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Báo cáo khoa học: "Effect of Reproductive Status on In Vitro Developmental Competence of Bovine Oocytes"

Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Effect of Reproductive Status on In Vitro Developmental Competence of Bovine Oocytes | J. Vet. Sci. 2003 4 1 67-72 JOURNAL OF Veterinary Science Effect of Reproductive Status on In Vitro Developmental Competence of Bovine Oocytes Kazim R. Chohan and Alan G. Hunter Division of Theriogenology College of Veterinary Medicine University of Minnesota Saint Paul MN 55108 USA Received November 19 2002 Accepted February 11 2003 Abstract The objectives of the present study were to compare the in vitro maturation IVM fertilization and early embryonic development of bovine oocytes recovered from ovaries during the follicular met-estrus and diestrus stages of the estrous cycle and at anestrus and pregnancy after m aturation in a serum free culture medium . Cumulus oocyte com plexes COCs collected from ovaries at different reproductive statuses were matured in medium 199 supplemented with 10 g ml FSH 10 g ml LH 1.5 g m estradiol 75 g ml streptomycin 100 IU ml penicillin and 10 mM HEPES. COCs were incubated in 200 droplets of maturation medium 199 under oil for 24 h at 39 c and 5 CO2 Matured oocytes were exposed to frozen-thaw ed TALP swim up heparin capacitated sperm from tw o bulls separately in each replicate 20 h 39C 5 CO2 . After fertiliz ation the presum p tive zygotes were cultured in medium 199 containing 8 mg ml BSA-V 100 IU ml penicillin-G 75 g ml streptomycin and 10 mM HEPES for 144 h at 39C and 5 CO2 w ithout m edium freshening or ch an ge. Oocy-tes embryos were fixed stained with DAPI and evaluated under fluorescent microscope. The IVM rates were alm ost sim ilar among oocytes from all reproductive statuses ran ge 89.8 to 95.4 . How ever IVM rates for oocytes from the metestrus 90.6 and pregnant 89.9 phases were lower than the other groups. The fertiliz ation rates w ere low er p 0.05 for oocytes from the diestrus phase 72.4 than from the other phases range 81.1 to 86.6 . Oocytes recovered during the m etestrus phase of the estrous cycle resulted in the highest cleavage rate 60.0 w hile oocytes from the diestrus phase had the poorest em bryonic .