Viabilidad y morfología de ovocitos bovinos de ovarios de matadero de acuerdo al diámetro folicular

Abstract

The objective was to evaluate the viability and morphology of bovine oocytes from follicles of different sizes. The follicles were measured and classified in group 1(<4 mm), group 2(4-8 mm) and group 3(>8 mm), these were aspirated with a 21G needle connected to a vacuum pump (pressure 65 mmHg). According to the cells of the system and the cytoplasm, the COCs were classified as suitable and not suitable for PIV. The BCB test was applied to determine the activity of the G6PD enzyme. The maturation in micro drops with a TCM199 base medium in an incubator at 38.5 °C, 5% CO2 and 90% humidity, for 24 hours. The assessment of meiotic progression to metaphase II was determined with the Hoesch stain (33342Sigma), visualized using a fluorescent inverted microscope. The diameter of the oocytes was measured before and after maturation. G2 presented a higher percentage of COC subjects (65.7%), followed by G3 (54.9%) and G1 (42.4%) (P <0.05). It was determined that 59.0% of COCs of G2; 44.6% of G1 and 35.7% of G3 were found as BCB + (P <0.05), however G2 presented more BCB + than BCB- (P <0.05). Finally, the oocytes, as fit for G1 and G2, reached metaphase II in 75%, unlike G3 (61%), (P <0.05). Also, after maturation, the three groups, the oocytes, decreased their diameter. It is concluded that the COC´s from follicles between 4 and 8 mm have a higher percentage of oocytes that culminated the growth and reached maturity.