Colonic mucosal tissue energetics and electrolyte transport in dogs fed cellulose, beet pulp or pectin/gum arabic as their primary fiber source

Abstract

Fifteen adult beagle dogs were used to assess the effects of dietary fiber (cellulose, beet pulp and pectin/gum arabic) on the canine colonic mucosal DNA content, energetic activity and electrolyte transport systems. The fiber sources were selected according to their relative colonic fermentability (i.e. cellulose is limited, beet pulp is moderate and pectin/gum arabic is highly fermentable). Mucosal tissues of dogs fed the cellulose diet had significantly more DNA (ug/mg of tissue) than that of those fed the beet pulp or pectin/gum arabic fiber sources. However, dogs fed the pectin/gum arabic diet had significantly greater mucosal energetic activity (umol O 2 · g −1 · min −1) per unit DNA than did the other two fiber sources. While the proportion of organic acid absorption was not statistically different among treatment groups, dogs fed the beet pulp absorbed more acetate than propionate or butyrate. However, the feeding of pectin/gum arabic resulted in greater butyrate absorption. The results of this study in conjunction with three earlier studies clearly suggest that; feeding dogs beet pulp (a moderately fermentable fiber source) provided not only an modest and appropriate colonic SCFA concentration but also the more optimal acetate, propionate and butyrate fermentation/absorption pattern, when compared to cellulose and pectin/gum arabic.