CARBOHYDRATE-METABOLISM OF THE CAT .2. DIGESTION OF STARCH

Three types of starch (cooked maize starch = MSc, raw maize starch = MSr, raw potato starch = PSr, starch intake 4.7-8.9 g/kg body weight) were tested for total and prececal digestibility as well as for the impact of starch on digestion of protein and fat, intestinal and fecal milieu (pH, dry matter content, organic acids, osmolality, buffering capacity, ammonia, in-vitro-gas production from feces) in 6 digestion trails and 5 post-mortem-experiments in 56 adult cats. Three carbohydrate-free diets, 1 high-protein (PROT) and 2 high-fat diets (FATc and FATr) served as controls. To eliminate effects of the microflora additional feeding trials were carried out under high-dosed oral antibiotic treatment (500 mg ampicillin, 75 mg clindamycin, 12.5 mg enrofloxacin/cat/d). MSc was digested to nearly 100%, MSr to 78%, PSr to 36%. Prececal starch digestibility (determined post mortem by marker) was lower than total digestibility, but is showed a similar pattern (MSc 72, MSr 46, PSr 0%). Protein digestibility decreased in group MSr and PSr. Fat digestibility increased after the intake of raw starch. Starch led to an acidification of large bowel chyme and feces, and effect which was alleviated by oral antibiotics. The concentration of organic acids was influenced by starch feeding or antibiotics. In-vitro-gas production from feces was higher after starch feeding.