19 November 2018 – Prior to the XVth European Poultry Conference (EPC) organized by the World’s Poultry Science Association (WPSA) in Dubrovnik, Adisseo hosted its Advancia Academy in the Croatian city. Animated by ten worldwide experts, the day-long event focused on intestinal frontier integrity and what that means in terms of animal performance.

“We decided to focus our 3rd Advancia Academy on understanding the drivers of intestinal frontier integrity to support performance efficacy,” said Dr. Pierre-André Geraert, Director Scientific Marketing, Adisseo. “The intestinal wall is indeed the last digestive frontier before the blood.”

The intestinal wall has to face a dual function: absorbing nutrients and avoiding entrance of unfavorable bacteria and dietary components. “It is thus more a frontier than a barrier,” also commented Dr. Geraert.

Feedinfo News Service was able to catch up Dr. Geraert to get a better understanding of the main topics of discussion in Dubrovnik.

Dr. Pierre-André Geraert
Director – Scientific Marketing

“Gut integrity is a hard topic for nutritionists but challenging for animal performance. It has to be taken into account for more adequate feed formulation,” he said. “What are the solutions to strengthen gut immunity and how to evaluate gut integrity were some of the key questions the experts tried to answer.”

Prof. Todd Applegate from University of Georgia (USA), kicked off the day by stating that the gut has to be considered as a highly dynamic system ready to adapt to ingredient matrix and bacterial environment. But he warned that these responses can alter endogenous maintenance as well as nutrient and energy digestibility. The gut response to pathogens depends on their amount, their virulence and of predisposing factors (e.g. cocci, mucin type, etc.). Gut immunological responses may vary nutrient “needs” with changes in tissue maintenance needs and nutrient use efficiencies.

The digestive tract also absorbs anti-nutrients such as phytate and has its part to play on the function of the intestinal wall. Prof. Markus Rodehutscord from the University of Hohenheim (Germany) pointed out that indigestible components and anti-nutrients can interfere with the global nutrient digestibility.

“He explained that phytate can indeed be significantly degraded in the intestine but the dietary level of minerals such as Ca and P drastically affects this degradation. It is thus important to adequately monitor minerals, avoiding excess, to guarantee efficacy of endogenous and exogenous, mucosal and bacterial, phytase activities,” commented Dr. Geraert.

Prof. Mike Kidd of the University of Arkansas (USA) looked at the role of amino acids in the functioning of intestine, whereby the first pass of amino acids supplies the intestinal amino acid requirement. Challenging conditions (e.g. dirty environment or sub-clinical Clostridium infection) therefore significantly increase the demand for lots of amino acids including threonine and branched-chain amino acids. Arginine needs also increase under coccidiosis challenge.

Prof. Kidd also confirmed: “All these elements need to be taken into account when formulating the dietary amino acid supply. And we should also not forget the difference in amino acid requirements between males and females.”

There is also the issue of tight junctions and the importance of avoiding paracellular absorption while favoring the transcellular one. According to Dr. Raquel Martin-Venegas of the University of Barcelona (Spain), dietary solutions, such as OH-Met, pro- and prebiotics can meet this challenge by strengthening the tight junctions and thus the intestinal frontier. In that light, Dr. Estelle Devillard from Adisseo (France) showed the potential of a Bacillus subtilis and how it can help at each level of digestive health (microbiota, mucosal barrier, immune tolerance, redox system).

“Probiotics can act at the four levels involved in digestive health. Their effects are strain specific. The mechanisms involved are under investigation, but at least involves the production of bioactive compounds,” said Dr. Geraert, echoing Dr. Devillard’s comments made during the Advancia Academy.

Dr. Geraert added: “Probiotics, prebiotics, management of the indigestible fraction as well as the anti-nutrients are part of the solution. But we should not forget that we are dealing with a complete ecosystem which shows the importance of the interactions between host and microbiota as illustrated by Prof. Bernd Kaspers from Munich University (Germany) showing the importance of the microbiota in the development of the immune system.”

Prof. Bernd Kaspers also pointed out that the gut immune system is the largest immune tissue in the body and is the first to have to deal with pathogens and other ingested xenobiotics. And with the use of germ-free, SPF (specific pathogen-free) and conventional microbiota models, the importance of a large microbiota, diverse and well-developed, for the development of an efficient immune reaction avoiding inflammation response was clearly demonstrated.

Another challenge for the intestinal frontier described to the Advancia Academy audience was parasites. INRA’s Dr. Fabrice Laurent (France) explained that an optimal microbiota may help to resist the parasite challenge.

“He argued that innate immunity is important, particularly for neonates and young animals, in controlling pathogens in the intestine, and sees immuno-stimulation of innate immunity as a promising strategy for controlling parasite development,” added Dr. Geraert.

Finally, when addressing microbiota, we often do not distinguish between the luminal and mucosa-associated bacteria. Prof Filip Van Immerseel of Ghent University (Belgium) demonstrated the importance of the mucosa-associated population for gut health and that butyrate-producing bacteria seems essential.

Further commenting on these remarks, Dr. Geraert said: “Feeding strategies can steer towards butyrogenic (mucosa-associated) taxa in the gut. Butyrate, even from dietary origin, seems to have potency to reduce effect of pathogens in the intestine.”

The gut is also continuously facing oxidative challenge and as Prof. Peter Surai of Feed-Food Ltd. (UK) said, maintaining the optimal balance between pro-oxidant and anti-oxidant compounds is also important to guarantee gut efficacy. Prof. Surai sees selenium-based anti-oxidants as efficacious in protecting the gut from oxidation.

Investigating on the intestinal frontier integrity has been a research axis developed by Adisseo over recent years with its OH-Met, OH-SeMet and Bacillus subtilis-based probiotic. The company also says its Feedase concept demonstrated that a range of enzyme activities is able to change the substrates for the gut microbiota favoring the butyrate producers and thus a more beneficial microbiota. In April 2019, Adisseo will also organize an Advancia Academy, prior to the IHSIG conference in Roma, focusing on “Butyrate: from a nutrient to a messenger” showing its large potential from endogenous stimulation to exogenous complementation.

“A nutritionist cannot anymore deal only with raw materials and their digestibility. He has to consider the animal as a complete ecosystem and has also to take into account challenges faced by the animals when formulating diets to support optimal performance,” said Dr Geraert.

Videos of all presentations are available on www.feedchannel.online with the highlights, the complete presentations as well as the questions raised by the participants and the answers from all speakers.