Today's Veterinary Practice

MAY-JUN 2018

Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.

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Page 19 of 87

PEER REVIEWED 18 NUTRITION NOTES from 6 months of age up to 12 years of age. In one study, one-third of food allergic cats were Siamese or Siamese crosses. Symptoms and lesions may include pruritus without lesions, miliary dermatitis, head/neck/ear pruritus, scaling, eosinophilic granuloma complex lesions, or self-induced alopecia. Lymphadenopathy may be present in 30% of cats and 30% of cats may have accompanying flea allergy or atopy. Gastrointestinal problems can occur in up to 50% of food allergic cats with bowel biopsies yielding lymphoplasmacytic +/- eosinophilic inflammation. Studies in cats show that beef, dairy, and fish are the most common food allergens but wheat, egg, chicken, soy, and dairy should also be avoided when choosing a hypoallergenic diet as well as any previously fed protein. The problem in cats is getting them to eat a new diet. FOOD ALLERGY MYTHS Grain free is not hypoallergenic. It is also not necessarily low in carbohydrates as other carbohydrates such as pea, potato, and tapioca may be higher in calories with weight gain as a result. Another misnomer is that meat by-products are "bad." Meat by-products, which include the heart, lungs, liver, and stomach all have more essential nutrients than skeletal muscle meat. "Human grade" is a designation used by Honest Kitchen, as in 2007 they sued the State of Ohio to use the term as a matter of free speech. It wasn't until August, 2016 that AAFCO defined "human grade" and set standards for the use of this term. The term may only be used in reference to the product as a whole, not if only one ingredient is human grade. Documentation that each and every ingredient is human grade and the facility manufacturing conforms to human grade food standards including shipping to qualify. The term cannot be given undue emphasis on the package label or be larger than "statement of use." HEART DISEASE (DCM) IN GOLDEN RETRIEVERS FED GRAIN-FREE DIETS Taurine is an amino acid needed for normal development/function of heart, eyes, muscle. Taurine deficiency is a cause of DCM.2 If the owner wants to feed a grain-free diet it would be prudent to measure taurine levels before and after starting the diet. Taurine deficiency can also be seen in lamb-based diets as lamb meat does not hold taurine well, and it gets excreted in the feces. FOOD ALLERGY— MECHANISM OF ACTION In patients with enhanced gastrointestinal (GI) permeability, food allergy may perpetuate inflammatory bowel disease (IBD) yet not be the primary cause of IBD. A normal mucosal barrier and normal IgA levels, which are the body's first step in recognition and elimination of foreign antigens needs to be present. Digestion results in protein breakdown to free amino acids and small peptides, which are poor antigens. Poor digestion results in large polypeptides and residual antigenic proteins that are highly reactive in the gut and activate the immune system. Protein hydrolysates of <10,000 Daltons are less likely to elicit an allergic response. Food allergy is suspected to involve Type I, II, III, IV, and V reactions, which is one of the reasons serum testing for food allergy is not valid! Food additives are often blamed for allergies, yet there is little data to support this. SELECTING A HYPOALLERGENIC DIET AS A DIAGNOSTIC FOR FOOD ALLERGY A thorough diet history must be asked of the owner inquiring which proteins the pet has been exposed to previously. With the advent of over-the-counter "limited ingredient diets," our protein selections are dwindling. One study found that 4 over-the-counter "limited ingredient" venison diets also contained soy, poultry, and beef that were in the diet yet not listed on the label.3 A follow-up study evaluated "no soy" diets yet 3 out of 4 diets were positive for soy antigen. Use a prescription hypoallergenic diet or home- cooked diet with either a single novel protein or protein hydrolysate as a test for food allergy. Manufacturers of prescription hypoallergenic diets test their final product for other proteins that over-the-counter food manufacturers do not. Another study of a prescription hydrolyzed chicken diet revealed that there was potential for up to 50% of chicken allergic dogs to react to that protein hydrolysate diet.4 Another chicken based hydrolyzed diet did not show chicken cross reactivity but possible reaction to the cornstarch contained in the diet where dogs were corn sensitive.5 Serum or skin testing for food allergy in the dog and cat has yet to be proven valid. A study revealed serum testing for food showed 80% negative correlation vs. only 20% positive correlation. 6

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