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% CO(2) 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.