Use of Rat Estrus Serum for in Vitro Maturation of Bovine Oocytes

Superovulation produces complications in some patients, so invitro maturation of oocytes is used to decrease or eliminate these complications and improve IVF. Moreover, IVM is used for different aspects of reproductive researches. Slaughterhouse ovaries are the main source of oocytes for IVM and IVF studies. Different media has been introduced and experimented for in vitro maturation of oocytes. Animal's serum at estrus stage contains different hormones and proteins which are essential for oocyte maturation. The aim of this study was to compare three culture media for in vitro maturation (IVM) of bovine oocytes 1)(control)TCM-199, 2)HCG and follicular fluid (FF) and 3) antibiotic.

Rat estrus serum (RSS) or fetal bovine serum (FBS) was added to control medium. Total of 1789 compact cumulus oocyte complexes (COCs) were aspirated from ovaries of slaughtered animals. Oocytes were randomly cultured in mentioned media and incubated in 38.5◦c, 5% CO2 and 95% humidity for 24 hours. The maturation of oocytes was judged according to cumulus cell expansion or randomly orcein stained oocytes and observation of polar bodies.

The results showed that maturation rate was significantly higher in second and third group (90.2%, 78.7%) as compared to the control group (p<0.001). There was no significant difference between second and third groups (90.2 % vs. 86.6%).

RSS is as effective as FBS for IVM of bovine oocytes and can be used as an alternative.