Effects of different culture and oocyte conditions on the first polar body extrusion of cattle oocytes
For investigating PB1 extrusion of cattle’s oocytes under different component concentrations of culture solution,culture methods in vitro and oocytes derivation,COCs suctioned from abattoir-derived ovarian follicles were cultured under different situations.Results showed that the culture conditions in vitro promoted PB1 extrusion of cattle’s oocytes significantly(P0.05).The optimized components added in the culture medium were 10 μg·mL-1 FSH,10 μg·mL-1 LH,1.0 μg·mL-1 17-β E2 and 33.0 μg·mL-1 sodium pyruvate,and the optimized culture time in vitro was 24 h;culture density was 10-20 COCs per 50 μL of the culture solution;temperature of ovaries storage and transportation were at 25-37℃,and transportation time was less than 3 h;the ovarian follicle diameter was 3-6 mm;and the oocytes covered 2 layer cumulus cells would well matured.The maximum available PB1 provided research basis for protecting species,improving genetic resources of excellent females and preimplantation genetic diagnosis in the future.