CONICET | Buscador de Institutos y Recursos Humanos

It has been postulated that porcine cumulus oocyte complexes (COCs) use amino acids as oxidative substrates during in vitro maturation. However, those reports have been developed in media which contain diverse energetic substrates, so the use of each of them could have been overlapped. The aim of this work was to study the implication of amino acids (Aa) as unique oxidative substrates during porcine oocyte maturation in vitro. Immature cumulus-oocyte complexes (COCs) were obtained by aspiration of antral follicles from slaughtered gilts and then classified under a stereomicroscope according to the characteristics of their cumulus. Only oocytes surrounded by a dense and integer cumulus were selected and then randomly distributed into 5 groups: NCSU-37 without pyruvate or glucose, NCSU-37 + glucose, NCSU-37 + Aa, NCSU-37 + Aa + glucose and NCSU-37 + Aa + salicylate (Aa catabolism inhibitor). All the groups were matured for 44h at 39ºC, 5% CO2 and 100% humidity. To determine meiotic maturation percentages oocytes were denuded and then stained with Hoechst 33342 solution. The nuclear status of each oocyte was analyzed using an epifluorescence microscope with 330-380 (excitation) and 420 (emission) filters at x125 and x400. To evaluate Aa catabolism we used a spectrophotometric assay based on NADPH oxidation by glutamate dehydrogenase, quantifying the residual ammonia in each maturation medium. These data were expressed as ammonia production/COC/minute. Meiotic maturation percentages were compared using a Chi-square analysis for non-parametric data. The levels of residual ammonia in the maturation media were expressed as mean ± standard error mean and their interactions were analyzed by two-way ANOVA, using post-hoc general contrasts for comparison among treatments. Values with a p