IN-VITRO MATURATION OF OVINE OOCYTES IN A PORTABLE INCUBATOR

Immature ovine oocytes were collected from ovaries obtained from an ab attoir and assigned to one of three treatment groups for in vitro matu ration. For Treatment 1 (T1), oocytes were matured in a conventional i ncubator, in tissue culture wells in an atmosphere of 5% CO2 and air. Maturation medium consisted of bicarbonate buffered Tissue Culture Med ium 199 (TCM199) supplemented with fetal calf serum (FCS), follicle st imulating hormone (FSH), luteinizing hormone (LH), and penicillin/stre ptomycin (pen/strep). For Treatment 2 (T2), oocytes were matured in a portable incubator, in plastic tubes containing the same medium as T1. The medium was equilibrated with 5% CO2 and overlayed with oil. For T reatment 3 (T3) oocytes were matured in the portable incubator without CO2 equilibration, in tubes containing HEPES buffered TCM 199 supplem ented as in T1. After 24 hours at 39 degrees C,the percentage of oocyt es undergoing normal nuclear maturation was 72.55, 68.14 and 66.96% fo r T1, T2 and T3, respectively (P>0.05). In a second experiment oocytes were matured in the 3 treatments described, then fertilized in vitro using frozen-thawed ram sperm. Fertilization rates were 44.09, 58.62 a nd 55.69% for T1, T2 and T3, respectively. T1 and T2 were significantl y different (P<0.05). For Experiment 3, oocytes matured and fertilized as described were cultured in drops of Modified Brinster's Mouse Ova Culture (MBMOC) containing bovine oviductal cells. These were incubate d at 39 degrees C in an atmosphere of 5% CO2 and air for 7 days. T1, T 2 and T3 resulted in 20.26, 16.94 and 24.43% development to morulae, a nd 4.01, 3.06 and 1.85% development to blastocysts, respectively (P>0. 05). The results of these experiments indicate that maturation, fertil ization, and developmental rates of ovine oocytes matured in the porta ble incubator are similar to those of oocytes matured in a conventiona l incubator. This technique shows promise for transportation of oocyte s to laboratories where abattoirs are not in close proximity, and hold s promise for transportation of oocytes from non-domestic animals coll ected in the field or remote locations, to facilities capable of utili zing and preserving the gametes. (C) 1997 by Elsevier Science Inc.