Assessment of morphological integrity and in vitro developmental competence of vitrified buffalo oocytes

Abstract

In the present study, a total of 399 ovaries collected from slaughtered buffaloes were aspirated for the recovery of cumulus-oocyte complexes (COCs). The recovered COCs were subjected to in vitro maturation (IVM) to assess their survivability following vitrification and subsequent thawing (devitrification). After maturation, oocytes were partially denuded and vitrified using the Vitrogen vitrification kit with different exposure times, followed by storage in liquid nitrogen (LN₂). Devitrification was performed using the Vitrogen devitrification kit according to the standard protocol. Morphological evaluation of devitrified COCs revealed a significantly higher proportion of normal COCs in the control group (87.37%) compared to vitrified Group I (70.79%) and Group II (65.66%). Correspondingly, the proportions of damaged COCs were 12.63%, 29.21%, and 34.34% in the control, Group I, and Group II, respectively. Among the damaged COCs, the percentages of zona crack, cytoplasmic leakage, shrunken ooplasm, presence of fewer than five vacuoles, and more than five cytoplasmic vacuoles were 0.00%, 0.00%, 50.00%, 16.67%, and 33.33% in the control group; 69.23%, 19.23%, 38.46%, 53.85%, and 11.54% in Group I; and 52.94%, 14.71%, 47.06%, 50.00%, and 20.59% in Group II, respectively. Statistical analysis indicated a significant difference (p