The aim of this work was to study the effect of alpha-tocopherol (vita
min E) and ascorbic acid on the in vitro fertilization process. Frozen
bovine semen was prepared using extenders with and without addition o
f vitamin E. Samples were capacitated with heparin in the fertilizatio
n medium. In vitro matured oocytes were inseminated with spermatozoa f
rozen with and without vitamin E and, after thawing, fertilized in TAL
P medium (control) and in TALP medium with vitamin E (1 mg/ml), with a
scorbic acid (5 mM) and with vitamin E plus ascorbic acid. Gametes wer
e incubated in the respective fertilization medium for 48 h; those fro
zen without vitamin E yielded 75, 76, 69 and 49% of fertilized oocytes
in the control, vitamin E, ascorbic acid and vitamin E plus ascorbic
acid media, respectively. The last value was, significantly different
(P < 0.01). In bovine sperm frozen with vitamin E, fertilization rates
were 74, 50, 47 and 34%, respectively for the 4 groups. Values observ
ed for the different supplements were significantly different inter se
(P < 0.01), except between the media with vitamin E and with ascorbic
acid. These results indicate that preserved antiooxidant capacity of
vitamin E impairs the success of the in vitro fertilization process. (
C) 1998 by Elsevier Science Inc.