Effects of pre- and post-mating feed intake on blastocyst size, secretory function and glucose metabolism in meishan gilts.

This experiment was designed to determine the effects of a nutritional regime, known to increase embryo survival, on blastocyst development and function. Day 12 blastocysts were recovered from Meishan gilts allocated in a 2x2 factorial design to receive either a high or a maintenance diet before or after mating (n = 4-6 gilts per group). The post-mating diet had no effect on individual blastocyst size, cell number, secretion of oestradiol-17beta or retinol binding protein, glucose metabolism or on the within-litter variability in these measures. Blastocysts recovered from gilts consuming the high pre-mating diet had more cells (13.501 v. 13.006 log cells; SED = 0.23; P = 0.05), greater production of CO2 from glucose (2.19 v. 1.23 log pmol(-1) blastocyst(-1) 3 h(-1), SED = 0.42; P = 0.05) and a lower within-litter standard deviation in blastocyst surface area (0.66 v. 1.18 log mm2, SED = 0.24; P = 0.04) compared with gilts fed the maintenance pre-mating diet. Collectively, these data suggest that a nutritional strategy that increases embryo survival is also associated with an increase in individual blastocyst cell number and reduced within-litter variability in blastocyst size.