Postprandial Hyperketonemia after Feeding of Alcoholic Fermented Apple Pomace Silage in Suffolk Ewes

Apple pomace silage (APS) contains a considerable amount of ethanol. Two experiments were conducted to investigate the effect of feeding APS ethanol on response of blood parameters in Suffolk ewes. Four ewes were fed alfalfa hay cube and either rice straw APS (RS-APS, 33.4 g of ethanol/kg DM) or concentrate at 30:70 of TDN requirement in a 2 × 2 crossover design in experiment 1. In experiment 2, we compared low and high ethanol APS (44.1g vs. 66.9 g of ethanol/kg DM) in the same experimental design. In experiment 1, plasma concentrations of ethanol, lactate and B-hydroxybutyrate (BHBA) increased after feeding in RS-APS treatment (P < 0.01, P < 0.05 and P < 0.05; respectively). Plasma insulin level tended to increase (P = 0.06) after RS-APS feeding but the magnitude of postprandial glucose decline did not differ between treatments. The area upper or under the curves (AUCs) of plasma ethanol (P < 0.01) and lactate (P < 0.05) were positively correlated with that of BHBA. Insulin AUC was positively correlated (P < 0.01) with AUCs of ethanol and BHBA. In experiment 2, changes in the blood parameters showed similar trends after feeding of two APSs but no significant treatment effect was detected. The AUC of BHBA was positively correlated (P < 0.01) with that of lactate. Glucose AUC was negatively correlated (P < 0.05) with AUCs of lactate and BHBA. According to the consistent increase in plasma ethanol and BHBA after feeding of APSs, positive correlation of BHBA with lactate and/or ethanol and negative correlation of glucose with lactate and BHBA, we concluded that APS ethanol consumption induce postprandial transient hyperketonemia through suppression of hepatic gluconeogenesis.