Effect of ambient temperature on in vitro fertilization of Bubaline oocyte.

The present study was used to examine the effect of ambient temperature on the day of slaughter of buffaloes on oocyte cleavage and subsequent embryo development following in vitro fertilization (IVF)/chemical activation (parthenogenesis). A total of 601 oocytes were collected from buffaloes, which were sacrificed when the ambient temperature was >40 or < or =40 degrees C and the collected oocytes were matured in vitro. During each experiment about half of the matured oocytes were used for IVF whereas the remaining oocytes were subjected to one of the three chemical activation protocols viz. (i) 7% ethanol (ET) and 6-di methyl amino purine (6-DMAP), (ii) ET and cycloheximide (CHX) and (iii) ET followed by a combined treatment of 6-DMAP and CHX. Cleaved oocytes were cultured in mSOF supplemented with BSA, essential amino acids, non-essential amino acids, ITS (insulin transferrin and selenium) and L-glutamine. Low cleavage and subsequent embryo development was observed in those oocytes which were collected from buffaloes slaughtered at ambient temperature >40 degrees C than at < or =40 degrees C. There was no significant difference in cleavage rate following different chemical activations in oocytes collected from buffaloes slaughtered on the day when the maximum ambient temperature was >40 degrees C or < or =40 degrees C. These results suggest that high ambient temperature influences competence of oocytes to cleave and develop to blastocyst stage following natural activation with sperm and/or process of fertilization and subsequent embryo development.