Soybean hulls as a dietary fiber source for dogs

In Exp. 1, soybean hull samples were obtained from nine sources across the United States and analyzed for nutrient content to determine their suitabil ity for inclusion in dog diets. Compositional data revealed variation in bo th the amount of total dietary fiber (TDF; 63.8 to 81.2%) in the soybean hu lls and the ratio of insoluble:soluble fiber (5.0:1 to 15.4:1). Crude prote in content varied widely among sources, ranging from 9.2 to 18.7%. An in vi vo trial (Exp. 2) was conducted using a premium dog diet containing 3.0, 4. 5, 6.0, 7.5, or 9.0% soybean hulls (DM basis). There was a negative linear effect (P < .05) of soybean hull inclusion in the diet on DM, OM, TDF, and GE total-tract digestibilities, as well as on calculated ME. Crude protein and fat digestibilities were unaffected by treatment. Based on these result s, ileally cannulated dogs were fed diets containing 6.0, 7.5, or 9.0% soyb ean hulls (DM basis) in addition to diets containing either 0% supplemental fiber or 7.5% beet pulp (Exp. 3). Nutrient digestion at the ileum was unaf fected by inclusion of supplemental fiber. Total tract digestion of DM, OM, and GE was lower ( P < .05) for diets containing supplemental fiber when c ompared with the diet containing 0% fiber. Crude protein and fat digestibil ities were unaffected by treatment. There was no difference in nutrient dig estibility between those diets containing soybean hulls and a diet containi ng beet pulp. Soybean hull inclusion in the diet resulted in a negative lin ear effect (P < .05) on calculated ME, in addition to lowering ME (P < .05) when compared with the 0% fiber control diet. Calculated ME for dogs fed a 7.5% beet pulp-containing diet was lower (P < .05) than that for dogs fed the soybean hull-containing diets. Results indicate that soybean hulls can be an effective dietary fiber source in dog diets.