The effects of ethanol, androgens and maturation system on bovine embryo development and sex ratio
Previous literature suggested that steroids, particularly androgens might play a role a biasing the sex ratio (%male) of developing embryos towards maleness. The purpose of this study was to determine if addition of androstenedione and testosterone to oocyte maturation media altered sex ratio. To maximize hormone availability, the maturation process was modified, 00 was removed, and plastic and glass containers were compared. Ethanol was the vector of hormone delivery, and was tested at increasing concentrations to determine if an ethanol effect was present. Finally, both hormones were tested at levels above and below physiological averages in follicular fluid. The ethanol-glass interaction caused a decrease in sex ratio from the expected 50% male rate. Only the sub-physiological dose of androstenedione coincided with a sex ratio shift in favour of females. Cleavage rates were decreased in glassware, blastocyst rates improved with steroid addition, and oocytes could mature, fertilize and develop normally in concentrations of ethanol of 10%, but not 20%.