author(s)
Lomen W Singh, Pritviraj M Barua, Joyshikh Sonowal, Keshab C Nath, Probodh Borah, Rumi S Borah, Arunima Das, Dwipjyoti Mahanta, Rubal Das and Waseem A Malla

abstract
The present study examined the effect of epigallocatechin gallate (EGCG) during In-vitro maturation (IVM) and In-vitro fertilization (IVF) of bovine oocytes. Cumulus-oocyte complexes (COCs) were aspirated from the ovaries derived from slaughter house and cultured in Tissue culture medium-199 supplemented with 5, 10 or 15 µM of epigallocatechin gallate for 24 h. Oocytes of a control group were matured in a maturation medium without EGCG. After IVM, COCs were coincubated with frozen-thawed spermatozoa for 15–18 h. In comparison with the absence of EGCG, treatment with EGCG at 10 and 15 µM showed a significant increase in the proportion of cumulus cell expansion, 1st polar body and 2^nd polar body. However, compared to control, the presence of 10 and 15 µM EGCG during IVM significantly (P < 0.01) increased the proportion of In-vitro maturation and fertilization rate. However, a further decrease to 5 µM EGCG reduced (P < 0.01) the In-vitro maturation and fertilization rate. The results suggest that at certain concentrations of EGCG (10 and 15 µM) in IVM medium has beneficial effects on In-vitro maturation and subsequent In-vitro fertilization of bovine oocytes.