Gastrointestinal microbiome depletion modifies behavioral processes without changing body composition

Abstract

In recent times, our knowledge on the gastrointestinal microbiota has considerably improved. Dysfunctions of the gut microbiome have been shown to induce modifications of peripheral and central regulatory processes, ultimately leading to behavioral changes that cause functional deficits in brain functions. Therefore, the first aim of the present study was to generate massive dysbiosis of the gut microbiome and to investigate these effects on behavioral responses in adulthood. To determine the impact of the alterations on the behavior we used adult male Wistar rats. Animals have been divided into two groups – the first one was an antibiotics treated-and the other one was a control group. As antibiotic treatment, rats were given broad spectrum antibiotic mixture for 4 weeks. Substances were dissolved in the animals’ drinking water. Following the intestinal microbiome depletion. Open filed test (OFT) was conducted. Throughout the whole experiment, body weight, food and water consumptions were daily monitored, and faecal samples were collected for later determination of the short chain fatty acid (SCFA) levels. The findings demonstrated significant group-differences such as abnormal behavioral and metabolic phenomena identified among the antibiotic treated animals unraveled in the behavioral test as well as in the short chain fatty acid analyses. Our results reinforce that alterations of the microbiota play important modulating role in the central regulatory processes. However, it is uncertain whether the antibiotic-induced dysbiosis directly triggers the altered behavioral phenomena, or these might have caused the change of body composition which itself could define the behavior. Exploring this question will be our next step to determine how the alterations of microbiome can affect behavioral patterns. We aim to introduce a non-invasive body composition measurement technique to explore this question. This method based on the electrical impedance spectrum analysis. By means of this new four-electrode ultra-low frequency bioimpedance measurement technology, we can carry out high-precision full-body measurements or we could correlate bioimpedance measurement data to various parts of the body if it required. By using the bioimpedance technology, we did not observe significant body composition differences between the two groups. These results confirm our hypothesis that antibiotic-induced dysbiosis directly influences the control of behavioral processes.