DOES THE FOLLICULAR FLUID OBTAINED FROM BOVINE FOLLICLES OF DIFFERENT DIAMETERS INFLUENCE OOCYTE DEVELOPMENT?

The effect of follicular fluid (FF) of small (SFF= 8mm) and large (LFF= >8mm) follicles in the maturation medium on bovine oocyte maturation, fertilization and subsequent development was evaluated. Oocytes were randomly assigned into 5 groups. The oocytes of Estrous Mares Serum (EMS) group were treated with 10% of EMS. In the remaining four groups 20% of bovine FF was added. These groups received FF from different follicle diameter. In the group EMS (n=147) oocytes were maintained for 24h in 10% EMS; Group SFF (n=149) for 24h in SFF; Group LFF (n=147) for 24h in LFF; Group SFF+LFF (n=149) for 12h in SFF plus 12h in LFF; Group LFF+EMS (n=144) for 12h in LFF plus 12h in EMS. Fertilization was performed by incubation of sperma and oocytes in FERT-TALP medium for 18h. Zygotes were cultured in medium Synthetic Oviduct Fluid with amino acids, sodium citrate and myo-inositol (SOFaaci). The cleavage on Day 2 (D0 = fertilization day) and hatching rates on Day 9 were similar among groups (P>0.05). However, oocytes matured in medium with LFF showed higher (P 0.05) blastocyst yield on Day 7 compared to oocytes in vitro matured in medium with SFF. The addition of follicular fluid from small and large follicles to the maturation media supports in vitro maturation and embryonic development. Key words: oocytes, maturation, follicular fluid, embryo.  O FLUÍDO FOLICULAR OBTIDO DE FO