Effect of increasing intakes of Zn, Cu, and Mn on their secretion via bile and pancreatic juice and their excretion in faeces and urine in sheep fed lucerne pellets

Abstract

Abstract Twelve Romney Marsh wethers, 6 with cannulae placed into their bile and pancreatic ducts, were used. Zn intake was increased from 19.6‐730.0 mg/day, Cu from 6.78‐17.78 mg/day, and Mn from 24.1‐178.0 mg/day. 75 to 94% of the microelements consumed were excreted in the faeces, and the major route ofloss, of those examined, of the absorbed Zn and the absorbed Cu and Mn was via the pancreatic juice and bile secretions respectively. Smaller amounts of Zn, Cu, and Mn were excreted in the urine. Increasing the microelement intake increased the Zn, Cu, and Mn losses from all routes of excretion and secretion except the Cu in the bile which was influenced by a Zn‐Cu interaction. The losses from the body were not great enough to prevent an increase in the apparent retention of Zn, Cu, and Mn or the 2‐fold increase in the plasma Zn levels and Zn content ofthe liver and kidney. The high intake of microelements (the available evidence suggests the Zn) damaged the exocrine cells of the pancreas and also significantly decreased the secretion rate of bile and pancreatic juice.