Effectiveness of Menuzo's B2 medium with buffalo rat liver cells for development of in vitro matured/in vitro fertilized bovine oocytes

Purpose: The effectiveness of two culture media on the development of bovine embryos in a buffalo rat liver (BRL) coculture system was investigated. Methods: Bovine oocytes were matured and fertilized in vitro, then cocultured, 25 per well, for 7 days in 500 μl of modified M199 or modified Menuzo's B2 medium over a BRL cell monolayer at 39°C in an atmosphere of 5% CO~2 in air. Medium 199 was modified by the addition of 10% of (v/v) fetal bovine serum (FBS), 9 mg/ml bovine serum albumin, 2 mM glycine, 1 mM alanine, and 0.1 mM nonessential amino acids (NEAA). Menuzo's B2 medium was modified by the addition of 10% (v/v) FBS, 1 mM alanine, and 0.1 mM NEAA. Results: Modified Menuzo's B2 medium improved embryo development to the morula or blastocyst stage compared to modified M199 (121/353, 34.3%, versus 99/362, 27.3%, P < 0.05). Conclusions: These results suggest that Menuzo's B2 medium with modifications in a BRL coculture system can provide a significant benefit for culture of early bovine embryos over the traditional use of medium 199.