Abstract
This study was carried out to investigate the nuclear maturation and embryo development after in vitro fertilization of sheep cumulus oocyte complexes (COCs), either in green tea leaves extract (GTE) supplemented tissue culture medium (TCM-199) at different concentrations (0, 0.3, 0.6 and 1.2 mg ml(-1)). Oocytes of a control group were matured in a maturation medium without GTE (0 mg GTE ml(-1)). After maturation, half of oocytes were fixed and stained to evaluate the nuclear maturation. The rest of oocytes were fertilized in vitro with fresh semen then cultured for 9 days for assessment of the oocytes developmental capacity. The results showed that supplementation of GTE resulted in a significantly (p <= 0.05) increasing of oocytes developed to metaphase II (M II) when compared to control group, exception group V that no significant difference compared to group I. Group II showed higher significant M II than other treatments groups. Addition of GTE to IVM medium resulted in significantly improvement of blastocyst formation with 0.3 mg ml(-1) concentration than 0.6, 1.2 mg ml(-1), and control group. It was concluded that GTE at concentrations of 0.3 mg ml(-1) IVM medium improvement the in vitro maturation and embryo development of sheep COC's to blastocyst stage. Also, addition of GTE at 0.6 mg ml(-1) to IVM medium had little benefit in increasing the maturation rate and blastocyst formation.