Produção in vitro de embriões bovinos com soro de égua em diferentes fases do estro

Abstract

In vitro embryo production (IVP) is an attractive technique because of the low-cost production of numerous bovine embryos, use in somatic cell and embryo cloning, production of transgenic cows, as well as for basic research. Protein in the culture media appeared to be one of the most significant limiting factors in the different steps of this technology. These protein sources are represented mostly by biological materials which provide nutrients and other poorly understood factors for the embryos. This study evaluated the possibility of using mare´s serum obtained at different stages during oestrus for bovine in vitro production. Complexes cumulus-oocytes (CCO) from slaughtered cows ovaries were matured in a controlled incubator (39ºC, 5%CO 2 , saturated humidity) for 22-24h in TCM-199 + HEPES + bLH + hFSHr + 10% mare serum collected at the 1 st day of oestrus (T1), 24-48h before ovulation (T2) and 24-48h after ovulation (T3) and a control group (C), using the same medium added 10% oestrus cow serum. In vitro fertilization (IVF) was performed in TALP-FERT under the same conditions and in vitro culture (IVC) on synthetic oviduct fluid (SOF)+5% of T1, T2, T3 or C serum, during 8 days under mineral oil. Cleavage rates were similar between treatments. Blastocyst rates at D7 were higher (T1=21%, T2=21% and T3=20%; P <0.05) than the controls (12%). Hatching rates in T1 (9,8%-47/477) were higher (P<0.05) than T2 (3.1%-15/477), T3 (4.2%-21/505) and C (4.1%-20/486). Hatched blastocysts of T3 had a lower (P<0.05) number of cells than those of T1 and Control. Considering it´s heterologous nature, the possibility of preventing disease transmission and the higher blastocyst rates at D7 reported here, the use of oestrus mare´s serum can be used for the IVP of bovine embryos.

Handmade cloned bovine embryos, parthenogenesis and in vitro fertilization: a comparison

“…In the present study, the number of blastomeres in the blastocytes formed following IVF was significantly greater than in the embryos activated parthenogenetically and in the cloned embryos (109.8 vs. 73.7, 78.1 and 77.5). The observed values are equivalent to or greater than those obtained in other studies in both in vitro fertilized embryos and cloned bovine embryos (Totey et al, 1996;Figueiró et al, 2002). This indicates that the applied system of production is efficient in both the production of blastocytes and the obtained embryo quality, defined based on the number of blastomeres (Im et al, 2006).…”