Intestinal Absorption of Homologous Lactic Dehydrogenase Isoenzymes by the Neonatal Pig

Abstract

Enzymatic activity is generally more susceptible to alteration than other measurable characteristics of a protein. The present experiments were designed to test whether it was possible to feed enzymes to neonatal pigs and have the enzymatic activity survive the alimentary secretions and the passage through the intestinal epithelium. Absorption of enzymes may have some relevance with respect to postnatal maturation. The well-characterized isoenzymes of lactic dehydrogenase (LDH) were the ones followed in this study. Homogenates of adult porcine liver, heart muscle, and skeletal muscle (each with a distinct isoenzyme electrophoretic pattern) were fed to neonatal pigs. The criterion for absorption was an early and marked increase in the blood serum LDH activity of piglets fed tissue homogenates plus a shift of the isoenzyme serum electrophoretic pattern toward that of the fed tissue. Such changes in total activity and electrophoretic pattern were observed in our piglets fed the homogenates versus controls fed a salt solution. It was concluded that the young of certain species can absorb proteins with retained enzymatic activity.