EFFECTS OF FETAL CALF SERUM, AMINO-ACIDS, VITAMINS AND INSULIN ON BLASTOCOELE FORMATION AND HATCHING OF IN-VIVO AND IVM IVF-DERIVED PORCINEEMBRYOS DEVELOPING IN-VITRO/

The objective of this study was to determine the effects of fetal calf serum (FCS), non-essential MEM amino acids, MEM vitamins and insulin on blastocoel formation, expansion and hatching in porcine embryos dev eloping in vitro. Addition of 20% FCS to the NCSU 23 medium significan tly (P < 0.05) decreased by the compaction and blastocoel formation of 1- to 2-cell embryos developing in vitro. In contrast, more 1- to 2-c ell embryos commenced hatching in the media containing amino acids tha n in control medium (25.7 vs 2.6%, P < 0.01). Amino acids and insulin synergistically enhanced the incidence of blastocoel formation and hat ching of porcine embryos developing in vitro (P < 0.05). When early co mpacted embryos which developed in vitro in NCSU 23 medium were cultur ed in BSA-free NCSU 23 medium supplemented with 20% FCS, the incidence of hatching was significantly increased compared with that of the con trol groups (35.7 vs 4.1%, P < 0.01). However, addition of amino acids , vitamins or insulin to the NCSU 23 medium did not enhance the develo pment of early morulae to the hatched embryos (P > 0.1). When either i n vivo or IVM/IVF-derived 1- to 2-cell stage embryos were cultured 4 d in the modified NCSU 23 and an additional 4 days in the modified NCSU 23 supplemented in the FCS, the percentages (61.8 and 17.8%, in vivo- and IVM/IVF-derived, respectively) of hatched blastocysts were signif icantly higher (P < 0.01) than in the control groups (2.9 and 0%, in v ivo and IVM/IVF-derived, respectively). These results suggested that d ual culture conditions are required to optimize an in vitro culture sy stem for the development of the porcine embryo in vitro. (C) 1997 by E lsevier Science Inc.