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.
