Caffeine supplementation during IVM improves frequencies of nuclear maturation and preimplantation development of dromedary camel oocytes following IVF.

Caffeine supplementation during oocyte IVM has been reported to improve preimplantation embryo development and the quality of in vitro-produced blastocysts in a range of species; but no studies have been done in camels. The present study investigated the effect of caffeine supplementation during dromedary camel oocyte IVM on nuclear maturation rates, IVF events, and subsequent preimplantation development. Cumulus-oocyte complexes obtained at slaughter were matured in vitro in caffeine supplemented medium either for 30 hours (caffeine 30 hours) or in the medium without caffeine supplement for 24 hours and then transferred to freshly prepared IVM medium supplemented with 10 mM caffeine for another 6 hours (caffeine 6 hours). Cumulus-oocyte complexes matured for 30 hours in the medium without caffeine supplement were used as a control. Matured oocytes were fertilized in vitro by epididymal spermatozoa of mature male camels collected from a local slaughterhouse. Eighteen hours after insemination, presumptive zygotes were cultured in modified KSOMaa medium for 7 days. Maturation and fertilization rates were significantly higher in the caffeine 6-hour group compared with the control group (P < 0.05), whereas IVM of oocytes in caffeine-supplemented medium for 30 hours did not affect these parameters (P > 0.05). Interestingly, IVM of oocytes in caffeine supplemented medium for 6 hours significantly (P < 0.05) increased the frequencies of blastocyst development by more than two-fold when compared with control (27.78% vs. 11.76%). In conclusion, culturing dromedary camel oocytes in maturation medium without caffeine for 24 hours and then in the medium supplemented with 10 mM caffeine for 6 hours during 30-hour IVM can significantly improve frequencies of nuclear maturation, fertilization rate, and subsequent preimplantation development.