Feline colonic morphology and mucosal tissue energetics as influenced via the source of dietary fiber

Twenty-eight adult female cats were used to assess the effects of dietary f iber on feline colonic morphology, mucosal cell density and tissue energeti cs. Three sources of dietary fiber (i.e., cellulose, beet pulp and a pectin /gum arabic blend) and a non-fiber control diet were compared. The fiber so urces were selected according to their degree of fermentation and degradati on within the colon of the domestic cat and dog. The feeding of the non-fer mentable, cellulose diet, resulted in greater colonic weight and colonic we ight per kg body weight when compared to those cats receiving the non-fiber , control diet. Colonic mucosal surface area to colonic mass ratio was sign ificantly increased for all fiber diets (cellulose > beet pulp > pectin/gum arabic) when compared to the non-fiber diet. The colonic crypt depth and c rypt width values were not altered by the addition of fiber to the diet. Ho wever, the addition of fiber to the diet significantly increased colonic mu cosal energetics (per gram of tissue), and the individual mucosal cell ener getics (per unit DNA), when compared to the non-fiber fed cats. Contrary to the noted increase in colonic surface area associated with the decrease in fermentability of the fiber source, the addition of the more fermentable f ibers enhanced the colonic mucosal cell energetics (i.e., pectin/gum arabic > beet pulp > cellulose > non-fiber diet). While dietary fiber is not a "n atural component" of domestic cat diets, the increase in colonic weight and in mucosal cell activity resulting from the addition of fiber are suggesti ve of enhanced colonic health. (C) 2000 Elsevier Science Inc.