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ToDay's VeTeriNary PracTice | November/December 2015 | tvpjournal.com acVN NuTriTioN NoTes Peer reviewed 74 • Many practitioners try to reduce BuN in renal disease patients, but if this is done by severe protein restriction (< 20 g/1000 kcal), protein malnutrition may result, causing increased morbidity or mortality. 25 Hepatic Encephalopathy Protein modifcation is required in the subset of liver disease patients with liver failure characterized by hyperammonemia and hepatic encephalopathy (He). • Liver failure is best assessed by a combination of direct (ammonia, bile acids) and indirect (albumin, cholesterol, BuN, bilirubin, and glucose) function tests; elevated liver enzymes alone do not warrant protein restriction. • a reduction in urea cycle activity is responsible for He; the nitrogen liberated from normal protein processing is not converted to the less toxic by-product, urea. Protein restriction to about 40 g/1000 kcal has been suggested for He. 4 Feeding increased branched chain amino acids with decreased aromatic amino acids has also been suggested for He, but past studies in dogs did not support this intervention. 33 Vegetable-based protein may reduce the signs of He, possibly due to increased small intestinal digestibility and reduced bacterial fermentation in the colon, which reduces the bacterial contribution to blood ammonia levels. 4 Food Allergies Food allergy should be distinguished from food intolerance. a true allergy generally occurs to a specifc protein or proteins present within the diet, and both meat and plant proteins have been reported to cause hypersensitivity. • No evidence exists that protein restriction reduces allergic signs. if protein is restricted in a diet formulated for diet trials, it is likely because of the cost of the protein or hydrolysate used. • Novel protein diets should not be antigenic, but cross-reactivity is possible and contamination of some limited ingredient diets has been reported. 34 • Hydrolyzed diets contain proteins, usually poultry or soy, exposed to a chemical process to disrupt their structure and antigenicity. The molecular weight of the resulting fragments may correlate to antigenicity, and such diets are used for food allergies and chronic enteropathies. 35 IN SUMMARY Pet diets should be carefully evaluated for adequacy of amino acids. Fortunately, most commercial diets following aaFco standards exceed the needs for most dogs and cats, making defciency unlikely. Home-prepared diets, however, should be evaluated closely for adequacy. Taurine defciency is the most notable clinical presentation in protein- defcient animals. The protein content of foods should also be carefully assessed on a caloric basis when diets are evaluated for weight loss, performance, aging, chronic renal disease, He, and some forms of urolithiasis. a detailed analysis of amino acid requirements may be required in complex conditions or in animals that consume lower amounts of food than expected. aaFco = association of american Feed control offcials; BuN = blood urea nitrogen; GFr = glomerular fltration rate; He = hepatic encephalopathy; kcal = kilocalories References 1. aaFco. 2015 aaFco Offcial Publication. champaign, iL: aaFco, 2015. 2. National research council. Nutrient Requirements of Dogs and Cats. Washington, Dc: The National academies Press, 2006. 3. sanderson sL. Taurine and carnitine in canine cardiomyopathy. Vet Clin North Am Small Anim Pract 2006; 36(6):1325-1343. 4. Proot s, Biourge V, Teske e, rothuizen J. soy protein isolate versus meat-based low-protein diet for dogs with congenital portosystemic shunts. J Vet Intern Med 2009; 23(4):794-800. 5. Johnson ML, Parsons cM, Fahey Gc Jr, et al. effects of species raw material source, ash content, and processing temperature on amino acid digestibility of animal by-product meals by cecectomized roosters and ileally cannulated dogs. J Anim Sci 1998; 76(4):1112-1122. 6. Brown ca, Jeong Ks, Poppenga rH, et al. outbreaks of renal TAble 3. Phosphorus Content of s elected Protein s ources Found in Home-Prepared Diets P rotein so U r C e PH os PH orUs (g/100 grams protein) Whole Egg 1.5 Tofu 1.4 Salmon fllet 1.2 Cottage cheese 1.1 Ground venison 0.9 Top sirloin beef 0.8 Skinless chicken/ turkey breast 0.7 Egg whites 0.1 Specifc nutritional recommendations for renal disease will be discussed in greater detail in an upcoming issue of Today's Veterinary Practice.