The effect of various concentrations of myo-inositol in culture medium on development of bovine embryos

BACKGROUND Progress achieved in culture media formulations have resulted led to an improvement in maintaining the mammalian embryo in culture throughout the preimplantation and pre-attachment period. OBJECTIVE The objective of this study was to evaluate the effect of various concentrations of myo-inositol during in vitro fertilization of bovine oocytes on subsequent embryo development. MATERIALS AND METHODS Bovine cumulus oocytes complexes (COCs) were matured in vitro at 39(o)C, in humidified 5% CO2 atmosphere for 22-24 h. The COCs were co-incubated with epididymal spermatozoa of post mortem bulls in modified TALP medium for 22-24hr. The fertilization medium used was: 1) TALP medium without myo-inositol (control); 2) control+0.02 g/l myo-inositol; 3) control+0.03 g/l myo-inositol; 4) control+0.04 g/l myo-inositol. Zygotes were cultured in vitro for 8 days when the ratios of in vitro embryo development of the hatched blastocysts were assessed and compared with the control group (p<0.05). RESULTS The presence of 0.04 g/l myo-inpsitol significantly improved overall morula and blastocyst rates (46.94%) compared to control (32.19%), but there was no difference in the percentage of embryos successfully developed to the morula and blastocyst stage when different levels of myo-inositol were used (46.94, 36.36 and 37.33% respectively). The mean percentage of cleavage rate was not significantly affected by treatments. CONCLUSION These results suggest that, addition of 0.04 g/l myo-inositol in TALP medium is more beneficial for subsequent bovine embryonic development.