A case of tear stain improvement in dog by a dog food

Abstract

Lacrimation is assumed to commonly cause tear staining in household dogs; a correlation between tear stain and pet diet has been reported. We present a case study of a dog whose symptoms of tear stain were altered with dog food. Tear stains worsened with food A, which was previously shown to worsen tear staining,and improved with food B, also reproducing previous study results. Two possibilities may explain the effect of food on tear stains: food allergies and effect to the intestinal environment. Regarding the former, any food material associated with food allergies in dogs was included in the all test foods. No symptoms of food allergy were observed in the dog during the test period. To compare intestinal environment by changing dog food,the pH and short chain fatty acid concentration in the feces were examined. The fecal pH was more acidic when feeding food B versus food A. The short-chain fatty acid concentration in the feces was higher with food B than with food A, suggesting that the lower fecal pH might be higher short-chain fatty acid concentration. Finally, total IgE concentration in the tears was measured to evaluate for a relationship between intestinal environments and tear stain. The concentration of IgE fluctuated too greatly to establish a relationship with tear staining, and further experiments are necessary.