L. Coblentz’s research while affiliated with Unity Health System and other places

Fourteen dogs with known clinical hypersensitivity to soy and corn were maintained on a limited antigen duck and rice diet until cutaneous manifestations of pruritus were minimal (78 days). Sequential oral challenges with cornstarch, corn and soy were then performed. Subsequently, the dogs were fed a diet containing hydrolysed soy protein and cornstarch. Throughout the study period the dogs were examined for cutaneous manifestations of pruritus and, additionally, serum was collected for measurement of allergen-specific and total immunoglobulin (Ig)E concentrations. Intradermal testing with food antigens was performed prior to entry into the study and after 83 days. A statistically significant clinical improvement was measured between days 0 and 83. Significant pruritus was induced after oral challenge with cornstarch, corn and soy (P = 0.04, 0.002, 0.01, respectively) but not with the hydrolysed diet (P = 0.5). The positive predictive value of the skin test for soy and corn allergy was reduced after feeding a soy and corn free diet. Although increases in soy and corn-specific serum IgE concentrations were measured in individual dogs post challenge they were not statistically significant and could not be used to predict clinical hypersensitivity.

Hydrolysate diets have been advocated in the management of the food-allergic dog, but little information is available on their performance in dogs with known allergies. Fourteen dogs with known allergies to soy and corn were maintained on a limited antigen diet exclusively for 80 days (Hills d/d Rice and Duck, Hills Pet Nutrition, Topeka, KS). This diet was continued during oral challenge with 200 mg kg−1of cornstarch, corn and soy respectively on two occasions each at 24-h intervals. There was a minimum period of 15 days between each challenge. A diet containing hydrolysed soy protein and cornstarch (CNM HA, Ralston Purina Co., St. Louis, MO) was then introduced. Before and after each oral challenge the dogs were examined and a clinical score was determined; serum was also collected for measurement of allergen-specific and total IgE concentrations. Statistical analysis employed the use of a longitudinal mixed model and was performed using SAS software (Cary, NC). Significant increases in clinical scores were seen after oral challenge with cornstarch, corn and soy (P = 0.04, 0.002, 0.01 respectively) but not with HA (P = 0.5), although three dogs did develop clinical signs after this latter challenge. Allergen challenge did not affect total serum IgE concentrations. Although increases in soy- and corn-specific serum IgE were measured in individual dogs post-challenge they were not statistically significant, and could not be used to predict clinical hypersensitivity. This study was funded by a grant from Ralston Purina Co., St. Louis, MO.