Effects of pre- and post-mating nutritional status on hepatic function, progesterone concentration, uterine protein secretion and embryo survival in Meishan pigs

This experiment examined whether the pre- or the post-mating diet had great er impact on embryo survival in Meishan gilts. Gilts received either a main tenance (1.15 kg day(-1); n = 12) or a high (3.5 kg day(-1); n = 12) diet d uring the oestrous cycle preceding mating. After mating, half the animals i n each group received either the maintenance or the high diet until slaught er on Day 12. Gilts fed the high premating diet had more corpora lutea (22. 7 v. 19.0, SED = 0.98; P < 0.001), increased embryo survival(95.5% v. 74.8% , SED = 7.58; P < 0.01) and heavier corpora lutea(-0.71 log g v. -0.90 log g, SED = 0.09; P = 0.07) compared with gilts fed the maintenance diet prior to mating. The post-mating diet had no effect on embryo survival. There we re no treatment effects on blastocyst developmental stage, luteal surface a rea or progesterone release. Gilts receiving the high post-mating diet had heavier livers than those fed the maintenance post-mating diet (1.45 v. 1.0 8% of total bodyweight, SED = 0.07; P < 0.001), suggesting that these gills have a greater capacity to metabolize progesterone. Pre-mating nutritional status therefore appears to be a greater determinant of embryo numbers and survival than the post-mating diet.