Effects of Lactiplantibacillus plantarum PS128 on alleviating canine aggression and separation anxiety

Abstract

Certain strains of Lactiplantibacillus were found to have a positive impact on host neuromodulation through the gut-brain axis and thus ameliorate emotional and behavioral problems. A number of researches have been performed on humans, mice and rats; however, studies on dogs are limited. Forty-five dogs with behavioral problems were enrolled in this study, including aggression (n = 22), separation anxiety (n = 15), compulsive disorder (n = 7) and unclassifiable inappropriate behavior (n = 1, excessive barking). The behavioral diagnosis was made based on the primary behavioral consultation questionnaires and the careful interrogations at interviews. Lactiplantibacillus plantarum PS128 (PS128) probiotic was administered to these physically healthy dogs with behavioral problems over a course of two weeks to determine the probiotic effectiveness on canine behaviors. Dogs were evaluated and scored using the Evaluation of Dog’s Emotional and cognitive Disorders (EDED) scale and the Canine Behavioral Checklist (CBC) questionnaire at the visits before and after the probiotic treatment. Plasma serotonin levels were measured using high-performance liquid chromatography- electrochemical detection (HPLC-ECD) and the serotonin turnover ratios (5-HIAA/5-HT) were compared pre- and post-treatment. The results showed that the general behavioral stability was improved, and the problems of aggression and separation anxiety were ameliorated after treatment. A significant decrease in 5-HIAA/5-HT ratio was observed in dogs with separation anxiety, suggesting a serotonin-related mechanism. These results proved that PS128 was beneficial for emotional stabilization, which might be useful as a therapeutic supplement for canine aggression and separation anxiety.