Influence of beta-carotene on fertility in rabbits when using embryo transfer programs

The effect of beta-carotene on reproduction traits in rabbits was studied in 509 (superovulated and normally ovulated) donors and 239 recipients by using embryo/gene transfer performed at 2 different locations. All of the bucks and the half of the females were fed a diet supplemented with 40 mg synthetic beta-carotene (Rovimix((R)))/kg feed. Embryos at the pronucleus stage were collected 19 to 21 hours after induction of ovulation with human chorionic gonadotropin (hCG); they were then microinjected into the male pronucleus and transferred to synchronized recipients. Data were obtained from the time when the donors and recipients were caged, until the pups resulting from the embryo transfers were weaned. Supplemented beta-carotene did not affect most of the 30 traits that were analyzed. However superovulated donors in Project 2 that received the beta-carotene enriched diet had a 14% lighter ovary weight (P<0.05) and less than half of the oocytes were unfertilized (P<0.05). In Project 1 (beta-carotene group) there was a greater number of pups born (36%, P<0.05) and more of these pups were born alive (53%, P<0.05).