EFFECTS OF PROTEIN-SOURCE AND COCULTURE ON BOVINE EMBRYO DEVELOPMENT IN SYNTHETIC OVIDUCTAL FLUID MEDIUM

Experiment 1 compared the development of 2- to 4-cell bovine embryos c ultured in synthetic oviductal fluid with 20% fetal calf serum or 3.2% BSA and in the presence of oviductal cells, cumulus cells, or medium alone. More embryos developed in medium with serum, regardless of cult ure method (P = 0.063). Oviductal cell co-culture resulted in more emb ryos developing to at least the morula stage (P less than or equal to 0.066). The number of blastocysts was increased by the use of serum in stead of BSA in cumulus cell co-culture medium (P < 0.001). Regardless of culture method, a similar percentage of embryos were excellent or good quality when BSA was used in medium (P greater than or equal to 0 .400). Addition of serum to oviductal cell co-culture medium increased the number of excellent or good quality embryos (P = 0.019). Experime nt 2 further compared the development of 2-cell or 3- to 4-cell embryo s co-cultured with oviductal cell suspensions in serum-supplemented sy nthetic oviductal fluid or M-199 medium. More 3- to 4-cell than 2-cell embryos developed to at least the morula stage (P < 0.001). More embr yos developed to at least the morula stage in synthetic oviductal flui d (P = 0.083). Neither initial embryo cell stage nor medium type influ enced the percentage of developing embryos that achieved the blastocys t stage or final morphological quality of embryos (P greater than or e qual to 0.535).