DEVELOPMENT OF BOVINE EMBRYOS IN SINGLE IN-VITRO PRODUCTION (SIVP) SYSTEMS

Single in vitro production (sIVP) of embryos enables the study of deve lopmental parameters of individual oocytes or embryos. Because several previously published sIVP systems showed varying levels of success, w e attempted to design a simple, semidefined sIVP system that resulted in developmental rates similar to those obtained through group product ion (gIVP). In a 5 x 3 x 4 factorial experiment, 4200 oocytes were ran domly assigned to combinations of various maturation (sIVM), fertiliza tion (s:VF), and culture (sIVC) treatments based on media TCM199 (5 tr eatments), TALP (3 treatments), and SOF/aa/BSA (4 treatments), respect ively. All sIVP steps were carried out in 10-12 mu 1 drops under oil. Embryo development to blastocyst on days 7 and 8 of culture was determ ined and blastocyst cell numbers measured as an indicator of embryo qu ality. No interaction was found within any combination of sIVM, sIVF a nd sIVC treatments. Also, there was no difference in percentage of dev elopment to various stages for embryos in any of the sIVM or slVF trea tments (over all treatment combinations), However, when treatment comb inations included charcoal-treated serum addition on day 5 of culture, a significant increase in development (39.0% total blastocysts/total oocytes vs. 22.7, 23.8 and 23.5% for the other 3 sIVC treatments, resp ectively; P < 0.001) and decrease in mean cell number (114.2 vs. 149.1 ., 150.5 and 143.7 cells, respectively; P < 0.001) was ob served, Thes e results are comparable to those routinely obtained in this laborator y with gIVP and establish standard conditions for individual embryo pr oduction. (C) 1998 Wiley-Liss, Inc.