With varying though complementary backgrounds ranging from neuroscience to gastroenterology to animal behavior, all shared a common interest in probiotic research and application.

The meeting focused on the intricate and complex relationship between the brain and the gut. New and exciting data were shared, contributing to establishing the interactions between this “brain-gut“ axis and the gut microflora, as well as the potential of probiotic use.

At a time when modern farming practices represent an important source of stress factors for animals, affecting their performance, health and well-being, some promising behavioral studies were shared showing that probiotics can help to manage stress and influence behavior. This unique interdisciplinary meeting was a real platform for exchanging ideas and methodology. It allowed the participants to set new directions for future probiotic research and paved the way for new applications in both animal and human nutrition.

The brain, the gut and the bugs: a fascinating triangle

The idea of a brain–gut axis is not a new concept, the first scientific studies of the subject date back to the 1960s. The fact that communication works both ways and that the gut can talk to the brain is a more recent concept. Even more novel is the idea of looking at the role of the intestinal microflora, or microbiota, with the addition of probiotics, in this brain-gut cross-talk.

As explained by Professor Stephen Collins of McMaster University Medical Centre (Canada): “The intestinal microbiota has profound effects on host function and should be incorporated into a modern conceptualization of the gut-brain axis.“ He added: “In this model, changes in brain responses, such as stress or anxiety, influence the physiology of the gut, altering the habitat for the microbiota. The microbiota, in turn, influences gut physiology and immunity at the gut mucosa level. Our recent data indicate that perturbation of the microbiota also influences behavior..“

Until now, probiotics had mostly been documented for their role in digestive health and functions: prevention of diarrhea or bloating, transit regulation, lactose intolerance…in human, and optimized feed efficiency and pathogen control in animal production. In recent years, scientists have also studied their interactions with the immune system. With their action on the gut microflora balance, probiotics could also affect the brain-gut axis, as confirmed during the seminar.

Effects of probiotics on behavior, stress and anxiety

More than ten different scientific studies were presented, showing how specific probiotic preparations play a role in animal behavior, their reaction to stress, anxiety, or memory formation post-infection.

For animals raised with modern production methods, stress is a recurrent issue, and probiotics are increasingly used as a natural solution to control pathogens development or to optimize performance. Several significant studies were presented showing how probiotics can also impact stress and behavior and be an ally to reduce the impact of stress in animal production.

During the session dedicated to monogastric animals, for instance, Dr Nicola Walker (Lallemand, Montreal), demonstrated that farrowing, an important stress event for sows and yet an extremely critical step of its production cycle, induced a dramatic change in the sows digestive microflora. She explained that:“ In our study, we showed that the normal balance of the sow’s gut microflora was disturbed by farrowing. However, when the sows had received probiotic yeast Saccharomyces boulardii I-1079 for three weeks prior to farrowing, their microflora was less affected by this stress event, indicating a degree of stabilization.“ She concluded that: “The probiotic yeast may help to stabilize the gut normal microflora during periods of stress, thus potentially reducing the proliferation of opportunistic pathogens and thereby leading to improved health and performance.“ In another presentation by Dr Alex Bach, from IRTA, Barcelona (Spain), it was re-stated that ruminant-specific yeast S. cerevisiae I-1077 can help regularize feeding patterns in dairy cows.

Didier Desor, Professor of Behavioural and Cognitive Neurosciences at University Henri Poincaré in Nancy (France), presented a pre-clinical study with a probiotic preparation (Probio’Stick™ from Institut Rosell-Lallemand) which has already been shown to be effective in humans in reducing the gastro-intestinal symptoms linked to stress. Using a mouse model validated with Diazepam, it was shown that: “the probiotic was able to reduce signs of anxiety, displaying an “anxiolytic-like“ effect. Such effect had not been previously described with probiotics.“

All probiotics are different

One of the evident conclusions that came from the numerous discussions during the seminar was the renewed certitude that all strains are different. The benefits exerted by a particular microbial strain or blend of strains cannot be extended to others. Some of the studies presented were conducted on different probiotic preparations and the outcomes were diverging. We are just beginning to comprehend the necessity of matching a probiotic with a state of health.

Looking to the future

During the round-table discussion, it came out loud and clear that experts from different disciplines in both human and animal health have a lot to learn from each other. Professor Phil Sherman, from the Hospital for Sick Children, University of Toronto (Canada), who chaired the discussion, concluded that: “the seminar was a great opportunity to build bridges, not only between the industry and academia but also between the different disciplines.“ We are learning that nutrition, gut health and psychological health need, more and more, to be linked together. All the participants left with new ideas and concepts which will be exchanged through new collaborations and interactions.