Effect of oestrous cow serum from superovulated animals on in vitro bovine embryo production and on progesterone synthesis of granulosa cell monolayers
1999
Pereira, R.M. | Vasques, M.I. | Marques, C.C. | Baptista, M.C. | Horta, A.E.M.
The effects of two types of oestrous cow serum added to in vitro culture media (OCS - natural oestrus; SOCS - superovulated oestrus) on embryo production co-incubated with granulosa cell monolayers, were studied. Both sera were collected 24 hours after the onset of heat. The following parameters were evaluated and compared: oocyte cleavage rate after IVF, percentage of D8 and hatched embryos, embryo development rate between 7th and 9th days of culture, D8 embryo quality (ranging from 1-excellent and 4-poor), and progesterone production by granulosa cell monolayers. The rates of oocyte maturation, cleaved oocytes, D8 and hatched embryos were not different between OCS and SOCS groups. Within D7 embryos there was significantly more expanded embryos in SOCS than in OCS (54,8% vs. 38,9%, respectively, P0.055) and less embryos in the blastocyst stage (9.6% vs. 22.2%, respectively, P0.037). Within classes of D8 and D9 embryos there was only a tendency for the proportion of embryos in later stages of development being higher in the SOCS group. At D8, the proportion of grade 1 embryos was significantly higher in SOCS than in OCS group (13.1% vs. 1.4%, respectively, P0.007). Concerning progesterone production by granulosa monolayers, the concentration found beyond 4 days of culture was significantly higher in SOCS than in OCS group. The results above show that the addition of oestrous cow serum from superovulated animals (SOCS) to the culture media, when compared with normal oestrous cow serum (OCS), accelerales the growth rate of in vitro co-cultured embryos and improves the quality of D8 blastocysts. This effect seems to be related to a higher luteinizing effect of SOCS on granulosa cell monolayers, suggesting a direct or mediated effect of luteotrophic substances present in SOCS on a faster embryo growth and better quality of transferable embryos
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