Perturbations to the gut microbiome (by antibiotics, infection, stress, etc.) are capable of disrupting the gut bacterial community leading to a state of dysbiosis. Small intestinal bacterial overgrowth (SIBO), characterized by excessive density of resident bacteria in the small intestine, is a common example of dysbiosis. Pathogenic bacteria in the gut induce anxiety-like behaviour and stress, accelerating completion of learning maze performance. However, it is not known whether an overgrowth of resident bacteria such as that seen in SIBO would have the same effect. A diet containing raw red kidney bean (RRKB) is capable of inducing SIBO. The aim of this study was to test the hypothesis that SIBO induced by an RRKB-supplemented diet might accelerate completion of learning maze performance during radial 8-arm maze testing. Twelve mice were tested in a radial 8-arm maze while on either standard rodent chow (Control group) or an RRKB-supplemented rodent chow (RRKB group) for 24 hrs. To test for bacterial overgrowth, DNA was extracted from small intestinal tissues, qPCR was performed, and universal 16S rRNA data was transformed into fold change compared to the Control group using the 2 -ΔΔ Ct method. The RRKB group had 37.4+/-12.1 fold higher bacterial density in the mid-small intestine than control mice (P<0.05). The maze run time was shorter for RRKB group (124.8+/-28.7 s) than Controls (251.8+/-72.8 s) (P<0.05). The RRKB group had less time spent in arms (97.5+/-53.5 s) than Controls group (212.2+/-53.8 s) (P<0.01). A diet of rodent chow supplemented with raw red kidney beans accelerated the completion of radial 8-arm maze test. This observed behaviour change may be an acute effect on the host by the overgrowth of resident bacteria in the small intestine.
