To test if arginine and ornithine, both components of the Krebs-Henseleit
cycle, or zeolite, a potential ammonium absorber, can modulate the excretion
of harmful bacterial metabolites, intestinal microbial protein fermentation
was stimulated by feeding a high-protein (60.3%) diet as a single daily meal
to 10 adult cats. The diet was supplemented without or with arginine (+50, 75,
100% compared to arginine in the basal diet), ornithine (+100, 150, 200%
compared to arginine in the basal diet), or zeolite (0.125, 0.25, 0.375 g/kg
body weight/day). The cats received each diet for 11 days. Urine, feces, and
blood were collected during the last 4 days. Arginine and ornithine enhanced
the postprandial increase of blood urea, but renal urea excretion was not
increased. Zeolite decreased renal ammonium excretion and fecal biogenic
amines. The data indicate an increased detoxification rate of ammonia by
arginine and ornithine supplementation. However, as urea was not increasingly
excreted, detrimental effects on renal function cannot be excluded. Zeolite
had beneficial effects on the intestinal nitrogen metabolism, which should be
further evaluated in diseased cats. Clinical studies should investigate
whether dietary arginine and ornithine might improve hepatic ammonia
detoxification or could be detrimental for renal function
