Evaluation of four times of maturation in vitro in alpaca oocytes on the rate of maturation and embryonic development

Abstract

The objective was to evaluate the maturation time to obtain oocytes in Metaphase II (MII) stages and the rate of division and blastocysts after fertilization in alpacas. For this, the ovaries were obtained from benefited animals. Experiment 1: 441 oocytes were distributed in four times (26, 32, 38 and 42 hours) and matured in TCM-199. At the end of the maturation time, the oocytes were fixed in an ethanol solution: acetic acid (3:1) and stained with aceto-orcein (1%). Experiment 2: 959 oocytes were cultured under the same conditions as experiment 1 and fertilized with sperm obtained by artificial vagina and selected by the Swim Up method. At the end of the fertilization time, the presumed zygotes were cultured in SOFaa medium for 7 days. In experiment 1, 39.6 ± 8.0, 49.1 ± 18.6, 45.9 ± 9.1 and 38.2 ± 9.9% of oocytes were obtained in Metaphase-II for 26, 32, 38 and 42 h of maturation, respectively, without statistical difference (p>0.05). In experiment 2, the cleavage rate was 45.7 ± 3.5, 51.3 ± 10.2, 52.8 ± 5.6 and 50.9 ± 3.1 with no statistical difference between treatments (P>0.05) and the blastocyst rate was 20.5 ± 3.4, 30.5 ± 5.8, 21.2 ± 2.5 and 22.8 ± 3.5 for 26, 32, 38 and 42 hours, respectively, with a statistical difference between 32 hours and 26, 38 and 42 hours (p<0.05). The results obtained suggest that 32 hours of maturation are required to obtain 30.5% of blastocysts