Dietary antioxidant supplementation did not affect declining sperm function with age in the mouse but did increase head abnormalities and reduced sperm production.

The present study aims to ascertain whether dietary administration of a mixture of vitamins C and E may prevent the negative effects of paternal age on male fertility variables in the mouse. Experimental males were fed a standard diet supplemented with either a low or high dose of vitamins C and E. Oocytes enclosed in cumulus masses were inseminated using a 2 x 2 factorial design established according to whether males were young (3-4 months of age) or aged (22-24 months of age) and whether they were fed a control or antioxidant diet. Aged males showed a significant decrease in number of spermatozoa/mg epididymis when compared to young males. Dietary supplementation with low doses of vitamins C and E did not have any effect on sperm quality, fertilization and conceptus development in vitro. However, high doses of dietary vitamins C and E decreased the number of spermatozoa/mg epididymis, and increased the percentage of spermatozoa with misshapen heads distended in the distal part. These findings suggest that dietary supplementation with pharmacological doses of vitamins C and E may disturb spermatogenesis. The mechanism involved may be associated with either the antioxidant properties of vitamins C and E or their inhibitory action on steroidogenesis by Leydig and/or Sertoli cells.