Effects of Crude Protein and Carbohydrate in Dry Foods on Apparent Digestibility in Adult Cats

Two digestion trials were conducted to examine effects of CP and carbohydrate in dry foods on apparent digestibility in adult cats. Apparent digestibility was determined by both total feces collection method and chromium oxide (Cr₂O₃) indicator method. In trial 1,12 adult cats were divided into three groups of four cats each, and three diets with different CP contents were randomly allotted to the three groups. Apparent digestibility of DM, CP and AEE tended to decrease with increasing dietary CP contents independent of the measuring method. In trial 2,12 adult cats were divided into three groups of four cats each, and following three diets were randomly allotted to the three groups to evaluate effects of dietary carbohydrate. The control diet contained no carbohydrate sources, the starch diet contained corn as a starch source, and the fiber diet contained beet pulp, cellulose powder and wheat flour as a fiber source. Apparent digestibility of DM, CP and NFE was lower in the fiber diet group than in the other two groups, independent of the measuring method. In contrast apparent digestibility of NFE was higher in the starch group. There were no striking differences among the groups on the differences between apparent digestibility determined by both measuring methods. The present results suggest that dry food with lower CP content causes irregular flow of the intestinal digesta. In contrast, dietary carbohydrate (NFE plus crude fiber) seems to have minimal effects on the intestinal digesta flow in of adult cats.