Selection of Developmentally Competent Oocytes Using Brilliant Cresyl Blue Stain to Promote Blastocyst Development Rate After Somatic Cell Nuclear Transfer in Goat

摘要

The objective of the present study was to evaluate the usefulness of brilliant cresyl blue (BCB) test in the selection of more competent goat oocytes for somatic cell nuclear transfer (SCNT) experiments. BCB test determines the activity of glucose-6-phosphate dehydrogenase (G6PDH); the activity of this enzyme is highest in growing oocytes, but it declines as oocytes mature. Cumulus oocyte complexes (COCs) obtained from slaughterhouse goat ovaries were randomly divided into control group, which were immediately subjected to in vitro maturation (IVM) without BCB exposure and treatment group, which were subjected to BCB staining for 90 min before IVM. Among the treatment group, the COCs which showed blue coloured cytoplasm (low G6PDH activity) were designated as BCB+ and the COCs which showed colourless cytoplasm (high G6PDH activity) as BCB-. Then the in vitro matured oocytes were subjected to nuclear transfer by handmade cloning (HMC) method. Cleavage and blastocyst development rate was recorded onDay 2 and Day 7 post SCNT respectively. BCB+ oocytes yielded a significantly (p<0.05) increased cleavage rate (81.22%) as well as blastocyst production rate (35.21%) than the corresponding values of control (68.67% and 18.67% respectively) and BCB- group(45.26% and 5.11% respectively). In conclusion, BCB test can be used very successfully for the selection of developmentally competent goat oocytes which can yield increased blastocyst production after nuclear transfer.