ABSTRACT
Conventional culture conditions for the preimplantation mammalian embryo induce a considerable amount of cellular stress within the blastomeres of the embryo. Manifestations of such stress are retarded rates of cleavage, cleavage arrest, cytoplasmic blebbing, abnormal genome activation and gene transcription, and abnormal patterns of energy metabolism. All of these manifestations of culture-induced stress culminate in a loss of viability. It is therefore paramount that culture media minimize such stress within the embryo and facilitate normal cell function, and hence maintain embryo viability1-3. One of the cellular processes affected by suboptimal culture conditions, energy metabolism, has been shown to be a useful marker of embryo normalcy in vitro. Furthermore, energy metabolism may also be used to identify the most viable embryo from within a given cohort for transfer. It is therefore the aim of this chapter not only to review the nutrient requirements and energy metabolism of the mammalian preimplantation embryo, but also to put energy metabolism into a meaningful context with regard to embryo development, culture and viability assessment.
