THE SPECIATION OF LYSINE-COMPLEXED COPPER AS A BOVINE NUTRITIONAL SUPPLEMENT

Copper deficiencies in ruminants can be corrected by administering eit her free (inorganic) or complexed (chelated) copper. Chelated forms ar e thought to be more bioavailable as they are more stable, and may the refore be absorbed intact. Formation constants for the complexes betwe en copper and the different ligands in the digestive tract can be used to predict if the chelate does, in fact, remain intact. Using a gravi metric autotitrator, the various complex formation constants for the c opper(II) lysine system were determined at 38 degrees C, the temperatu re of the rumen environment. Formation constants for copper(II) comple xes with the amino acids glycine and histidine were also determined at 25 and 38 degrees C. The formation constants for the copper(II) lysin e system were then utilized in computer simulations to determine the f ate of the complex prior to arriving at the rumen. The speciation of t he copper(II) lysine system was determined in McDougall's solution, a simulated form of bovine saliva. Results suggest that if copper is adm inistered as copper lysine ''chelate,'' this will disintegrate and the copper will be present mainly as carbonate and phosphate complexes.