Journal of Bacteriology & Parasitology

The effect of Mycobacterium vaccae on ultrasonic vocalizations of male mice during anxiety-provoking situations

2^nd International Congress on Bacteriology & Infectious Diseases

November 17-19, 2014 DoubleTree by Hilton Hotel Chicago-North Shore, USA

Matthews D M, Jenks S M, Hillers K and Blase K

Posters: J Bacteriol Parasitol

Abstract:

Although inaudible to humans, male mice frequently communicate with each other by emitting ultrasonic vocalizations (USV). The frequencies at which they emit these USVs are indicative of their emotional state. Research shows that mice will vocalize between 18-32 kHz in aversive situations. Mycobacterium vaccae, a non pathogen found in temperate soils has been shown to stimulate the serotonergic system of the mouse brain. This is most likely due to activation of an immune pathway that stimulates serotonin production. It was hypothesized here that mice that ingested with M. vaccae would emit a different USV pattern than control mice that were not fed M. vaccae. Twenty male BALB/c pathogen free mice were used for testing. Each mouse was treated daily for 7.5 weeks, and then tested for five minutes in a Zero Maze (EZM). The EZM maze is designed to invoke fear and anxiety in mice. USVs were captured using a Binary Acoustic AR 125 Ultrasonic receiver, and then analyzed using SCAN?R software. Results show that while eight out of ten of the untreated mice demonstrated USVs within the range 20-40 kHz, only three out of ten of the M. vaccae treated mice demonstrated USVs within the range 20-40 kHz (χ?=(1, N=20)=5.1, p<0.05). This suggests a positive effect of M. vaccae on the fear state of male BALB/c mice.