Effect of isoflavone compounds on the in vitro maturation of sheep oocytes

Phytoestrogens are oestrogen-like but non-steroidal substances that are classified according to their chemical structure: flavones, flavanones, lignans, flavonols, chalcones, isoflavones. The serious problems caused by phytoestrogens in clovers on fertility in female sheep are well documented and led to the inclusion of ‘duty of care’ in the development of novel pasture species [1]. We therefore tested whether isoflavones (genistein, biochanin-A, formononetin) affected in vitro maturation or developmental competence of ovine oocytes, using a factorial design (3 isoflavones x 5 concentrations: 0, 2.5, 5, 10, 25 µg/mL) repeated 4 times. Cumulus-oocyte-complexes from abattoir-sourced adult ovaries were randomly allocated to the treatments, then fertilized and cultured in vitro [2]. Cleavage and embryo development rates were recorded.