Banca de DEFESA: Natalia Ernandes Capobianco

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Natalia Ernandes Capobianco
DATE: 31/08/2022
TIME: 08:00
LOCAL: Videoconferência
TITLE:

"Assessment of seminal cell-free DNA as a potential marker for bovine sperm quality and freezability"

KEY WORDS:

cfDNA; freezability; seminal plasma, in vitro embryo production

PAGES: 73
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Sperm cryopreservation is a great impact technique used in animal production. Although it is well established in some species, the response to cryopreservation is varies depending on individual. Thus, the identification of a marker that can indicate the freezeability and fecundity of the sample, prior to freezing, would be of great value to the semen industry. Them, searching for a new assessment that can predict post-thawing sperm quality, this study evaluated the amount of cellfree DNA and mtDNA copy number in the seminal plasma of Nellore bulls. Semen from nine bulls was collected by electroejaculation, half of the ejaculate was used to fresh semen evaluation and obtain seminal plasma for cfDNA quantification, the other half was cryopreserved. Evaluation of sperm movement by CASA (IVOS 12.3/Hamilton-Thorne, USA) and of plasma membrane integrity and stability, acrosomal integrity, apoptosis, and mitochondrial potential by flow cytometry (AMNIS FlowSight - Amnis Corp., USA) were performed on fresh semen and frozen/thawed semen at 0, 3, 6 and 12h after thawing. Cryopreserved semen was also used for in vitro embryo production. Quantification of cfDNA was performed by spectrophotometry and the mtDNA copy number was quantified by qPCR. The concentration of cfDNA present in seminal plasma ranged from 15.23 ng/μL to 519.71 ng/μL. The median was calculated (58.95) and two groups were defined according to cfDNA concentration: LowcfDNA (<58.95 ng/μL; n=5) and HighcfDNA (>58.95 ng/μL; n=4). The mtDNA copy number was similar (P>0.05) between groups. In fresh semen, the percentage of cells with membrane stability was higher (P<0.05) in the LowcfDNA group (84.24%) compared to the HighcfDNA group (52.72%) and, over 12 hours post-thawing, there were no differences for all parameters evaluated between groups. Cleavage and D7 blastocyst rates were higher for the HighcfDNA group (60.74% ± 3.38 and 24.95% ± 2.56, respectively) than for the LowcfDNA group (41.21% ± 3.23 and 6.42 ± 1.14). The HighcfDNA group also produced better quality embryos. The concentration of cfDNA in seminal plasma is not able to predict the freezeability of semen, but animals with a greater amount of cfDNA are able to produce more embryos and of better quality in vitro.

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