IBD has been defined clinically as a spectrum of gastrointestinal disorders associated with chronic inflammation of the stomach,
intestine and/or colon of unknown etiology. A clinical diagnosis of IBD is considered only if affected animals have: (1) persistent
(>3 weeks in duration) gastrointestinal signs (anorexia, vomiting, weight loss, diarrhea, hematochezia, mucousy feces), (2)
failure to respond to symptomatic therapies (parasiticides, antibiotics, gastrointestinal protectants) alone, (3) failure
to document other causes of gastroenterocolitis by thorough diagnostic evaluation, and (4) histologic diagnosis of benign
intestinal inflammation. Small bowel and large bowel forms of IBD have been reported in both dogs and cats, although large
bowel IBD appears to be more prevalent in the dog.
Treatment – Management of IBD consists of 1) dietary therapy, 2) exercise, 3) antibiotics, 4) probiotics, 5) anti-diarrheal agents,
6) restoration of normal motility, 7) anti-inflammatory or immunosuppressive therapy, and 8) behavioral modification.
1. Dietary Therapy
The precise immunologic mechanisms of canine and feline IBD have not yet been determined, but a prevailing hypothesis for
the development of IBD is the loss of immunologic tolerance to the normal bacterial flora or food antigens. Accordingly, dietary
modification may prove useful in the management of canine and feline IBD. Several nutritional strategies have been proposed
including novel proteins, hydrolyzed diets, anti-oxidant diets, medium chain triglyceride supplementation, low fat diets,
modifications in the omega-6/omega-3 (ω-6/ω-3) fatty acid ratio, and fiber supplementation. Of these strategies, some evidence-based
medicine has emerged for the use of novel protein, hydrolyzed, and fiber-supplemented diets.
Food sensitivity reactions were suspected or documented in 49% of cats presented because of gastroenterologic problems (with
or without concurrent dermatologic problems) in a prospective study of adverse food reactions in cats. Beef, wheat, and corn
gluten were the primary ingredients responsible for food sensitivity reactions in that study, and most of the cats responded
to the feeding of a chicken- or venison-based selected-protein diet for a minimum of 4 weeks. The authors concluded that adverse
reactions to dietary staples are common in cats with chronic gastrointestinal problems and that they can be successfully managed
by feeded selected-protein diets. Further support for this concept comes from studies in which gastroenterologic or dermatologic
clinical signs were significantly improved by the feeding of novel proteins.
Evidence is accruing that hydrolyzed diets may be useful in the nutritional management of canine IBD. The conceptual basis
of the hydrolyzed diet is that oligopeptides are of insufficient size and structure to induce antigen recognition or presentation.
In one preliminary study, dogs with inflammatory bowel disease showed significant improvement following the feeding of a hydrolyzed
diet although they had failed to respond to the feeding of a novel protein. Clinical improvement could not be solely attributed
to the hydrolyzed nature of the protein source because the test diet had other modified features, i.e., high digestibility,
cornstarch rather than intact grains, medium chain triglycerides, and an altered ratio of ω-6 to ω-3 polyunsaturated fatty
acids. Additional studies will be required to ascertain the efficacy of this nutritional strategy in the management of IBD.
Fiber-supplemented diets may be useful in the management of irritable bowel syndrome (IBS) in the dog. IBS is a poorly defined
syndrome in the dog that may or may not bear resemblance to IBS in humans. Canine IBS has been defined as a chronic large-bowel
type diarrhea without known cause and without evidence of colonic inflammation on colonoscopy or biopsy. Dogs fulfilling these
criteria were successfully managed with soluble fiber (psyllium hydrophilic mucilloid) supplementation of a highly digestible
diet.
