| Early embryo development is crucial for mammalian reproduction and forms the basis of assisted reproductive technologies (ART). An integral yet seemingly inefficient component of ART is in vitro embryo production (IVP). Current IVP media is devoid of thyroid hormones (THs), which we believe are necessary for normal embryo development. Follicular fluid aspirates and serum samples from post mortem and live synchronized cows contained THs at levels comparable to those in serum. TH supplementation of IVP media enhanced early embryo development. Embryo competency was significantly enhanced as evidenced by increased blastocyst formation and hatching rates. Embryo quality was significantly improved as demonstrated by greater total cell counts and reduced apoptotic rates. Finally, improved post-cryopreservation viability was associated to TH supplementation. These findings not only provide a way of optimizing assisted reproductive technology efficiency, but also further our understanding of the roles of THs in reproductive biology. |
