Microbiota: research in animal nutrition is providing insight into human gut microbes

Microbiota: everyone’s talking about it… but what do we really know about it? While human gut microbiota is new area of research for many – and opening new questions on the links between gut health, mental health and immunity – Dijon-based scientific teams have been working on animal microbiota since the 1950s and 60s.

Today, scientific knowledge on animal gut microbiota is allowing researchers to accelerate learning on human gut health. Samy Julliand, director of Lab To Field, a R&D company specialising in animal health and nutrition in Dijon, and Claude Faivre, COO of Wamine, the animal health unit of the Pileje group, share their insights. 

Gut microbiota: what are we talking about?

Microbiota, “to be understood as a plural”, explains Samy Julliand, director of Lab To Field, are microbial communities that live in niche habitats. “For each niche, there is a specific ecosystem of microbes, bringing together bacteria, fungi, protozoa, viruses etc. There are many niches on the human body: the mouth, the small intestine, the bowel, on the skin, in the lungs etc.,” he explains.

The role of these microbiota is today recognised as essential to a number of functions, thanks to the ongoing interactions between microbes and the host body: for digestion (digestive bacteria help to degrade substrata that are inaccessible to the enzymes produced by our bodies), but also for immunity, metabolism, cognition, mental or physical performance, sleep quality etc. “The list of systems impacted by the microorganisms that we all live with is immense,” says Samy Julliand. 

Keeping things in balance – in humans and animals

Samy Julliand, who works mainly on gastroenterology, explains further: “Intestinal microbial communities are not only there to digest certain energy-rich compounds, as is commonly thought. In fact, they are constantly interacting with the host. When we modify the species present in our small intestine or our bowel, (through lifestyle changes, stress, fatigue, medications or dietary changes), we cause structural changes in the microorganisms present and in the interactions with the host body. This can lead, for example, to an inflammatory response.” This is the topic of a doctoral thesis carried out by a member of the Lab To Field team that was defended in December 2021.

To sum up, when your microbiota is altered, many things can start to malfunction: digestive troubles, but also immunity, chronic inflammatory diseases, schizophrenia, sleep disorders, or anxiety. Without knowing the exact biological links, recent research also suggests that pathologies such as Alzheimer’s can be correlated to changes in gut microbiota. “We use the term ‘dysbiosis’,” explains Claude Faivre, COO of Wamine, the animal health unit of the Pileje group. And dysbiosis is characterised by its impact on the overall health of the subject, whether animal or human. “In the case of dysbiosis we need to rebalance the microbiota using a probiotic supplement, with certain families of commensal bacteria, in order to reduce inflammation and to allow the subject to regain their normal balance in their microbiota.”

Samy Julliand goes further: “At Lab to Field, we are studying the modulation factors of microbiota, such as diet, and the consequences on the efficiency of digestion, on health or on behaviour. For example, our research has highlighted that unbalanced gut ecosystems in animals can have inflammatory effects not only on a local level, but also on a systemic level. This is why we are working on solutions in animals that can address and limit gut dysbiosis.”

“While many studies are needed to understand the links between microbiota dysbiosis and these pathologies, current experiments on animals have shown that an improvement in certain diseases, even systemic ones, is possible by modifying gut flora,” adds Claude Faivre. “This is what we set out to prove with a research program conducted with Lab To Field: how probiotics given to horses suffering from gut stress did not help them to better digest fodder – but DID help to regulate the microbial populations in their gut, which limited the negative impact of stress from diet or medications. The probiotics thus played a “peace-keeping” role regarding the immune system, by helping to put the digestive mechanisms back in order.”

Animal microbiota: a long history of scientific research…

Research into animal gut microbiota has indeed a long head start on human gut microbiota. “This is because of the vital importance of gut health for herbivores,” explains Samy Julliand.  Unlike humans (who are omnivores who get their nutrients from varied sources), herbivores can only feed on cellulose and hemicellulose fibres that make up plant cells, that are degraded by microbes in their rumen or bowel, according to the species. Here are a few numbers: while a human being can get 10-15% of their energy from degraded plant fibres thanks to our fibrolytic (fibre-consuming) microbiota, in herbivores this represents nearly all their energy sources. In some species of herbivores, the least disturbance in their microbiota, in particular in fibrolytic, so-called “keystone”, strains, can have serious consequences on their nutrition, and thus on their health.

“In the field of cattle farming or horse breeding, in order to maintain herbivorous species such as dairy cows or race horses in good health or even to improve their performance, we have been asking the same question since the 1960s: how can we preserve or encourage the growth of beneficial microorganisms in animals?”

Claude Faivre adds that “since the 1950s and 60s, there have been a number of studies into yeasts and bacteria. Researchers noticed that calves who drank milk directly from the udder or milk fermented in a bucket, two non-sterile food sources, had fewer incidences of diarrhoea than other calves. The benefits of fermented bacteria for gut balance were suspected thanks to this observation.”

“In addition, since lactobacilli increased the synthesis of short chain fatty acids, used in the production of sugars, and thus in fat and meat, improving a hundred or so categories of gut microorganisms in farm animals was an efficient means of improving their zootechnical performance,” he adds.

… leading to improvements in the understanding of human gut microbiota

Many studies on herbivore gut microbiota have been carried out in Dijon since the 190s.

“One of the leading teams studying herbivore digestion was created in Dijon in the 1960s,” adds Samy Julliand. “The analytical techniques and understanding have progressively improved and today we have a wide-ranging knowledge of animal gut microbiota. This has allowed us to study the structure and diversity of bacterial communities, their predicted or real functions, etc. As we now have the chance to carry out studies in controlled conditions, we can work on the causal link between modifications to digestive microorganisms and the consequences on digestion, health and behaviour.”

While Claude Faivre focuses exclusively on farm animal and domestic pet models, he is fascinated by the new areas of exploration opening up in human health and nutrition. “If we study strains present in the digestive tract of a family with a household pet, we can observe that there is a genuine exchange between the human microbiota of the family and that of the pet… a phenomenon that has been ascribed as the cause of the stronger immune system found in children benefitting from direct contact with animals.”

From his side, Samy Julliand is confident that knowledge sharing is possible between research into animal or human models. “Regarding the pathogenesis of certain diseases, the animal species that we have studied can be very relevant for understanding the origin of problems in humans. Today, several projects are we are leading are conjointly studying humans and animals.  Building bridges between knowledge of humans and animals is indeed one of the goals of the last scientific conference that we organised in November 2021.”

To address future challenges, Lab to Field is currently strengthening its team in order to undertake further studies of the relationships between diet, gut microbiota and health of human beings… as one of the many species of mammals. 

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To find out more about Lab to Field, feel free to contact me: Maria Isabel Cisneros, maria-isabel.cisneros@vitagora.com.

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