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Effects of maturation and co‐culture treatments on the developmental capacity of early bovine embryos
Author(s) -
Wiemer Klaus E.,
Watson Andrew J.,
Polanski Voyteck,
McKenna Ann I.,
Fick Gordon H.,
Schultz Gilbert A.
Publication year - 1991
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080300407
Subject(s) - biology , andrology , zygote , oocyte , embryo , human fertilization , blastocyst , in vitro maturation , in vitro fertilisation , in vitro , embryogenesis , fetal bovine serum , medicine , endocrinology , anatomy , biochemistry , genetics
A total of 901 cumulus–oocyte complexes (COCs) were collected from bovine ovaries obtained at a local abattoir. COCs randomly assigned to Treatment I (n=451), were cultured in TCM‐199 + 10% fetal bovine serum (FBS) and hormones, while oocytes in Treatment II (n=450) were cultured in TCM‐199 + 20% estrous cow serum (ECS). Assessment of maturation revealed that 91.3% (42/46) of oocytes in Treatment I had reached metaphase II of meiosis, which was greater ( P <0.05) than the 73.3% (33/45) in Treatment II. Following in vitro fertilization, 203 oocytes from Treatment I were co‐cultured on bovine granulosa cells (Treatment IA) while the remaining 202 oocytes were co‐cultured on bovine oviductal cells (Treatment IB). Similarly, 203 oocytes from Treatment II were co‐cultured on granulosa cells (Treatment IIA) or oviductal cells (Treatment IIB, n = 202). Co‐culture was maintained for 8 days. The proportion of cleaved zygotes was higher ( P <0.05) in Treatment IB (86.6%) compared to Treatments IA (78.8%), IIA (58.1%), and IIB (64.8%). The proportion of cleaved zygotes that progressed beyond the 16‐cell stage was also greater (P <0.001) in Treatment IB (71.4%) compared to Treatments IA (50.0%), IIA (35.4%) and IIB (55.8%). Treatment IB also produced the highest proportion of blastocysts ( P <0.0001) (41.1%) versus 24.6% (IA), 11.3% (IIA) and 18.3% (IIB). The proportion of day 6 morulae that progressed to form day 8 blastocysts was similar for both co‐culture treatments (IA, 70.1%; IB 70.2%; IIA, 51.5%; IIB 50.8%) and varied only between in vitro maturation groups. Results indicate that the combination of in vitro maturation in TCM‐99 + 10% FBS and hormones followed by co‐culture on oviductal monolayers is a superior system for the production of early bovine embryos.