Different roles for B-carotene and vitamin A in the reproduction on rabbits

beta-carotene is thought to have a positive effect on reproduction independent of its role as a vitamin A precursor. The effect of beta-carotene related to vitamin A in rabbit fertility was examined in 2 independent experiments. All rabbits received sufficient dietary vitamin A. The first experiment (superovulation and embryo transfer) was designed to determine possible effects of beta-carotene sources (synthetic and natural) on embryo donors and recipients. In the second experiment (superovulation) the influence of beta-carotene (synthetic) on vitamin A status in the blood and on reproductive performance was studied. There was no obvious effect of beta-carotene on the numerous traits measured. High levels of serum vitamin A in Experiment 2, however, were positively related to an improvement in reproduction (higher numbers of corpora lutea, lower numbers of cysts, more oocytes, more embryos, more embryos suitable for injection). These data suggest that the previously described effects of beta-carotene are mainly based on the metabolism of vitamin A.