collection in individuals of the genus Mazama (Figure 1A). The success rates vary in the literature, from 75% to 100% in M. gouazoubira [72] and from 50% to 70% in M. americana [72,73]. It is also possible to use imprinted animals for seminal collections by AV, where the males perform the mounts directly on the operator's knee (Figure 1B).…”

“…In a study that sought to determine certain physicochemical and microscopic characteristics of semen of M. americana, the authors described pH and osmolarity of 6.90 ± 0.74 and 297.74 ± 19.10 mOsm/kg respectively, in the ejaculate [82]. These results assisted in choosing the diluents used by Alvarez and collaborators [73], together with substances that were beneficial for seminal cryopreservation of species of the Mazama genus (vitamin E and Equex) to enable the formulation of a medium for better results in the cryopreservation of semen. Thus, different penetrating cryoprotectants (glycerol, ethylene glycol, and dimethylformamide) were tested in tris-citric acid medium, with egg yolk 20% and adding vitamin E and Equex.…”

Freezing Hu ram semen: influence of different penetrating cryoprotectants and egg yolk level on the post-thaw quality of sperm

“…Moreover, when 6% GLY and 6% EG were combined, the toxic effect on sperm significantly increased, leading toresulting in a decrease in the intact rateintegrity of the plasma membrane and acrosome of thawed sperm. This may be because the high concentration of CPAs has altered the osmotic pressure of sperm, leading to sperm damage [2941]. Gonzalez-Castro [3042] found in the study of stallion sperm that the combination of two CPAs has a better effect than using a single CPA.…”