137 Comparison of two invitro maturation media on polar body extrusion of cattle oocytes

Abstract

The invitro embryo production technique is one of the assisted reproduction technologies that has the potential in speeding up genetic improvement in cattle. The developmental competence of invitro-matured oocytes is influenced by several factors during invitro maturation (IVM), such as maturation environment, oocyte quality, type of media, and additives. The objective of the present study was to compare two IVM media (TCM-199 and BO-IVM) on cattle oocyte maturation rate invitro. Cattle ovaries were collected from local slaughterhouse and transported to the laboratory in a thermos flask containing 0.9% saline (Adcock Ingram Critical care) at 37°C. Oocytes were retrieved from the ovaries by the aspiration technique, and then matured invitro in 500µL of TCM-199 (supplemented with 10% fetal bovine serum, FSH, LH, and E2) or in 500µL of commercially available BO- IVM (Bioscience) medium, both covered with mineral oil for 22h at 38.5°C with 5% CO2 and 5% O2. After 22h of IVM, oocyte polar body extrusion was evaluated with the aid of Oosight Imaging System (Hamilton Thorne) connected to an inverted microscope. The total number of oocytes matured in TCM-199 and BO-IVM media were 401 and 396, respectively. The experiment was replicated 19 times. Data were analysed using the GenStat® program (VSN International). Means of different treatments were separated using Fisher’s protected t-test least significant difference at 5% level of significance. No difference was recorded for polar body extrusion rates in TCM-199 (50.6±13.9) and BO-IVM (47.3±13.7) media. In conclusion, TCM-199 and BO-IVM media did not differ in terms of maturation rate; thus, both can be used for successful cattle oocyte IVM.