Factors affecting in vitro production of buffalo embryos

ABSTRACT

The present study was designed to examine the influence of oocyte quality, culture media and gonadotropins on cleavage rate and development of in vitro fertilized buffalo Oocytes. Three experiments were conducted. In Experiment 1; oocytes were classified by number of cumulus cell layers and morphology of the oopbsm as Good, Fair or Poor. Oocytes were cultured for IVM, IVF and IVC in CRlaa medium. In Experiment 2, good quality oocytes were cultured for maturation in [1] CR1aa; [2] CR2aa; [3] TCM-199; [4] MEM and [5] RPMI-1640, and then fertilized using frozen thawed buffalo spermatozoa in CRlaa. After fertilization, oocytes were cultured in the same medium used for maturation. In Experiment 3, oocytes were classified into 3 groups Group [1] without gonadotropin and served as control; Group [2] in which IVM medium was supplemented with 10 micro g/ml FSH; Group [3] in which IVM medium was supplemented with 10 IU /ml PMSG. In all experiments, oocytes were kept at 38.5°C under 5% CO[2] for IVM, IVF, IVC and examined for cleavage and embryo development rates on day 3 and 8, respectively. Good and fair quality oocytes produced a higher [P <0.01] cleavage rate than poor quality oocytcs. Morula production rate was also higher [P < 0.01] for good as compared to fair quality oocytes. Embryo development with poor quality oocytcs was arrested at the 2 to 16-cell stage. In, Experiment 2, the cleavage rate was significantly higher [P < 0.05] in CR1aa than CR2aa. and significantly higher [P < 0.01] than TCM-199, MEM and RPMI-1640. The numbers of morulae and blastocysts were higher [P < 0.01] for oocytes cultured in CR1aa and CR2aa media than TCM-199 or MEM. In Experiment 3, the addition of FSH or PMSG to the maturation medium significantly increased [P < 0.01] cleavage and developmental rates of buffalo embryo compared to control media. In conclusion, the IVM of good quality buffalo oocytes in CR1aa or CR2aa medium and the addition of FSH or PMSG in maturation medium produced higher cleavage and developmental rates of IVF buffalo embryos