Cumulus cells protect the oocyte against saturated free fatty acids

In the cow a major characteristic of metabolic
stress is an elevated level of plasma free fatty acid, due
to increased lipid mobilization from adipose tissue.
Elevated levels of free fatty acids in blood (complexed
to albumin) are associated with increased lipotoxicity in
non-adipose tissue. An overview is provided on the
negative impact of free fatty acids and the metabolic
stress imposed on the oocyte and early embryo and thus
on bovine fertility. There is increasing evidence that in
vitro as well as in vivo the elevated levels of free fatty
acids in blood during metabolic stress can severely
hamper oocyte and embryo development. However,
fatty acids do also form an essential nutrient source for
the oocyte and embryo, which indicates that these good
and bad effects of fatty acids should be in subtle balance
to optimize the developmental competence of the oocyte
and embryo.