Dietary Intervention Alleviates Signs of Atopic Dermatitis in Dogs by Improving Gut, Skin and Systemic Immunity

Abstract

ObjectivesAtopic dermatitis (AD) is a common skin disorder in dogs. We hypothesize that dietary intervention alleviates AD by improving gut, skin, systemic immunity and skin health. MethodsControl food (CF) and Test food (TF) were formulated to meet or exceed AAFCO nutritional recommendations. Both foods had similar macronutrient levels (fat: 16.2% ±1.2, protein: 17.2% ±0.9, carbohydrate: 52.9% ±0.9, crude fiber: 1.1% ±0.05, total dietary fiber: 5.0% ±0.1, moisture: 8.1% ±0.9 and ash: 4.2% ±0.2) except for the ratios of soluble:insoluble fiber (S/IF) and linolenic (C18:3):arachidonic fatty acids (C20:4) (C18:3/C20:4). The ratios of S/IF and C18:3/C20:4 are: in CF 0.04 and 10.1 and in TF 0.27 and 26.6 respectively. 14 Derm disorder dogs (DD, n = 14) and pair-matched 16 healthy dogs (HD, n = 16) were pre-fed a maintenance food for 28 days and then randomized into 2 groups based on their age, gender and disease condition followed by a cross-over design without a washout period and each phase was fed for 42 days. Fecal and blood samples were collected for all dogs and assessment of skin symptoms was conducted by a veterinarian for DD dogs. ResultsThere was an improvement in the response rate of reduced pruritus, erythema, alopecia, skin and ear secretion severity in DD by 53.8%, 46.1%, 7.6% and 38.4% respectively, when fed TF compared with CF. Mean level of fecal calprotectin and alpha 1-proteinase were decreased in DD and HD dogs when fed TF (11.8 ng/g & 18.0 μg/g) compared with CF (25.0 ng/g & 20.1 μg/g), with ±Sp 30.2 & 14.6, respectively. Similarly, mean level of serum IgE and cholesterol were decreased in DD and HD dogs when fed TF (48.8 μg/ml & 199.2 mg/dL) compared with CF (61.5 μg/ml & 226.5 mg/dL), with ±Sp 63.0 & 44.9, respectively. Metabolomic analyses revealed that TF decreased circulating acylcarnitines, but increased long chain PUFAs and NAD metabolic pathway intermediates compared with CF which indicating an anti-inflammatory, antioxidant and improvement in skin barrier function respectively. TF also decreased circulating short chain sphingomyelins and ceramides to improve skin lipid homeostasis. ConclusionsTF intervention alleviates AD via multifaceted approach by improving gut, skin and systemic immunity and skin health in dogs. Funding SourcesThis study was funded by Hill’s Pet Nutrition, Inc.