Insulin-like Growth Factor-1 Supplementation and Early Embryonic Developmental Competence of Immature Cattle Oocytes

Background: The livestock industry is a growing field where assisted reproductive technologies like in vitro embryo production (IVEP) enhance production efficiency. However, in vitro embryos show lower developmental competence due to stress and suboptimal culture conditions. Supplementing culture media with growth factor, such as insulin-like growth factor-1 (IGF-1) can improve embryo development. This study investigates the effect of IGF-1 on the developmental competence of oocytes and early embryonic development. Methods: In this study, cattle oocytes were aspirated from 3-8 mm ovarian follicles, washed and matured in maturation media supplemented with different concentrations of IGF-1 (0, 10, 25, 50, 100 ng/ml) for 24 hours at 38.5oC 5% CO2. Frozen-thawed sperm were used for in vitro fertilization of matured oocytes in fertilization media supplemented with IGF-1. Presumptive zygotes were cultured in IGF-1-supplemented mCR2aa media and embryos were monitored for 8 days until the blastocyst stage. The experiment was replicated six times and data were statistically analyzed by one-way ANOVA followed by Duncan Multiple Range Test using SPSS. Results are presented as means±standard error with graphs generated by GraphPad Prism. Result: IGF-1 @ 50 ng/ml significantly enhanced embryo development, with highest cleavage rates at 2-cell (85.35% ±2.24) and 4-cell (86.10% ±1.90) stages and improved morula (32.53% ±5.11) and blastocyst formation (15.81%±1.07) and IGF-1 @ 100 ng/ml showed moderate benefits, while at lower concentrations i.e. 0 ng/ml, 10 ng/ml and 25 ng/ml had minimal effects. Overall, @ 50 ng/ml IGF-1 was the most effective in promoting oocyte maturation and early embryonic development.