-210 Nottingham - Nottingham eTheses - The University of Nottingham

(PZM; Yoshioka et al., 2002), as discussed in Chapter 1. NCSU-23 with BSA is
considered as a good embryo culture medium and Onishi et al. (2000) reported the
higher frequency of the blastocyst formation supported by culture in NCSU-23 than
BECM-3 and mWM. However, Yoshioka et al. (2002) showed that PZM containing 3
mg/ml of BSA (PZM-3) produced developmental results than NCSU-23, causing
higher proportion of Day 6 blastocysts, frequency of Day 8 hatching blastocysts,
numbers of inner cell mass (ICM) cells and total cells in Day 8 embryos. In culture
with PZM-3, embryo development was reported to be optimised in an atmosphere of
5% C02: 5% 02: 90% N2. So in these studies, PZM-3 was chosen for further porcine
embryo culture.
In the experiment, which chemical had better parthenogenetic developmental potential
between oocytes synchronised by CHX and cAMP was determined. This was to
follow the experiments carried out in Chapter 3, which showed that cAMP was more
effective in synchronising porcine oocyte maturation than CHX. No significant
differences existed among cleavage and parthenogenetic development (about 30% of
the frequency of blastocyst formation) of control, CHX and cAMP treated oocytes. It
showed synchronisation of porcine oocytes by treatment with either CHX or cAMP
did not affect subsequent parthenogenetic development of selected oocytes if judged
by the blastocyst formation, although the total cell numbers of CHX treatment were
higher than those of cAMP treatment (P < 0.05).
However, cAMP offered better efficiency of synchronising porcine IVM
and
significantly more matured oocytes at 44 hpm with far better cumulus expansion,
which could be beneficial for cytoplasmic maturation of the oocytes and lead to
cumulus removal easier for enucleation. That is to say, far more MII oocytes could be
selected for further experiments. Also, cAMP produced a more homogenous (less
aged) population of oocytes as compared to unsynchronised controls
(Chapter 3).
Therefore in the following experiments, CAMP was selected to synchronise oocytes.
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