EFFECT OF ALPHA-TOCOPHEROL AND ASCORBIC-ACID ON BOVINE IN-VITRO FERTILIZATION

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.