Selection of cumulus-oocyte complex for vitrification by brilliant cresyl blue.

The influence of the method of evaluating developmentally competent oocytes on their viability after cryopreservation still needs to be better understood. The objective of this study was to determine the cleavage and embryo developmental rates after parthenogenetic activation of cumulus-oocyte complexes (COCs) selected by different concentrations of brilliant cresyl blue (BCB) and cryopreservation. In the first experiment, COCs were separated into groups and incubated for 1 h in medium containing BCB (13 μM, 16 μM, or 20 μM).

Impact of cumulative gain in expertise on the efficiency of handmade cloning in cattle.

The aim of this study was to determine the effects of the cumulative gain in expertise in carrying out handmade cloning (HMC) procedures on embryo yield and pregnancy outcome in cattle. Results from in vitro and in vivo embryo development after HMC during three periods of 7 months, separated by 3-month intervals, were compiled and designated as P1, P2 and P3. Blastocyst yield, morphological quality and stage of development, and pregnancy per embryo transfer (ET) on Day 30 of gestation were compared.

Selection of Rattus norvegicus oocytes for in vitro maturation by brilliant cresyl blue staining.

The objective of this work was to evaluate the rate of meiosis resumption and nuclear maturation of rat (Rattus norvegicus) oocytes selected for in vitro maturation (IVM) after staining of cumulus-oocyte complexes (COCs) with blue cresyl brilliant (BCB) using different protocols: exposure for 30, 60 or 90 min at 26 μM BCB (Experiment 1), and exposure for 60 min at 13, 20 or 26 μM BCB (Experiment 2). In Experiment 1, the selection of oocytes exposed to BCB for 60 min was found to be the most suitable, as meiosis resumption rates in the BCB(+) group (n = 35/61; 57.37%) were the closest to the observed in the control (not exposed) group (n = 70/90; 77.

Gene expression and developmental competence of bovine embryos produced in vitro under varying embryo density conditions.

The objective of this study was to determine the effects of oocyte/embryo density (embryo number:medium volume ratio) on developmental competence and relative transcription of developmentally important genes in in vitro-produced bovine embryos. Using standard procedures, bovine oocytes were matured, fertilized and cultured in vitro in groups of 5, 10, 20 or 30 oocytes/embryos per 100 microL medium drop (embryo number/medium volume ratios of 1:20, 1:10, 1:5 and 1:3.3, respectively).