- Begin nutritional support only when the patient is warm, alert, and hydrated.
- The bird with gastrointestinal disease should initially be fed a high-energy, low-fiber diet that contains an easily digestible protein source.
- Offer dietary fat judiciously due to the relatively complex digestive process required.
- Look for a diet that contains glutamine: the preferred source of energy and nitrogen for small intestinal mucosal cells.
The gastrointestinal tract acquires and digests food, absorbs nutrients and water, and expels unabsorbed ingesta as feces. Nutritional support of the avian patient with gastrointestinal (GI) disease is challenging. In cats and dogs, it is easy to “rest” the gut, however with their relatively high metabolic rate, this is difficult, if not impossible, to achieve in many avian patients. Specific disease conditions increase the difficulty regulating gastrointestinal motility including ingluvitis or inflammation of the crop. Crop stasis, a common presenting complaint with many avian patients, is a gastrointestinal disease associated with delayed crop emptying and regurgitation.
Basic approach to the gastrointestinal patient
The initial clinical approach to the bird with gastrointestinal disease should be to provide supplemental heat and fluids as supportive care. If the patient is extremely weak, a few drops of 50% dextrose or corn syrup (i.e. Karo syrup, ACH Food Co.) administered orally, may benefit the overall condition of the animal.
Once the patient is warm and rehydrated, gavage feed small amounts of a liquid diet as long as the patient can maintain an upright posture and is alert. If an excessive amount of fluid is introduced into the intestines, this may induce “dumping syndrome” which may result in diarrhea, and vomiting.
Liquid diets come in two basic formulations, elemental and polymeric. Elemental diets generally contain readily available nutrients such as glucose, amino acids, and fatty acids. Lafeber Emeraid Omnivore™ and Emeraid Carnivore™ are examples of semi-elemental diets. Polymeric liquid diets, including hand-feeding formulas or Abbott Clinicare®, are made of intact nutrients, and usually considered a balanced and complete nutritional product.
Dietary recommendations for gastrointestinal diseases
As a general rule of thumb, the bird with gastrointestinal disease is initially fed a high-energy, low-fiber diet that contains an easily digestible protein source such as Emeraid Intensive Care Omnivore™. If a carnivore must be fed, offer a liquid diet such as Emeraid Intensive Care Carnivore™ or muscle meat as opposed to whole prey, which includes components, which are difficult to digest such as fascia or connective tissue.
- Carbohydrates are present in the diet as simple sugars, disaccharides and polysaccharides. Their primary role is to serve as a readily available source of energy.
- Ideally, the diet should contain the amino acid, glutamine. Glutamine is the preferred source of energy and nitrogen for small intestinal mucosal cells. Epithelial cell renewal requires a great deal of energy.
- Offer dietary fat cautiously since fat digestion is a complex process easily disrupted in gastrointestinal disease. Medium-chain triglycerides may be a good substitute for fat because they do not require micelle formation for absorption and they are readily absorbed in the stomach and proximal small intestine.
- Although the amount of normal dietary fiber varies widely among avian species, with most cases, a low fiber diet should initially be fed. Dietary fiber may assist in the management of bacterial overgrowth, inflammatory bowel disease, pancreatitis, and colitis. Fiber promotes gastrointestinal motility and provides nutrition to colonic epithelial cells. Colonic epithelial cells use butyrate, a short-chain fatty acid produced by bacterial fermentation within the cecum for energy. Avian species with a developed cecum include chickens and other gallinaceous birds and waterfowl. Ceca are absent or vestigial in psittacine birds and passerine species.
- Supplement various vitamins and minerals for patients with maldigestion and malabsorption (i.e. proventricular dilatation disease or PDD). The antioxidant vitamin E has been specifically recommended for patients diagnosed with PDD (0.06 mg/kg IM q7d or 15 mg/kg PO once).
- Although there is no empirical data to support there use, there are commercially available diets labeled for gastrointestinal disease such as Roudybush Rice Diet®, Roudybush AI Intestinal Care®, and Roudybush APD Proventricular®.
- Parenteral nutrition may be indicated for birds suffering with severe intestinal disease.
Probiotics have been recommended for prevention and treatment of infectious diarrhea as well as prevention of antibiotic-induced diarrhea. Probiotic use does not appear to hurt the patient, however data on its use in non-domestic bird species like the parrot is equivocal. Other than improving the intestinal environment to stimulate the growth of normal flora and inoculation of desired bacteria, data in chickens and humans suggests that some probiotics exert a beneficial effect by modulating mucosal barrier function and immune activity. Research also suggests that a combination of probiotics may be more effective than a single strain. Products that provide avian specific bacteria in their product are thought to be more effective when compared to other probiotic supplements. Multibacterial probiotics containing organisms such as Lactobacillus spp., Bifidobacterium spp., Enterococcus spp., and Pediococcus spp. are available.