author(s)
Dipannita Baishya, Arundhati Bora, Anubha Baruah, DJ Dutta, Champak Barman and Shantanu Tamuly

abstract
The present experiment was conducted to investigate the effect of insulin-like growth factor-I on in vitro maturation, fertilization and early embryonic development of cattle oocytes. A total of 318 nos. bovine ovaries were collected from slaughter houses for one year and 1089 nos. culturable oocytes were collected. 357 out of 1089 nos. culturable oocytes, were subjected to IGF-I supplemented serum and serum free basic maturation media. There was no significant difference in respect of maturation, fertilization and embryonic development between IGF-I supplemented serum and serum free basic maturation as well as culture media. The mean percentage of in-vitro maturation of bovine oocytes (IVM) based on cumulus cell expansion was found to be significantly higher (P<0.05) in serum basic maturation media without IGF-I (75.43 ± 3.25) than the serum free basic maturation media with IGF-I (67.27 ± 6.33) respectively. The mean cleavage percentages at 4-cell, 8-cell, 16-cell, morula & blastocyst stages of embryos in serum culture (without IGF-I) and serum free culture media (with IGF-I) were recorded as 47.25 ± 4.86 and 57.14 ± 4.83, 31.87 ± 4.99 and 45.71 ± 4.86, 20.88 ± 3.21 and 37.14 ± 4.72, 7.69 ± 4.32 and 27.62 ± 4.36 & 4.40 ± 2.09 and 4.76 ± 2.08 respectively but the mean cleavage percentages recorded at 4-cell, 8-cell, 16-cell and morula stages of embryos in IGF-I supplemented serum free culture media were found to be significantly higher (P<0.05) than in serum culture media (without IGF-I) and after that the differences were found to be statistically non-significant. Similar findings were also observed in serum free culture media with or without IGF-I. From the present experiment, it can be inferred that addition of IGF-I in serum free maturation media had little beneficial effect than serum basic maturation media. Though the addition of IGF-I in serum and serum free culture media had beneficial effect on post fertilization period but the in vitro blastocyst production in IGF-I supplemented serum free culture media was comparable to serum free media without IGF-I.