Alterations in Liver Enzyme Activities and Blood and Urine Metabolite Levels during the Onset of Thiamine Deficiency in the Dairy Calf

Abstract

A combination of physiological, clinical and enzymatic criteria was used to characterize the onset of thiamine deficiency in male Holstein calves fed a purified diet lacking thiamine. Deficiency symptoms appeared between 27 and 48 days after eliminating thiamine from the diet and 24 to 45 days after thiamine excretion had decreased to below 0.05 mg/day. Concomitantly with the appearance of overt deficiency symptoms, blood pyruvate and lactate levels increased from 1 and 15 mg/100 ml to 5 and 100 mg/100 ml, respectively; urinary pyruvate excretion increased from 15 mg/day to over 50 mg/day. Average blood hemoglobin and hematocrit levels were significantly depressed, 16 and 22%, respectively. The activities of transketolase and anaerobic pyruvate dehydrogenase decreased to 50 and 30% of control values. Aldolase activity increased at the time of the clinical symptoms relative to that of controls, whereas malic enzyme, isocitrate dehydrogenase, and glucose-6-phosphate dehydrogenase activities apparently were not altered. Refeeding thiamine corrected all the deficiency symptoms.