ABSTRACT
   
	The aim of this work is to evaluate the use of recombinant human FSH on rabbit does superovulation, embryo and oocytes quality and its viability after a cryopreservation process.

	The first experiment aimed to evaluate the effect of superovulation treatment on fresh and frozen –thawed embryo development using 25 UI rhFSH alone or in combination with 5% or 10% rhLH. Development rate to hatching blastocyst was significantly highly for non-superovulated embryos than for rhFSH or rhFSH+10% rhLH superovulated embryos. No differences were found among superovulation groups in development rate after frozen-thawed process, with an 83.5% of embryos reaching expanded balstocyst stage. On the other hand, antiFSH antibodies were detected in order to evaluate the efficiency of rhFSH treatment on does subjected to four treatments. Ovulation rate decreased after the second treatment, while a significant increase in the antibody levels increased at the moment of the third and fourth superovulation treatments.

	The aim of the second experiment was to study the effect of different superovulation treatments on oocyte quality evaluating its ATP content. Thus, control treatment, rhFSH every 24 hours treatment (rhFSH3), porcine FSH every 24 hours treatment pFSH3) or porcine FSH every 12 hours treatment (pFSH5) were performed. ATP level was significantly lower than others groups (5.63 ± 0.14 for pFSH group vs. 6.42 ± 0.13 and 6.19 ± 0.15 for rhFSH3 and pFSH3, respectively; P<0.05). Otherwise, females treated with pFSH5 protocol, only a 24.3% of ova developing into hatched blastocyts after in vivo fertilization, compared to an average of 80.4% for control group. Thus, it is possible that, after this superovulation treatment, the oocyte metabolism would be affected.

	The third experiment was designed in order to assess the efficiency of in vivo oocyte  and embryo recovery after a recombinant human FSH (rhFSH) treatment in rabbit does. With this aim, in vivo laparoscopy technique was used in order to collect the oocytes (16 hours after ovulation induction) and the embryos (72 hours after artificial insemination) in superovulated and non-superovulated females. Up to four recoveries were performed with each doe. Recovery efficiencies differed significantly between embryos (84%) and oocytes (58%). Yet, the recovery rates for the superovulation and control groups did not differ. Moreover, the recovery efficiency after the four treatments did not decrease, therefore, results from this study indicate that repeated in vivo oocyte and embryo recovery from rhFSH superovulated does maximizes the number of oocytes or embryos collected from the same female.

   	The last experiment was performed in order to evaluate the effect of  macromolecules addition (PVA and dextran) in rabbit embryo vitrification media, using Ethylene-glycol and Dimethyl-sulfoxide as cryoprotectants. There was a significantly higher proportion of embryos without damages in mucin coat or zona pellucida after warming (undamaged embryos) in the control than in the superovulation group (95.8% vs. 83.2%, respectively). The addition of dextran to the vitrification media improve the preservation of rabbit embryos and permits to reduce the amount of DMSO for vitrification. Additionally, in vitro developmental ability of undamaged embryos were not affected by superovulation treatment nor vitrification media.