The detrimental effect of pregnancy-associated bile acid homeostasis disorder on fetal pig death

The objective of this study was to determine bile acid metabolism and its association with fetal pig death in pregnant gilts. A total of 430 gilts/sows with similar genetic background (LandracexYorkshire) were included in this study, 407 of them from parity 1 to 9 were selected to evaluate the critical time of fetal death, 12 gilts implanted with cephalic vein catheters were used to determine the relationship of bile acid metabolism with fetal death, and additional 11 pregnant gilts at gestation day 60 (G60) and 90 (G90), respectively, were sacrificed at 8h postprandial for determination of mechanism accounting for disrupted bile acid homeostasis and fetal death. Pregnant gilts had raised serum total bile acids (TBA), which reached peak levels (7.10- 67.00 pmol/L) at G90, and was ~1-8 time that at G60 (4.10-20.00 pmol/L). Moreover, fetal death predominantly occurred during late pregnancy, with 70.67% of dead fetuses observed from G76 to farrowing. Fetal mortality was positively correlated with the increasing of TBA ratio of G90/G60, and significant difference in fetal survival appeared between the ratio "6" gilts (7.6% vs 28.6%, P