CARBOHYDRATE-METABOLISM OF THE CAT .1. ACTIVITY OF AMYLASE IN THE GASTROINTESTINAL-TRACT OF THE CAT

Adult cats were fed 3 different high starch diets (cooked or raw maize starch, raw potato starch; 30-37% starch in dry matter) or carbohydrate-free control diets. Amylase activity was determined in pancreas, chyme and feces. Several characteristics of pancreatic and fecal amylase (pH-optimum, particle binding, bacterial sediment activity, stability in acid solutions, effect of in-vitro-fermentation) were investigated as well as the impact of high doses of oral antibiotic treatment (500 mg ampicillin, 75 mg clindamycin, 12.5 mg enrofloxacin/cat/d) on fecal amylase activity. Chymotrypsin was determined in chyme, feces, and after in-vitro-fermentation. Amylase activity in pancreas and small intestine was moderate to low (pancreas 75 U/g, chyme from the small intestine 10-50 U/g wet weight). Inductive effects of dietary starch were small. After long-term feeding of maize starch the activity in the small intestine was doubled. Amylase activity decreased in the caudal parts of the intestine and in feces. Studies of the characteristics of fecal amylase (similar to pancreatic amylase), effects of oral antibiotics (no change) and in-vitro-fermentation on fecal amylase activity (decrease) showed clearly, that most of the gastrointestinal amylase of cats is of pancreatic origin.