Technical Report: Effect of commercially available PMSG on maturation, fertilization and embryo development of buffalo oocytes in vitro

Abstract

In vitro fertilization (IVF) technology provides an opportunity to produce embryos for genetic manipulation, embryo transfer and basic research in developmental physiology, and can be exploited for emerging biotechnologies such as transgenesis and cloning. In the present study, the effects of different concentrations of commercially available pregnant mare serum gonadotrophin (PMSG) (Folligon; Intervet, International B.V., Boxmeer, Holland) in oocyte culture media, on maturation, fertilization and embryonic development of buffalo oocytes in vitro were investigated. Oocytes aspirated from abattoir-derived ovaries were cultured in media containing TCM-199 + PMSG at 0, 2.5, 20, 30, 40 and 50 IU mL^–1 in presence or absence of steer serum (10%) for 24 h in a CO₂ incubator. The maturation rate was assessed on the basis of degree of expansion of cumulus cells. The matured oocytes were inseminated with 9–10 x 10⁶ spermatozoa mL^–1 in Brackett and Oliphant medium and the cleavage rate was recorded 40–42 h after insemination. Uncleaved oocytes were stained with aceto-orcein for evaluation of fertilization rates. The cleaved embryos were further cultured in TCM-199 + 10% steer serum on buffalo oviducal cell monolayer for 7 days. Maturation, fertilization, cleavage and embryonic development were significantly higher (P<0.05) in oocytes cultured in TCM-199 + 10% steer serum supplemented with 40 and 50 IU PMSG mL^–1. It is concluded that commercially available PMSG can effectively be used in place of pure follicle-stimulating hormone for in vitro maturation of buffalo oocytes, making it cost effective for IVF studies.