Effects of treatment with quercetin on the quality of cryopreserved bovine semen

ABSTRACT

Background: Semen cryopreservation is one of the most common biotechnologies in the reproduction of animals ofagricultural interest, especially bulls. However, cryopreservation can be harmful to sperm cells, with susceptibility tooxidative stress being one of the causes. The addition of antioxidants such as quercetin may inhibit and/or reduce suchdamage, reducing fertility. Quercetin can increasing sperm motility and interaction capacity between spermatozoa-oocyte,to increase cellular metabolism and reduced DNA fragmentation and oxidation following thawing. Therefore, the objective of this study was to evaluate the protective effect of quercetin on the metabolism of bovine semen following thawing.Materials, Methods & Results: Three Brahman bulls in reproduction age and previously considered fit for reproductionwere used. The semen samples were collected via the electroejaculation method, and the samples were homogenized toform pooled semen from three ejaculates, which was diluted in Tris-yolk egg-glicerol diluent medium. Quercetin was addedto diluent, to final concentrations of 0, 5, 10, 15 and 20 μg.mL-1 in each group. The samples were kept frozen in strawsof 500 μL, with concentration of 40,000,000 spermatozoid / mL for 15 days and were thawed in water at 36°C for 30 s.All the tests was performed in five replicates. The cell metabolism status was evaluated by quantification of superoxideradical production with a nitroblue tetrazolium test (NBT) and scanning spectrophotometry. By spermatic evaluation, thefollowing parameters were evaluated via the computerized system of sperm analysis (CASA) total motility (TM, %),progressive motility (PM, %), velocity curved line (VCL, mm/s), velocity straight line (VSL, mm/s), velocity averagepath (VAP, mm/s), distance curved line (DCL, mm), distance straight line (DSL, mm), distance average path (DAP, mm),amplitude of lateral head displacement (ALH, mm), beat cross frequency (BCF, Hz), wobble...