In vitro production of Bos taurus indicus embryos with cysteamine

ABSTRACT

Advanced reproductive techniques use three phases of bovine embryos in in vitro production (IVP), i.e. in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) for a variety of studies. This study assessed the effect of cysteamine, a thiol component, on the embryonic development during IVP. Bos taurus indicus cumulus-oocyte complexes (COC) from ovaries collected at an abattoir were randomly distributed in four groups control-group (n = 544; without cysteamine), cysteamine in maturation (n = 543), cysteamine in fertilization (n = 540) and cysteamine in the culture medium (n = 557). All COC were matured for 24 h in TCM-199 + 0.01 IU r-hFSH/ml + 0.05 mg LH/ml + 10% fetal calf serum (FCS) at 38.5ºC in 5% CO2 in humidified air. In the cysteamine-maturation group, the TCM-199 medium was supplemented with 150 µm cysteamine (CYS). The IVF (day 0 = fertilization day) was performed for 18-22 h in Fert-Talp medium + heparin + penicillamine, hypotaurine and epinephrine (PHE). The medium of the cysteamine-fertilization group was supplemented with 150 µm CYS. Bos taurus indicus frozen semen was selected by Percoll gradient, and incubated with the oocytes for 18 h. Presumed zygotes were cultured in 400 µl SOFaaci medium + 5% FCS. In the cysteamine-culture group the SOFaaci was supplemented with 150 µm CYS. Embryos were cultured at 5% CO2, 5% O2, 90% N2 and saturated humidity for 8 days. Cleavage rates were 86, 90, 88, and 91%respectively, for control, maturation, fertilization and culture groups. The blastocyst yield at day 7 was 29, 29, 38 and, 36% (P < 0.05) hatched blastocyst yield at day 9 was 21, 25, 27, and 29% (P < 0.05) in the control group and treatments, respectively. Results demonstrated that the addition of cysteamine to the fertilization or culture medium improved blastocyst production.(AU)