Development of Intestinal Disaccharidase Activities in Nursing Calves

1. The disaccharidase activities of mucosal homogenates from the small intestine, caecum and colon of cattle were observed. 2. In nursing calves, lactase, cellobiase and trehalase activities were located mainly in the upper part of the small intestine, whereas maltase and isomaltase activities were more uniformly distributed along the small intestine and were also found in the caecum and colon. Intestinal cellobiase, trehalase, maltase and isomaltase activities were very low compared with lactase activity and intestinal sucrase activity was not detected. 3. Intestinal lactase, cellobiase and trehalase activities were the highest at birth and decreased rapidly with age. These activities increased during the late fetal period. On the other hand, intestinal maltase and isomaltase activities showed no increase during the late fetal period and nursing period of 6 months, 4. Relatively low pH values of intestinal contents of 5.5-6.0, which were close to optimum pH of intestinal disaccharidases, were observed in the upper part of the small intestine. 5. In adult cattle, intestinal lactase and cellobiase activities were found but only with negligible levels. Intestinal trehalase activity was also found with low level. Intestinal maltase and isomaltase activities were found to be similar levels to those found in calves. Intestinal sucrase activity was not detected. 6. Based on the results of disaccharidase activities and tissue weights, overall utilizable quantities of lactose and maltose by small intestinal mucosa in nursing calves were estimated.