MORPHOLOGICAL AND HISTOLOGICAL CLASSIFICATIONS OF BUFFALO OVARIAN FOLLICLES AND THE ABILITY OF THEIR E NCLOSING OOCYTES TO MATURE AND DEVELOPE IN VITRO.

The developmental competence of buffalo oocytes in vitro is much lower than that of cattle. This could be due to factors related to the quality of the oocytes. Two experiments were conducted to evaluate (1) the relationship between macroscopic, microscopic characteristics of buffalo ovarian follicles and the quality of cumulus-oocytes complexes (COCs), and (2) to study the ability COCs retrieved from these follicles to mature and develop in vitro to the blastocyst stage. In Experiment 1: follicles (3 to 8 mm in diameter) Were dissected from buffalo ovaries and Classified according to their macroscopic Appearance into 3 groups; clear vesicular, intermediate and opaque. Under Stereomicroscope, follicles from the 3 groups were punctured using fine needle and COCs were collected and classified into 3 categories (good, fair and poor quality). Follicular wall was fixed in formol saline (10%) for histological examination and COCs were fixed in 2.5% glutaraldehyde and processed for semi- thin section to evaluate the oocyte quality In experiment 2, good and fair quality oocytes were collected as in experiment 1 and in vitro matured in TCM medium supplemented with 10% fetal calf serum (FCS) + 10 g/ml FSH + 10 IU/ml hCG + 50 pg/ml gentamycin. Maturation was performed for 24 h under 5% CO, in humidified air. After maturation, 50 oocytes from each group were fixed in 1:3 acetic:ethanol and stained with 1% orcein to evaluate the nuclear maturation (metaphase II stage). The rest of matured oocytes were fertilized using frozen-thawed buffalo