
%0 Journal Article
%A Kim, K. S. 
%A Minami, N. 
%A Yamada, M. 
%A Utsumi, K. 
%T Follicular cells affect the fertilizability and developmental competency of bovine oocytes <emph type="2">in vitro</emph>
%J Reproduction, Fertility and Development
%D 1998/06/30
%V 9
%N 8
%P 763-766
%K 
%R https://doi.org/10.1071/R97009
%U https://www.publish.csiro.au/paper/R97009 
%X The present study examined the time-dependent effects of follicular cells on the fertilizability of oocytes and their subsequent development to blastocysts. The percentages of oocytes reaching the metaphase-II stage of maturation rose from 51&#183;3% after 16 h of culture to 86&#183;2% at 28 h (cumulus-intact oocytes; CIO) and, for the same time points, from 65&#183;4% to 83&#183;3% (corona-enclosed oocytes; CO) and 54&#183;3% to 88&#183;9% (denuded oocytes; DO), respectively. When DO were cultured for more than 24 h before insemination, fertilization rates were significantly lower compared with CIO and CO. The maximum rates of development to blastocysts were observed when the oocytes were cultured for 24 h in the CIO group (22&#183;1%), 20 h in the CO group (19&#183; 7%) and 18 h in the DO group (9&#183;2%), respectively. These results suggest that (i) the presence of cumulus cells or corona cells during maturation is not necessary for nuclear maturation of oocytes; (ii) the attachment of corona cells to the oocytes during maturation is important for the further development to the blastocyst stage, and (iii) the presence of attached cumulus and/or corona cells during maturation in vitro extends the maturation period required for further development to the blastocyst stage. 
