Anxiolytic effects of administration of a commercially available prebiotic blend of galacto-oligosaccharides and beta glucans in Sprague-Dawley rats

Abstract

Prebiotics are nondigestible food agents that stimulate the growth of bacteria in the gut, whereas probiotics are live microorganisms that replace or restore beneficial bacteria in the digestive tract. Both agents have been shown to have beneficial qualities within the microbiota-gut-brain axis, but the behavioural effects of prebiotics have been less studied than probiotics. Whereas several studies have shown that prebiotics reduce inflammation and modulate anxiety in animals that are injected with lipopolysacccharides or chronically stressed animals, respectively, it is not yet known how they affect a healthy organism. Here, we tested the behavioural effects of galacto-oligosaccharides and beta glucan as a commercially available prebiotic blend in healthy, naïve Sprague-Dawley rats. We used the open field test and elevated plus maze to assess anxiety-like behaviour in controls and in rats that ingested the prebiotic blend in their drinking water. We also used the Morris Water Maze to assess spatial memory performance in controls and prebiotic treated rats. Rats treated with prebiotics spent more time in the intermediate zone of the open field test and in the open arms of the elevated plus maze, and exhibited a shorter latency to enter each of these zones. No significant differences between groups were found in the Morris Water Maze. Our results suggest that whereas prebiotics significantly reduced anxiety-like behaviours, it had no effect on spatial memory performance. Altogether, our data indicate that commercially available prebiotic beta glucan blends have anxiolytic effects in healthy rats.