Effects of amino acids on the development of in-vitro matured in-vitro fertilization bovine embryos in a simple protein-free medium

The effects of commercially available amino acids, referred to as Eagle's non-essential amino acids (NEAA) and essential amino acids (EAA), on the development of bovine embryos produced by in-vitro maturation and in-vitro fertilization (IVF) in a simple modified protein-free KSOM medium containing polyvinyl alcohol (PVA) were studied, Embryos produced by IVF were cultured in an atmosphere of 5% O-2, 5% CO2 and 90% N-2 at 39 degrees C for the first 40-44 h in modified KSOM, Then embryos with four or more cells were cultured in modified KSOM-PVA with different amino acids for another 6 days in experiments 1 and 2, In experiment 3, to study embryo hatching and degeneration further as criteria of medium suitability, the culture time was 8 days, In experiment 1, more blastocysts were produced (P < 0.05) in the medium with 0.5X NEAA (37%) than with 0.25 or 0.5X EAA (both 15%), In experiment 2, when 0.0, 0.5 and 1.0X concentrations of NEAA were combined with 0.0 and 0.5X concentrations of EAA, the combination 1.0x NEAA with 0.5X EAA resulted in the most blastocysts (39%), with 11% hatching (P < 0.05), Without NEAA, 1.0X EAA resulted in 6% blastocysts (P < 0.05), In experiment 3, KSOM-PVA with 1.0X NEAA plus 0.5X EAA resulted in 41% blastocysts, similar to the 40% blastocysts in KSOM-bovine serum albumin (BSA) with the same amino acids added, When culture was continued for 2 more days, more embryos hatched in these two treatments, These results indicate that the combination of 1.0X NEAA with 0.5X EAA promoted blastocyst formation and hatching, but EAA alone was detrimental, With PVA successfully replacing BSA, a completely defined medium resulted, which was equal or superior to complex medium, and is potentially useful for the culture of embryos from other species, such as humans.