Effect of sporidesmin-induced liver damage in ewes before mating on growth of the foetus and placenta

Abstract

Sporidesmin is a fungal toxin commonly found in pasture. It causes liver damage in sheep that resembles cholestasis in humans. We determined whether pre-mating sporidesmin-induced liver damage in ewes might provide a useful approach to the experimental induction of intrauterine growth restriction (IUGR). Romney ewes were drenched with sporidesmin extracts. Affected ewes (SP, n=44) and controls (CN, n=42) were mated. Sporidesmin treatment decreased pregnancy rate (non-pregnant; SP 43% vs. CN 12%, twin; SP 23% vs. CN 52%, both P<0.05). SP foetuses were 6% lighter than CN foetuses at 89 days of gestation, but not at 134 days. Increasing maternal plasma gamma glutamyl transferase activities at mating were associated at 89 days with reduced maternal weight (-1.1: -1.9, -0.3 kg/100 U/l, mean effect size: 95% confidence intervals), increased visual liver damage and reduced placentome number (-1.4: -2.7, -0.1/100 U/l) and foetal pancreatic weight (-21: -38, -4 mg/100 U/l). They were also associated at 134 days with reduced weight of the foetal pancreas (-132: -221, -42 mg/100 U/l), spleen (-139: -231, -47 mg/100 U/l) and thyroid (-29: -48, -10 mg/100 U/l) and decreased A-type placentomes (-3.0: -5.0, -1.0/100 U/l). Pre-mating sporidesmin-induced liver damage is not useful for induction of experimental IUGR but does impair the growth of the foetal pancreas, spleen and thyroid and alter placental morphometry.