Dietary trial using a commercial hypoallergenic diet containing hydrolyzed protein for dogs with inflammatory bowel disease.

Six dogs with inflammatory bowel disease (IBD) received a commercially available hypoallergenic diet containing an enzymatically hydrolyzed defatted soy globulin as the only protein source. Five of the six dogs had been refractory to a variety of controlled diets, and four dogs had failed to respond to previous medical therapy. All dogs were fed the test diet twice daily for 10 weeks. Dogs not showing adequate improvement in clinical signs after 2 to 4 weeks on diet alone had appropriate medical therapy added to the dietary regimen. Gastroduodenoscopy and biopsy were performed on Day 0 and repeated at the conclusion of the study. Intestinal biopsies were evaluated by a pathologist using a numeric grading scheme to describe histologic alterations and mucosal architecture. Dietary therapy alone provided adequate clinical improvement in four dogs, and concurrent medical therapy was required in two dogs, one of which had exocrine pancreatic insufficiency. Mean fecal scores improved after therapy. Five dogs showed mild to moderate histologic improvement in duodenal biopsies after therapy. The clinical improvement observed cannot be solely attributed to the hydrolyzed nature of the protein source because the diet tested was highly digestible, contained cornstarch (rather than intact grains) and a source of medium-chain triglycerides (23% of fat), and had an altered ratio of omega-6 to omega-3 polyunsaturated fatty acids. Nevertheless, the resolution of clinical signs and improved biopsy scores demonstrate the importance of conducting further studies to critically assess the role of diets containing a hydrolyzed protein source for the management of dogs with previously refractory IBD.