CARBOHYDRATE-METABOLISM OF THE CAT .4. ACTIVITY OF MALTASE, ISOMALTASE, SUCRASE AND LACTASE IN THE GASTROINTESTINAL-TRACT IN RELATION TO AGE AND DIET

In 26 adult European shorthaired cats and 32 kittens (newborn to 12 weeks of age) the activity of maltase, isomaltase and sucrase in the small intestinal mucosa was investigated. In some of the adult animals their activity in pancreatic tissue, chyme, feces and large bowel mucosa was also tested. Disaccharidases were determined by liberation of glucose from disaccharides, the activity was given per gram protein determined in the mucosa. Diet (carbohydrate-free ration, high starch diets with 29-37% starch, high sugar diets with either 36% sucrose or 28% lactose in dry matter) did not influence disaccharidase activity. Maltase, isomaltase and sucrase did not depend on age either (maltase adults 102 +/- 58, newborn 66 +/- 77, isomaltase 35 +/- 28 and 30 +/- 20 resp., sucrase 17 +/- 23 in adults and 15 +/- 8 U/g protein in newborn kittens). In contrast to that lactase activity decreased from 96 +/- 66 U/g protein in newborn kittens to 13 +/- 9 U/g protein in 6 week old kittens (adult cats 7 +/- 8). In few adult cats there was a lactase activity in the jejunum considerably above the average (up to 53 U/g protein). In pancreatic tissue a low activity of maltase and isomaltase was detectable but neither lactase nor sucrase. In chyme and feces all disaccharides tested (maltase, sucrase, lactase) were apparent in a low activity. In the mucosa of the large bowel their activity was in a similar range like in the chyme and feces.