Chronological changes of buffalo follicular oocytes maturation in vitro
Singh, R.; Majumdar, A.C.
Indian Journal of Animal Sciences 62(3): 205-209
The study was designed to establish a chronology of meiotic events occuring during buffalo oocyte maturation in vitro. From a local slaughterhouse, 918 ovaries were brought and 783 good quality cumulus-oocyte complexes were recovered by aspirating 2-6 mm follicles. Of these oocystes 424 were cultured in a modified TC-199 media supplemented with 20% oestrous buffalo serum for 0, 6, 12, 18, 20, 22, 24, 26, and 30 hr at 39.degree. C and 5% CO2. At the time of collection (0 hr) 62% of the oocytes were at GV stage. The rest had already resumed meiosis; presumably they were from atretic/preovulatory follicles. GVBD occurred at 6 hr and diakinesis at 6-12 hr. Metaphase I was predominant at 12-20 hr and at 22 hr 65% of the oocytes were at anatelophase-I. Metaphase-II was first observed after 18 hr of culture. Peak of maturation occurred at 24 hr when 64% of the oocytes were at metaphase-II. No substantial change in this percentage was noticed either at 26 or 30 hr, indicating that buffalo oocytes mature after 24 hr in culture.