Development Compatence of Sheep Oocyte with Diferent Duration Time and Temperature Storage of Ovary

Abstract

The present study was conducted to investigate the effects of storage time and temperature of sheep ovaries on nuclear maturation of oocyte and in vitro fertilization rate of oocytes. The ovaries were stored in physiological saline for 2- 4 h, 5-7 h and 8-10 h at 27-28°C, 36-37°C and 4°C respectively. There was no difference between the proportions of oocytes that underwent maturation to metaphase II when collected from ovaries stored at 27-28°C and 36-37°C for 2-7 h of slaughter (P>0.05). However, the percentages of oocytes from ovaries stored at 4°C were significantly lower than those of oocytes stored at higher temperature (69.23%, and 70.83%, 45.65%, for 27-28°, 36-37° and 4° C at 2-4 h, respectively; 59.61%, and 64,58%, 36.36%, for 27-28°, 36-37° and 4° C at 5-7 h, respectively) (P<0.05). The proportion of oocytes underwent meiosis to MII were significanly decreased when the ovary stored at 27-28°C and 36-37°C for 8-10 h but not in oocytes collected from ovaries stored at 4°C (24.37%, 7.84% and 45.23%, respectively) (P<0.05). There was no difference between the proportions of fertilization when collected from ovaries stored at 27-28°C, 36-37°C and 4°C for 2-7 h of slaughter (53%, 66,66% and 63%, resperctively) (P>0.05). Same phenomena showed for fertilization rate of oocyte that the ovaries storage for 5-7 h. However fertilization rate decrease when storage for 8-10 h. The prensentage of fertilization rate were 9,8%, 22,22%, 12,24% respectively for 27-28°C, 36-37°C dan 4°C. Our finding indicate that the storage of ovaries at 27°C-28°C, 36-37°C for 5-7 h is effective for maintaining the developmental competence of sheep oocytes compare with 4°C.