Behavioral disorders as a determinant of alterations in selected bacterial composition and cortisol level in dogs

The microbial community of the gastrointestinal tract in animals and humans plays one of the key roles in the decomposition of nutrients and maintaining the organisms in homeostasis. Dysbiosis of microbial community in the gastrointestinal tract could be caused by environmental or biological factors and additionally effect on behavior of dogs. The purpose of this study was to evaluate the level of main bacteria in feces from dogs with behavioral disorders and compare dogs without behavioral disorders. Two study groups participated in the experiment: healthy dogs (n=3) and dogs with behavioral disorders (n=7). Fecal samples were collected individually from each individual for a period of 4 weeks (1 sample/week), and then bacterial DNA isolation and real-time PCR were performed for the main bacterial phyla (Firmicutes, Bacteroidetes, Proteobacteria) and families (Lactobacillaceae and Clostridiaceae). Subsequently, analysis of cortisol levels from previously collected fecal samples was performed to determine the level of physiological stress. In addition, behavioral analysis was performed in the ethograms of all individuals. The results obtained showed significantly higher levels of the Firmicutes in dogs from the control group compared to groups with behavioral disorders. In the case of the cortisol test, significant differences in cortisol levels between individuals have been shown.