bachelorThesis
Evaluación de la capacidad fecundante de espermatozoides equinos previamente congelados con Dimetilformamida, glicerol y su combinación, mediante fecundación in vitro heteróloga
Fecha
2022-12-12Autor
Sacaquirin Rivadeneira, Adriana Estefanía
Pillacela Zhunio, Juan Gabriel
Institución
Resumen
Heterologous in vitro fertilization (IVF) using zona-intact bovine oocytes has been
successfully used to assess the fertilizing capacity of stallion sperm. Therefore, this work
evaluated the fertilizing capacity of equine spermatozoa previously frozen with DMF (5),
GLY (5%), and their combination DMF-GLY (3%-3%) by heterologous IVF. In a first
experiment thawed equine sperm samples (DMF, n=90, GLY, n=82 and DMF-GLY, n=84)
and evaluated the kinetic parameters and integrity of the plasma and acrosomal
membranes using a CASA system (SCA-Evolution® 2018) and the PI/PNA-FITC double
fluorescent test, respectively. Subsequently, a heterologous IVF was used in a second
experiment to evaluate the fertilizing capacity of the frozen-thawed semen measured in
sperm-oocyte bound, penetration, and pronuclei formation. For this, frozen equine sperm
with the three cryoprotectants and zona-intact bovine oocytes were used: DMF (n=258),
GLY (n=214) and DMF-GLY (n=240) in 15 sessions. The results showed that the DMFGLY combination was more effective in cryoprotecting equine spermatozoa and producing
higher values (P<0.05) of total (MT) and progressive (MP) motility, curvilinear velocity
(VCL), amplitude of lateral head displacement (ALH), beat-cross frequency (BCF), and
integrity of plasma and acrosomal membranes compared to GLY. However, the fertilizing
capacity of equine spermatozoa frozen with DMF-GLY was similar (P>0.05) to that
obtained in those samples frozen with DMF or GLY. In conclusion, the combination of
DMF-GLY is effective to cryopreserve equine sperm due to achievements obtained in
kinetic and integrity of sperm membranes, but its fertilizing ability was similar to that
obtained after using GLY or DMF. Further studies are recommended to validate the in
vivo fertilization of these cryoprotective agents.