Effect of Different Growth Factors on in vitro Developmental Competence and Quality of Cattle Oocytes

The developmental competency of in vitro matured oocytes to the blastocyst stage is a big concern in laboratory conditions. This study aims in finding the best combination of growth factors for enhancement of cleavage as well as early embryonic developmental rates in cattle.

Fresh cattle ovaries were obtained from the nearest slaughterhouse in 0.15 M freshly prepared saline (35-38°C) supplemented with penicillin (400 IU/ml). A total of 924 COCs were aspirated from ovaries and transferred to maturation media for incubation (5% CO₂) at 38.5°C with maximum humidity for 24 h. After maturation, the matured oocytes were co-incubated with the capacitated sperms for in vitro fertilization in the FBO medium for 16 h. After fertilization, the cumulus cells were removed from the presumptive zygotes and incubated in the mCR2aa medium for 45-48 h. The cleavage rates of the zygotes were observed and further cultured in the blastocyst medium for 7-10 days. After every 24 h, 80% of culture media was replaced with fresh media. Three different combinations of growth factors (PDGF+IGF, EGF+FGF and T₃+T₄) used in this study.

Supplementation of growth factors in culture media increased cleavage rate and blastocyst rate significantly (p<0.05). PDGF+IGF @ 10 ng/ml+75 ng/ml, EGF+FGF @ 20 ng/ml+10 ng/ml and T₃+T₄ @ 100 ng/ml+100 ng/ml showed the best results in terms of cleavage rates and blastocyst development.