NAD, Sirtuins and PARPs: enhancing oocyte developmental competence.

Oocyte quality is the limiting factor in female fertility. It is well known that maternal nutrition plays a role in reproductive function, and manipulating nutrition to improve fertility in livestock has been common practice in the past, particularly with respect to negative energy balance in cattle. A deficiency in nicotinamide adenine dinucleotide (NAD) production has been associated with increased incidences of miscarriage and congenital defects in humans and mice, while elevating NAD through dietary supplements in aged subjects improved oocyte quality and embryo development. NAD is consumed by Sirtuins and poly-ADP-ribose polymerases (PARPs) within the cell and thus need constant replenishment in order to maintain various cellular functions. Sirtuins and PARPs play important roles in oocyte maturation and embryo development, and their activation may prove beneficial to in vitro embryo production and livestock breeding programs. This review examines the roles of NAD, Sirtuins and PARPs in aspects of fertility, providing insights into the potential use of NAD-elevating treatments in livestock breeding and embryo production programs.