Effect of Zinc and Nano Zinc on Developmental Competence of Buffalo Oocytes

This study aimed to investigate the impact of zinc sulfate and nano zinc oxide on the In-vitro maturation (IVM) of oocytes and on the In-vitro embryo developmental competence of buffaloes. Ovaries were obtained from the abattoir. Good quality oocytes (excellent & good) were matured in tissue culture medium -199 (TCM-199) vs. TCM-199 +10-6M zinc sulfate vs. TCM-199 +10-6 M nano zinc oxide enriched by fetal calf serum 10% (FCS) + 10 μg/ml follicle-stimulating hormone + 50 μg/ml gentamicin. The oocyte maturation was done in the incubator for 22 h in a humidified environment with CO2 5% and 38.5°C. Frozen-thawed semen was used to fertilize Mature oocytes, which were then incubated for 18 hours, before being cultured by synthetic oviduct fluid (SOF) for 7 days. The obtained results showed that supplementing maturation medium with 10-6 M zinc sulfate and 10-6 M nano zinc oxide resulted in a significant (P˂0.05) rise in GIII cumulus cell expansion of buffalo oocytes by 52.93 %, and 59.75%, respectively, as compared to oocytes cultured in free medium (36.8%). G0 cumulus cell expansion showed a significant (P˂0.05) decrease in zinc sulfate and nano zinc oxide groups (7.85, 3.29 %, respectively) when compared with oocytes cultured in free medium (14.73 %). The rate of maturation of oocytes with polar bodies was significantly greater in the zinc sulfate and nano zinc oxide groups (86.98, and 92.43%, respectively) when compared with those matured in free medium (80.11%). The hatching (cleavage) rate was significantly greater (P˂0.05) in the zinc sulfate and nano zinc oxide groups (83.17, 87.66 respectively %) when compared with the TCM-199 (free medium) group (78.60%). The transferable embryos (blastocyst & morula) rates significantly raised (P˂0.05) in the zinc sulfate (17.28 & 19.87 %, respectively) and nano zinc oxide groups (21.23 &26.21%, respectively) when compared with TCM-199 group (11.19 &13.75 %, respectively). In conclusion, in vitro maturation rate and transferable embryo rates in buffaloes improve by adding zinc sulfate and nano zinc oxide to the medium of maturation.