The in vitro production of pig embryos has achieved unsatisfactory results; in vivo matured oocytes produce a higher percentage of embryos compared to in vitro maturation. The success of in vitro maturation is directly related to oocyte competence. Only competent oocytes are capable of being fertilized and have normal embryonic development. The oocyte competence can be assessed using several parameters. Recently these parameters have been used for gene expression studies associated with competence. This work aimed to evaluate differences in gene expression BMP15, RYBP, MATER, ZAR1 as endogenous control and the constitutive gene GAPDH in immature oocytes of different morphological classes which are: 1, 2, 3 and 4, in order to provide significant molecular markers linked to the ability of development. Oocytes Total RNA was extracted and used as a template for synthesis of the first cDNA strand. The results of gene expression were analyzed using a mixed model, considering the dependent gene expression data and independent ovocitary variable classes. The genes BMP15, RYBP ZAR1 and showed similar ovocitary expression in classes 1, 2 and 3 differ only in category 4 in their expression (P<0.05). The MATER gene was similarly expressed in all ovocitary classes studied (P>0.05). The RTQ-PCR technique was effective for detection of these transcripts in oocytes from different classes. However, for better understanding of the involvement of these transcripts in the acquisition of oocyte competence more studies are needed to evaluate different morphological classes of oocytes at different stages of development and the implication of other genes involved in oocyte competence.
pigs; developmental competence; cumulus-oophorus complex; citoplasmic maturation; nuclear maturation