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

Three types of starch (cooked maize starch = MSc, raw maize starch = M Sr, raw potato starch = PSr, starch intake 4.7-8.9 g/kg body weight) w ere tested for total and prececal digestibility as well as for the imp act of starch on digestion of protein and fat, intestinal and fecal mi lieu (pH, dry matter content, organic acids, osmolality, buffering cap acity, ammonia, in-vitro-gas production from feces) in 6 digestion tra ils 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 additiona l feeding trials were carried out under high-dosed oral antibiotic tre atment (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 tha n total digestibility, but is showed a similar pattern (MSc 72, MSr 46 , PSr 0%). Protein digestibility decreased in group MSr and PSr. Fat d igestibility increased after the intake of raw starch. Starch led to a n acidification of large bowel chyme and feces, and effect which was a lleviated by oral antibiotics. The concentration of organic acids was influenced by starch feeding or antibiotics. In-vitro-gas production f rom feces was higher after starch feeding.