Influence of freezing techniques and glycerol-based cryoprotectant combinations on the survival of testicular tissues from adult collared peccaries.

The objective of the study was to evaluate the effects of different cryopreservation techniques including glycerol-based cryoprotectant combinations on the structure and viability of testicular tissues from adult collared peccaries. Tissue biopsies (3.0 mm³) from 5 different individuals were allocated to 10 different groups: fresh control; slow freezing (SF), conventional vitrification (CV), or solid-surface vitrification (SSV); each of them using three different combinations of cryoprotectants [dimethyl sulfoxide (DMSO) + ethylene glycol (EG); DMSO + Glycerol; and EG + Glycerol]. After thawing/warming, samples were evaluated for histomorphology, viability, proliferative capacity potential, and DNA integrity. Most effective preservation of testicular histomorphology was achieved using SF and CV with DMSO + EG. However, the use of glycerol-based cryoprotectant combinations increased the occurrence of tubular cell swelling, tubular cell loss and shrinkage from the basal membrane. Cell viability was comparable among cryopreservation methods and cryoprotectant combinations. Regarding cell proliferative capacity, the use of SF with EG + Glycerol and SSV with DMSO + Glycerol impaired the conservation of spermatogonia proliferative potential compared to other treatments. Moreover, CV with DMSO + EG was better than SF with EG + Glycerol for Sertoli cell proliferation potential. Regarding DNA integrity, less damage occurred when using SF with DMSO + EG while more fragmentations were observed when using CV with EG + Glycerol or DMSO + Glycerol as well as SSV with EG + Glycerol or DMSO + Glycerol. In sum, SF and CV appeared to be the most suitable methods for the cryopreservation of adult peccary testicular tissues. Additionally, the use of glycerol-based cryoprotectant combinations did not improve testicular tissues preservation with DMSO + EG being the most efficient option.

Cryopreservation of Spix's yellow-toothed cavy epididymal sperm using Tris- and coconut water-based extenders supplemented with egg yolk or Aloe vera.

Addressing the establishment of biobanks for the conservation of wild hystricomorph rodents' germplasm, we verified the effects of different extenders and distinct concentrations of non-permeant cryoprotectants on the sperm parameters of Spix's yellow-toothed cavies. Nine testis-epididymis complexes were used for sperm collection by retrograde washing using Tris or a powdered coconut water extender (ACP®-116c). Spermatozoa were diluted and frozen with the same extenders supplemented with egg yolk or Aloe vera at a 10% or 20% concentration. After recovery and cryopreservation, all samples were evaluated for sperm kinetic parameters, morphology, membrane integrity, osmotic response, and sperm-binding capability using an egg yolk perivitelline membrane assay. After recovery, no differences were observed between Tris and ACP®-116c that provided 515.4 × 106 sperm/mL and 561.6 × 106 sperm/mL, presenting >65% motile sperm, respectively. After cryopreservation, most effective preservation of sperm kinetic parameters (68.1 ± 5.9% motile sperm) and membrane integrity (48.2 ± 7.4%) was provided by Tris extender supplemented with 10% egg yolk. However, both extenders supplemented with any concentration of egg yolk or Aloe vera presented similar preservation of osmotic response and sperm-binding ability after cryopreservation. In summary, we suggest the use of a Tris extender supplemented of 10% egg yolk for cryopreservation of Spix's yellow-toothed cavy epidydimal sperm.

Reproduction in agouti (Dasyprocta spp .): A review of reproductive physiology for developing assisted reproductive techniques.

Dasyprocta spp. (agouti) include wild rodents with highlighted ecological and economic importance, and are considered experimental models for endangered hystricognath rodents. Of late, development of techniques to conserve their genetic material as well as the formation of biobanks is increasing. In this context, this review describes the main advances in the knowledge of the reproductive morphophysiological specificities of agouti as well as the development and improvement of assisted reproductive techniques aimed at conservation, multiplication, and exploitation of their reproductive potential under captivity.