ELSEVIER HIGH BOVINE BLASTOCYST DEVELOPMENT IN A STATIC IN VITRO PRODUCTION SYSTEM USING SOFaa MEDIUM SUPPLEMENTED WITH SODIUM CITRATE AND MYO-INOSITOL WITH OR WITHOUT SERUM-PROTEINS P. Holm,’ P.J. Booth,’ M.H. Schmidt,’ T. Greve’ and H. Callesen’ ‘Embryo Technology Center, Danish Institute of Agricultural Sciences DK-8830 Tjele, Denmark *Department of Clinical Studies, Royal Veterinary and Agricultural University DK-1870 Frederiksberg, Denmark Received for publication: 1 I Januarv 1999 Accepted: 7 >iav 1999 ABSTRACT We describe a bovine embryo culture system that supports repeatable high development in the presence of serum or BSA as well as under defined conditions in the absence of those components. In the first experiment, embryo development in SOF with amino acids (SOFaa), sodium citrate (SOFaac) and myo-inositol (SOFaaci) and with BSA or polyvinyl alcohol (PVA) was compared with that in a Ml99 granuloaa cell co-culture (Ml99 co-culture). Subsequently, development and cell numbers of blastocysts cultured under defined conditions in SOFaaci with PVA (SOFaaci-PVA), or under undefined condltiis in SOFaaci with 5% cow serum (SOFaaci- CS) or Ml99 co-culture were compared. The repeatability of culture results in SOFaaci-CS was checked by weekly replicates (n=30) spread over 11 months. The viability of embryos developed in SOFaaci-PVA was estimated by transfer of morphologically good blastocyats (n=lO) to synchronized recipients. In the second experiment, the effect of omitting CS or BSA from IVM and IVM-IVF on subsequent embryo development in SOFaaci-PVA or in SOFaaci-CS was investi ated. f! Blastocyst development in SOFaa-PVA, SOFaac-PVA, SOFaa-BSA and Ml99 was 16 f 3 , 23 + 2*, 30 rt 8a and 36 + 7’?&, respectively (Pab< 0.05). Additional inclusion of myo- inositol resulted in 42 It la% blastocysts in SOFaaci-PVA vs 19 + 3b% in SOFaac-PVA, 47 + 7a% in SOFaac-BSA, and 38 + 7a% in Ml99 co-culture, respectively (Pab< 0.01). In 30 replicates, the average cleavage and blastocyst rates of oocytes in SOFaaci-CS were 87 + 4 and 49 + 5%, respectively. Five normal calves were produced after transfer of 10 blastccysts developed in defined culture medium (i.e., SOFaaci-PVA). Defined IVM or IVM-IVF (i.e., in absence of CS and BSA) reduced cleavage rates (83 + 3 and 55 + 3% vs 90 + 1% in presence of CS; P < 0.01). Subsequent embryo development in SOFaaci-CS was not affected in either of these defined conditions. However, cleavage and blastocyst rates under completely defined IVP conditions were 54 + 7 and 19 + 4%, respectively. It was concluded that under defined culture conditions, addition of citrate and myo-inositol improved blastocyst development to rates comparable to those obtained with serum, BSA or co-culture and that the quality of blastocysts was not affected by the absence of serum or BSA. However, serum was essential during IVMIIVF for normal fertilization and subsequent high blastocyst development. 01999by ElsevierScience Inc. Key words: cattle, IVP, embryos, synthetic oviduct fluid, defined medium Acknowledgments The authors thank Annette Pedersen and Klaus Villemoes for technical assistance. Theriogenology 52383-700, 1999 cb 1999 by Elsevier science Inc OO95691W99/$-see front matter PII SOOQ3-691X(99)00162-4