Evaluación morfométrica de espermatozoides de mamíferos silvestres criopreservados en el banco criogénico de la Universidad de Cuenca

Abstract

Certain evidence suggests that the dimensions of sperm head could indicate their cryosurvival. Damage caused by cryopreservation protocols could be evaluated based on the variation in morphometric dimensions of sperm from wild animals. Therefore, we evaluated the morphometric characteristics of fresh and cryopreserved sperm, specifically the head and midpiece, from white-tailed deer, spider monkeys, and Amazonian tapirs stored in the cryogenic bank at the University of Cuenca. For this purpose, fresh, frozen-thawed, and vitrified-warmed sperm samples were fixed, stained, mounted, and evaluated using the ASMA-CASA system. We assessed the length, width, area, perimeter, ellipticity, elongation, roughness, and regularity of the sperm head, as well as the width and area of the midpiece. Freezing did not alter (P>0.05) the morphometric dimensions of deer and monkey sperm. However, the dimensions of deer sperm head decreased (P<0.05), while the dimensions of monkey sperm head increased (P<0.05) after vitrification compared to their fresh values. The head area of sperm from wild animals was as follows (in µm²): deer (29.8±0.77 vs. 29.7±0.29 and 20.7±0.17, respectively), monkey (14.3±0.33 vs. 14.8±0.25 and 16.3±0.28), and tapir (17.7±0.25). In conclusion, the freezing process did not alter the dimensions of deer and monkey sperm, but vitrification reduced the morphometry of deer sperm head and increased the dimensions of spider monkey sperm head.