Effect of alpha-tocopherol on bovine in vitro fertilization.
The objectives of this work are to determine if exogenous supplementation with alpha-tocopherol increases the in vitro fertilization (IVF) rate of bovine oocytes and improves viability of selected spermatozoa after 'swim-up'. The percentage of fertilized oocytes was significantly but negatively correlated (r = -0.941, p < 0.01) with the concentration of alpha-tocopherol. The control resulted in 95% of fertilized oocytes, which decreased as follows: 25 microM alpha-tocopherol (alpha25) 86%, 50 microM alpha-tocopherol (alpha50) 74%, 100 microM alpha-tocopherol (alpha100) 66% and 200 microM alpha-tocopherol (alpha200) 56%. Relatively to sperm viability after 'swim-up' with alpha-tocopherol supplementation, this antioxidant proved to have a beneficial effect as its concentration increased up to alpha50, decreasing for the concentrations of alpha100 and alpha200. Control resulted in 83% of live cells and 16% of dead cells; alpha25 resulted in 88% of live cells and 12% of dead cells; alpha50 resulted in 91% of live cells and 9% of dead cells; alpha100 resulted in 67% of live cells and 33% of dead cells; and finally alpha200 resulted in 57% of live cells and 42% of dead cells. In summary, the present study allows to conclude that, in our conditions, supplementation with the antioxidant alpha-tocopherol in IVF of bovine oocytes has a detrimental effect on fertilization rates. Nevertheless, exogenous supplementation with alpha-tocopherol at a concentration of 50 mM in the sperm-TALP media during the 'swim-up' technique has a significant beneficial effect on the selected spermatozoa viability.
Marques
A
A
Department of Agrarian Science, University of the Azores, Angra do Heroísmo, Portugal. andreiamarques@uac.pt
Santos
P
P
Antunes
G
G
Chaveiro
A
A
Moreira da Silva
F
F
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D046149:Embryo Culture Techniques / Q000662:veterinary; D005260:Female; D005307:Fertilization in Vitro / Q000187:drug effects / Q000662:veterinary*; D006107:Granulosa Cells / Q000502:physiology; D008297:Male; D009865:Oocytes / Q000254:growth & development; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology; D024502:alpha-Tocopherol / Q000494:pharmacology*
D000975:Antioxidants; D024502:alpha-Tocopherol