Table 2. Effects of mineral oil overlay on embryo development of oocytes matured in vitro
Mineral oil preparation Total number of zygotes % Cleavage (n) % Blastocysts (n) % Hatching (n)*
72 hpi 168-192 hpi
CMO 110 82.2 (74) a 40.0 (36) a 94.4 (34) / 37.8 (34) a
WMO 90 80.9 (89) a 31.8 (35) a 71.4 (25) / 22.7 (25) b

hpi: hours post-insemination. Different superscript letters in the same column indicate a significant difference (chi-square test; *Fisher test, P < 0.05). *Hatching rates: calculated from the number of blastocysts/and presumptive zygotes, respectively.