Optimizing gut function is key to poultry health. Probiotics and butyrate have been used in poultry nutrition for many years and understanding is growing on their beneficial actions. In this way their precise formulation and where they are delivered in the gut has been perfected. This strategy helps producers control pathogens like Salmonella, Campylobacter and Clostridium perfringens – as well as reducing reliance on antibiotics.

Gut health

The gut mucosa is the location of interactions between the host, the microbiota and external elements. It is also where absorption of nutrients and stimulation of the innate immune system takes place, along with preventing bacteria and toxins entering the bloodstream. The intestinal integrity of poultry is constantly challenged by the environment, diet and pathogens. The development and maintenance of a robust gut function depends on the composition of the gut microbiota. If the gut and the microbiota is supported, so is the health of the bird.

Modes of action

Probiotics are used as feed additives to create a healthy and resilient microbiota. Bacillus subtilis DSM 29784 (Bs29784), has been shown to be effective in protecting animals. It does this by acting on three connected lines of defence: ensuring a resilient microbiome, strengthening the gut barrier function and preserving gut integrity – as well as maintaining a reactive immune system. Probiotic solutions for poultry should be specifically designed to deliver consistency, along with optimal germination and activity in the intestine.

There is a wealth of data on the benefits of butyrate on gut health in many species. Butyrate is a central signalling molecule, which has a direct effect on the microbiota, which benefits intestinal integrity. Production of caecal butyrate only starts around 12 days of age in broilers. In poultry kept under standard conditions, the use of a precisely delivered butyrate in starter diets improved gut morphology, including villi surface area. Under challenging conditions, the differences were even more marked.

The next level

The efficacy of butyrate depends on how it is supplemented, and the formulation of the additive used. Butyrate is able to activate several physiological responses along the entire digestive tract: as several gut-associated cell types will recognize butyrate as signaling molecule or use it as energy source. To ensure this, a precise formulation that protects the product and controls release is required. Different butyrate products were compared in broilers infected with Salmonella (Figure 1). The higher the level of sustained release protection, the higher the amount of relative butyrate concentration in the caeca. Which most importantly was correlated with reduced Salmonella counts in the caecum.

To help poultry deal with constant challenges, probiotics should be fed throughout the life of the bird. In this way the immune system is supported, preventing the negative health effects of pathogens and issues such as heat stress. The microbiota determines what happens in the gut lumen and surroundings. Bs29784 produces metabolites, which in turn influence the microbiota – reducing the numbers of competitor microorganisms (Figure 2).

Synergy

To promote good health throughout the cycle a good start is essential. Feeding butyrate supports gut development to help the bird prepare for challenges. Bs29784 added to all diets provides backup protection whatever happens. The immature gut of the young bird takes a while to be able to effectively combat challenges. By feeding a probiotic it helps the bird develop a beneficial microbiota faster, which will in turn produce butyrate. However, the fastest way to get to an optimal level is to feed a superior form of butyrate.

Reducing contamination of poultry products by Salmonella and Campylobacter, is a priority for governments and retailers alike. Figure 3 shows the different points that Salmonella can infect poultry and ways that dietary intervention can protect them. Butyrate is anti-inflammatory and helps to protect the integrity of the gut, reducing translocation of pathogens. Bs29784 has a unique profile of metabolites that increase its activity, including niacin, a vitamin acting as an enzymatic co-factor. Studies have shown that it shares a receptor in the gut with butyrate. Together Bs29784 and butyrate create an environment that is much less favourable for pathogen colonisation.

Resilience throughout the cycle

It is important to understand the situation of individual producers in order to create an optimal gut health programme. There will be differences in consumer priorities, environmental and market conditions. Using additives that empower the gut throughout, and throughout the bird’s life – supports poultry health and profitable production. Working together on complementary beneficial pathways within the gut, probiotics and butyrate support gut health. Resilience from the start and throughout life results in a bird that is more able to deal with stresses no matter when they occur.

Authors:

Damien Prévéraud, PhD and Tim Goossens, PhD: Global Scientific & Technical Manager – Health by Nutrition, Adisseo. damien.preveraud@adisseo.com and tim.goossens@adisseo.com