The gut microbiota plays a crucial role in the bi-directional gut–brain axis, a communication that integrates the gut and central nervous system (CNS) activities. Animal studies reveal that gut bacteria influence behaviour, Brain-Derived Neurotrophic Factor (BDNF) levels and serotonin metabolism. In the present study, we report for the first time an analysis of the microbiota–gut–brain axis in zebrafish (Danio rerio). After 28 days of dietary administration with the probiotic Lactobacillus rhamnosus IMC 501, we found differences in shoaling behaviour, brain expression levels of bdnf and of genes involved in serotonin signalling/metabolism between control and treated zebrafish group. In addition, in microbiota we found a significant increase of Firmicutes and a trending reduction of Proteobacteria. This study demonstrates that selected microbes can be used to modulate endogenous neuroactive molecules in zebrafish.

Background: Animal-assisted intervention (AAIs) represent an adequate expression of integrated medicine, according to the One Health approach. We argue that AAIs are interventions based on interspecific relationships between humans and animals. Although there are many studies on the effects of AAIs on animal and human health and wellbeing, research is still needed to give us more data. For example, information is still lacking on the aspects characterizing and influencing the interspecific relationships occurring in AAIs. The efficacy of an intervention based on interspecific relationships will be influenced by different factors, such as attachment styles and personalities of both the animal and the handler, an appropriate choice of animal species and their individuality, animal educational training techniques, the relationship between the handler and the animal, and relational reciprocity between animal, the patients, and members of the working team. Method: This article aims to contribute to the study of interspecific relationships in AAIs via theoretical considerations. An interspecific relationship determines the result of safe interventions, which directly influences the welfare of the animal. Results and considerations: AAIs should be evaluated systemically as a network within a process in which every component interacts with and influences other components. Standardized methods using appropriate tests and parameters are needed to better select appropriate animals (i.e., species and individual subjects) using interspecific relational competences as well as appropriate educational training methods and health protocols to assess potential risks.

Animal-assisted interventions are widely implemented in different contexts worldwide. Particularly, animal-assisted therapies and animal-assisted activities are often implemented in hospitals, rehabilitation centers, and other health facilities. These interventions bring several benefits to patients but can also expose them to the risk of infection with potentially zoonotic agents. The dog is the main animal species involved used in these interventions. Therefore, we aimed at collecting data regarding the occurrence of the pathogens ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) in dogs, in order to draft guidelines concerning the possible monitoring of dogs involved in animal-assisted therapies and animal-assisted activities in healthcare facilities. We performed a literature search using the PRISMA guidelines to examine three databases: PubMed, Web of Science, and Scopus. Out of 2604 records found, 52 papers were identified as eligible for inclusion in the review/meta-analysis. Sixteen papers reported data on E. faecium; 16 on S. aureus; nine on K. pneumoniae; four on A. baumannii; eight on P. aeruginosa; and six on Enterobacter spp. This work will contribute to increased awareness to the potential zoonotic risks posed by the involvement of dogs in animal-assisted therapies, and animal-assisted activities in healthcare facilities.