137 PHENAZINE ETHOSULFATE AND FETAL CALF SERUM EFFECTS ON THE DEVELOPMENT AND APOPTOSIS OF IN VITROPRODUCED BOVINE EMBRYOS.

Phenazine ethosulfate (PES) is a metabolic regulator that inhibits fatty acid synthesis and favours the pentose-phosphate pathway. Supplementation of fetal calf serum (FCS) during culture has been correlated with the reduction of quality of in vitroproduced bovine embryos (IVPE). The aim of the present study was to evaluate embryo development and apoptosis in blastocysts after the supplementation of PES and FCS in culture medium of IVPE. Oocytes (N=4320) were matured and fertilized in vitro(Day 0). The zygotes (Bos indicus) were cultured in SOFaa medium with 4 concentrations of FCS (0, 2.5, 5, and 10%) and with the use or not of 0.3μM PES from Day 4 (after 96h of embryo culture). Embryo development was evaluated after 7 days of culture. Apoptosis in blastocysts (N=60–80) was accessed through TUNEL reaction. Embryos (Bos indicus) recovered from superstimulated cows were used as in vivocontrol (n=15). Data were analysed by ANOVA followed by LSD using PROC GLIMMIX (SAS; SAS Institute Inc., Cary, NC, USA) means±SEM. Increasing FCS concentration in the culture media did not change cleavage (86.7±1.7, 82.3±1.6, 86.3±1.4, 87.0±1.5, P>0.05) and augmented blastocyst production (30.5±2.5a, 41.8±2.4b, 40.5±2.6b, 47.2±2.8b, P0.05) cleavage (87.0±1.3 and 84.4±1.3), blastocyst production (42.0±2.8 and 43.0±2.0), and apoptosis in blastocysts (20.7±2.0band 18.9±2.1b), respectively, for control and PES Day 4 groups. Independent of FCS withdrawal or PES addition to culture medium, the in vivocontrol group presented the lowest apoptosis rate (6.3±1.1a). Therefore, increasing FCS concentration augmented embryo development and reduced blastocyst quality. However, the addition of 2.5% of FCS in the culture medium increased the embryo development without the reduction of blastocyst quality. Moreover, the PES supplementation from Day 4 did not affect embryo development and blastocyst quality. São Paulo Research Foundation – FAPESP. [ABSTRACT FROM AUTHOR]