Effect of different transport temperatures of cattle and sheep ovaries on in vitro maturation of oocytes

Abstract

The aim of study is to determine the effects of different transport temperatures (4 degrees C, 32 degrees C) of sheep and cattle ovaries on the in vitro maturation of oocytes. Two experimental groups were formed. Sheep and cattle ovaries were put into saline solution at 32 degrees C. The ovaries were transported to the laboratory, at the same temperature (Group I) or at 4 degrees C following 10 minutes of incubation at room temperature (Group II) (n=6). Oocytes were collected from ovaries using the dissection method. Oocytes matured in their own group in 700 ml TCM-199 (supplemented with pyruvate, LH, FCS) for 23 h at a gas atmosphere of 5% CO2, 5% O2, 90% N2 and at 38.8 degrees C. After maturation, oocytes were fixed in acetic acid-ethyl alcohol (1:3) for 48 hours. The stages of development up to MII, of the oocytes stained with aceto-orsein were then examined. The Chi-Square test was used for statistical analysis. While in the VC group, sheep oocytes reached 30.6% (MI), 15.3% (MII) and cattle oocytes reached 17.3% (MI), 46.8% (MII), in the 32 degrees C group these percentages were respectively 38.3%, 33.1% in sheep and 19.3%, 55.4% in cattle. While oocytes obtained from sheep ovaries transported at 32 degrees C reached the MIII stage at a higher rate compared to those at 40C (P < 0.001), no statistically significant difference was observed between maturation to the MII stage of oocytes obtained from cattle ovaries transported at 4 degrees C and 32 degrees C. As a result of this study, it was established that cattle ovaries could be transported both at +4 C, +32 degrees C and that there was no difference in oocyte maturation.