THE EFFECT OF CULTURE MEDIA AND CULTURE TIME ON THE IN VITRO MATURATION OF DOMESTIC CAT OOCYTES

Abstract

Culture media and culture time play important roles in meiotic competence and in vitro development of domestic cats oocytes. This experiment was designed to investigate the effects of culture media (M199 versus DMEM) on the in vitro maturation of domestic cat oocytes, after culturing for 24, 36 and 48 h. Domestic cat ovaries were obtained from routine ovariohysterectomy at an animal hospital, cooled to 4oC and transferred immediately to the laboratory. The oocytes were collected by slicing ovaries in the collecting medium. Five to ten cumulus oocyte complexes (COCs) were cultured in small drops of 50 μl of M199 or DMEM for 24, 36 and 48 h, under light mineral oil, at 38.5oC and 5% CO2, in a humidified atmosphere. The meiotic status of the cultured oocytes was assessed according to their chromosomal development and meiotic competence, after staining with basic fuschin and acetoglycerol and observation under a light microscope. The results showed that the maturation rate of domestic cat oocytes cultured in M199 was not significantly different (P>0.05) from those cultured in DMEM for 24, 36 and 48 h. However, the oocytes cultured in either M199 or DMEM for 36 h gave the best maturation rate (48.0% (49/102) and 48.1% (50/104) respectively), although not significantly different (P>0.05) when compared to other culture times. The results suggest that domestic cat oocytes can be matured in vitro in either M199 or DMEM and that 36 h is the appropiate time for culture rather than 24 and 48 h.