The present study aimed to investigate the effect of ovarian antral follicle type (AF) on oocyte quality and oocyte maturation in vitro (IVM) and its relationship to some components of follicular fluid in buffaloes. Buffalo ovaries were collected from slaughterhouse. Ovarian follicles were classified into two types. Type (1) antral follicles of ≥3mm in diameter (AF) and type (2) small antral follicles of < 3mm in diameter (small AF). Oocytes were aspirated from each type of follicles then it were classified into good oocytes embedded within compact cumulus cells and having granulating ooplasm and fair oocytes showing only a few layers of cumulus cells and poor oocytes (denuded oocytes and those with a pyknotic ooplasm). Oocytes were matured in a defined basic maturation medium (TCM 199). The results indicated that, the percentage of good quality oocytes was higher with oocytes which aspirated from type 1 (61.68%) than those aspirated from type 2 (28.32%).
The percentages of fair and poor quality oocytes were higher in type 2 (33.63 % and 38.05 %) than those with type 1 (26.51% and11.81 %), respectively and the differences were significant (P≤0.001). The percentage of oocyte maturation (reaching metaphase II (M II) within 21-24 h culturing time was higher with oocytes obtained from type 1 (75.00%) than those (42.48%) that were obtained from type 2 and differences were significant (P≤0.001).Chemical analysis of some follicular fluid components (Glutathione, malondialdehyde (MDA), zinc and Selenium) were 4.5 mmol/L, 1.76 mmol/L, 0.27 mg/dl and 5.35 mg/dl in follicular fluid of AF and 1.52 mmol/L, 3.89 mmol/L, 0.16 mg/dl and 2.78 mg/dl in follicular fluid of small AF, respectively and the differences were significant(p≤ 0.05). In conclusion, AF has an important role in oocyte quality and oocyte maturation rate. Besides high concentration of follicular fluid of glutathione, zinc and selenium was related to AF and high concentration of follicular fluid MDA was related to small AF