Criopreservação de espermatozoides epididimários e vitrificação de tecido gonadal de animais silvestres post mortem

Abstract

Roadkill mortality has serious impacts on wildlife, which can affect the population dynamics of many species and therefore increase the risk of local decline or extinction. The objective of this work was to use epididymal sperm retrieval, evaluation and cryopreservation techniques, and to carry out the vitrification of testicular tissue obtained from different species of free-living wild animals that evolved to death, victims of being run over on roads in Mato Grosso. Testicles were obtained from 17 roadkill specimens of different species (Guerlinguetus poiaiae, Cerdocyon thous, Myrmechophaga tridactyla, Cuniculus paca, Alouatta caraya, Potos flavus, Spetothos venaticus, Sapajus apella, Didelfis albiventris, Tapirus terrestris and Mazama gouazoubira), and recovered epididymal sperm using the compression technique. The semen was evaluated for motility, vigor, membrane integrity, acrossome integrity, sperm concentration and sperm morphology, and when possible refrigerated or cryopreserved. In the immediate evaluation (fresh material) of epididymal spermatozoa, motility values ranging from 0 to 80% were observed, and vigor ranging from zero (no apparent vigor) to 4, in addition to viability ranging from 0 to 85%, acrossomal integrity ranging from 0% to 88%, and sperm concentration ranging from 0.5 to 1375 x 106 sperm/mL; in the morphological evaluation, defects were observed in the head, middle piece and tail, with proximal and distal gout being the most common defects. In a specimen of Myrmechophaga tridactyla, in refrigeration the epididymal spermatozoa were viable for up to two hours using Triladyl® or Andromed®. In the cryopreservation, carried out in Cuniculus paca, Potos flavus, Sapajus apella, Tapirus terrestris, Mazama gouazoubira and Myrmechophaga tridactyla, post-thawing motility values varying between 0 and 10% were observed, and vigor varying from zero to 2, in addition to viability ranging from 2 to 11%, acrossomal integrity ranging from 1.5% to 20% using Andromed®; and motility ranging from 0 to 40%, and vigor ranging from zero to 3, in addition to viability ranging from 2 to 22%, acrosomal integrity ranging from 3% to 18% using Triladyl®. In the vitrification of testicular tissue in Cuniculus paca, Allouata caraya, Potos flavus, Speothos venaticus, Sapajus apella, Didelphis albiventris, Tapirus terrestris, and Myrmechophaga tridactyla, tissue damage and structural organization were observed when using vitrification media with and without cryoprotectant (association of Ethylene Glycol and Dimethylsulfoxide), but the germinal epithelium has a more organized appearance in these media compared to the fresh material. It is concluded that it is possible to recover epididymal spermatozoa from the species Guerlinguetus poaiae, Cerdocyon thous, Myrmecophaga tridactyla, Cuniculus paca, Allouata caraya, Potos flavus, Sapajus apella, Tapirus terrestris, and Mazama gouazoubira performing epididymal compression. In the species Cuniculus paca, Myrmecophaga tridactyla, Potos flavus, Sapajus apella, Tapirus terrestris, and Mazama gouazoubira, it was possible to carry out the cryopreservation of this material, where the Triladyl® extender showed superior results when compared to Andromed® in the evaluated species. There was an apparent preservation of germinal epithelium after vitrification of testicular tissue in different species, however, further studies are needed to determine the feasibility of the technique used.