Assessment of parthenogenetic embryo production by activation of in vitro matured caprine oocytes with different concentrations of ethanol

The objective of this study was to compare the effectiveness of different concentrations of ethanol treatment for activation of oocytes and their developmental potency in vitro. Ovaries were collected from a local abattoir and transported within 4 h to the laboratory in warm saline (37 °C) containing 100 IU penicillin-G and 100 μg streptomycin sulphate per ml. A total of 2680 cumulus oocyte complexes (COCs) were collected from 899 ovaries. Oocytes were matured in TCM-199 medium containing FSH (5 μg/ml), LH (10 μg/ml), supplemented with 20% fetal bovine serum at 38.5 °C and 5% CO2 in an incubator under humidified air for 27 h. After 27 h of IVM, oocytes were denuded, washed and randomly divided into five groups. Group 1 consisted of in vitro matured oocytes (n = 403) as control which were washed with KSOM medium without ethanol. Group 2 consisted of in vitro matured oocytes (n = 412) activated with 1% ethanol for 5 min in KSOM medium. Group 3 was comprised of in vitro matured oocytes (n = 362), activated with 1% ethanol for 5 min in KSOM medium. Group 4 was comprised of in vitro matured oocytes (n = 564) activated with 5% ethanol for 5 min in KSOM medium. Group 5 consisted of in vitro matured oocytes (n = 634) activated with 7% ethanol for 5 min in KSOM medium. Group 6 consisted of in vitro matured oocytes (n = 305) activated with 9% ethanol for 5 min in KSOM medium. After 5 min activation, the oocytes were washed 5-10 times in the culture medium (KSOM) and cultured in 50 μl drop of KSOM. Development of activated oocytes was observed at every 24 h till day 10 post insemination under inverted phase contrast microscope (200×, Nikon, Japan). The percentage of cleavage and morula production in groups 1, 2, 3, 4, 5 and 6 were 0.00% and 0.00%, 0.00% and 0.00%, 8.28% and 6.66%, 10.43% and 26.31%, 33.19% and 29.26%, 40.32% and 14.63%, respectively. These results suggested that the activation of in vitro matured oocytes by 7% ethanol for 5 min in KSOM is most favorable for parthenogenetic caprine embryos production.