In Vitro Fertilization of In Vitro-Matured Equine Oocytes: Effect of Maturation Medium, Duration of Maturation, and Sperm Calcium Ionophore Treatment, and Comparison with Rates of Fertilization In Vivo after Oviductal Transfer1

Abstract

Three experiments were conducted to evaluate the effect of oocyte and sperm treatments on rates of in vitro fertilization (IVF) in the horse and to determine the capacity of in vitro-matured horse oocytes to be fertilized in vivo. There was no effect of duration of oocyte maturation (24 vs. 42 h) or calcium ionophore concentration during sperm capacitation (3 microM vs. 7.14 microM) on in vitro fertilization rates. Oocytes matured in 100% follicular fluid had significantly higher fertilization (13% to 24%) than did oocytes matured in maturation medium or in 20% follicular fluid (0% to 12%; P < 0.05). There was no significant difference in fertilization rate among 3 sperm treatments utilizing 7.14 microM calcium ionophore (12% to 21%). Of in vitro-matured oocytes recovered 40-44 h after transfer to the oviducts of inseminated mares, 77% showed normal fertilization (2 pronuclei to normal cleavage). Cleavage to 2 or more cells was seen in 22% of oocytes matured in follicular fluid and 63% of oocytes matured in maturation medium; this difference was significant (P < 0.05). We conclude that in vitro-matured horse oocytes are capable of being fertilized at high rates in the appropriate environment and that in vitro maturation of oocytes in follicular fluid increases fertilization rate in vitro but reduces embryo development after fertilization in vivo. Further work is needed to determine the optimum environment for sperm capacitation and IVF in the horse.

Deleted in malignant brain tumor 1 is secreted in the oviduct and involved in the mechanism of fertilization in equine and porcine species

“…This result is interesting, considering that conventional IVF has only limited success in equine species (Palmer et al 1991, Dell'aquila et al 1996, Hinrichs et al 2002, McPartlin et al 2009, Mugnier et al 2009). We chose the technique developed by McPartlin et al (2009) in which spermatozoa were hyperactivated using procaine.…”

“…The exposure of oocytes to porcine oviductal epithelial cells or oviductal fluid before IVF improves the rate of monospermy (Romar et al 2001. In equine species, IVF rates are low and no repeatable IVF technique is available yet (Palmer et al 1991, Dell'aquila et al 1996, Alm et al 2001, Hinrichs et al 2002, McPartlin et al 2009). We have shown a beneficial effect of homologous and heterologous oviduct cells on equine IVF rates (Mugnier et al 2009).…”

Establishment of conditions for ovum pick up and IVM of jennies oocytes toward the setting up of efficient IVF and in vitro embryos culture procedures in donkey (Equus asinus)

“…The third step is IVF of oocytes. Several attempts to establish an efficient conventional IVF technique in the equine have been performed, but IVF rates remained quite low and IVF techniques were not repeatable [24][25][26][27][28][29][30]. Intracytoplasmic Sperm Injection (ICSI) has been widely adopted to generate horse embryos in vitro, both for scientific purposes and in the horse breeding industry [11,31].…”

Hyperactivated Sperm Motility: Are Equine Sperm Different?

“…Although some groups have reported modest rates of fertilization [1][2][3][4][5], these methods have not been repeatable. Failure of equine IVF is related to the failure of equine sperm to penetrate the zona pellucida in vitro: when the zona is breached by partial zona dissection or dissolution, it results in high fertilization rates and even polyspermy [6,7].…”