Optimising fibre formulations for poultry gut health

By Xaviere Rousseau - AB Vista Global Poultry Technical Manager

The strong connection between animal gut health and productivity cannot be denied. Poor gut health can lead to less nutrient absorption, energy losses, gut integrity damage and dysbiosis; in turn, having negative economic implications for producers. The challenge lies in the fact that the wider sector is reducing its reliance on antibiotics – meaning an alternative approach is needed.

The interrelationship between gut health, nutrition and microbiota has encouraged the development of nutritional strategies that have been shown to help optimise poultry gut microbiome. Consequently, this can have a positive impact on nutrient digestion, absorption, metabolism and overall health and growth performance.

Digestion and the microbiome

Why is digestion so important? Efficient digestion aims to provide absorbable nutrients required by the animal that can transit to the metabolic part and play their specific role. To achieve this, and to make the feed more valuable for the animal, there is a need to ensure a proper balance between nutrients and/or reduce the undigested fraction. One strategy is to limit the undigested protein arriving in the distal part of the gut, while including specific fermentable fibre that can benefit gut integrity and function.

Fibre as a functional ingredient

Due to the shift away from antibiotic growth promoters (AGP), alternative nutritional strategies are being widely examined, scrutinising different substantial and functional aspects of nutrition.

It is known that fibre plays a pivotal role in nutrition. However, its optimal level depends on the animal’s age and the compartment of the gut. Fibre type, content and ratio to undigestible protein is also crucial to keep carbohydrate fermentation going through the distal gut, while avoiding harmful bacteria and toxic compounds production.

How do we define fibre today? Chemically, fibre refers to all non-starch polysaccharides (NSPs) plus lignin, which consists of macromolecular polymers of monosaccharides joined by a specific type of linkage called a glycosidic bond.

Physiologically, dietary fibre is the edible parts of plants or analogous carbohydrates (polysaccharides, oligosaccharides, lignin, and associated plant substances) that are resistant to digestion and absorption in the small intestine and undergo complete or partial fermentation by microbes in the large intestine (AACC, 2001).

We usually distinguish soluble and insoluble NSPs, and evaluating these fractions helps us to understand or predict their physiological effects within the animal and optimise their use in feed formulation. While analysing fibre via wet chemistry methods is time consuming and expensive, AB Vista’s NIR (Near Infra-Red) Spectroscopy Service can rapidly determine the NSPs within cereals and protein feed ingredients. With a calibrations database of more than 400,000 global reference samples and over four million spectra, the NIR Service provides producers with reliable, real-time data that enables producers to predict fibre content different of feed ingredients and optimise diet formulation.

Determining fibre content and characteristics can therefore support producers in reducing the anti-nutritional effects that some of these components have, as well as provide an appropriate substrate for the beneficial bacteria to ferment.

The role of feed additives

To achieve a healthy gut, it is imperative to establish a stable, functional microbiome with a level and type of fermentation beneficial to the animal. A balanced microbiome is obtained when carbohydrate fermentation predominates over protein fermentation, as the former produces volatile fatty acids (VFAs), such as acetic, propionic, and butyric acid, which have a positive effect on gut health and the overall metabolism of the animal.

There are a variety of feed additives available as an alternative to AGPs to stimulate and maintain a healthy gut. These include prebiotics, probiotics, organic acids, phytobiotics/essential oils, enzymes, and stimbiotics – which all vary widely in their nature and mode of action.

Stimulating the establishment of a fibrolytic microbiome producing VFAs will deliver a multitude of benefits, including lowering hindgut pH levels, providing energy to maintain the enterocytes, modulating the mucosal immunity, and preventing pathogen attachment. This is the idea behind the stimbiotic concept, developed and introduced by AB Vista.

Stimbiotics

Stimbiotics, such as Signis, have been demonstrated to favourably stimulate the microbiota fermentative capacity, providing multiple benefits on different levels.

Acting on dietary fibre, stimbiotic supplementation can provide performance gains at the same time as improving gut health and animal resilience to the different challenges they may face in regular commercial production. The stimbiotic becomes a multifunctional tool, which combines the benefits of different feed additive categories. For example, broiler chickens under an induced necrotic enteritis challenge that received a stimbiotic with their diet, were as resilient to challenges to gut integrity, inflammatory response and growth performance as birds fed a combination of prebiotic, probiotic, and essential oils (Figure 1).

Figure 1. Effect of a stimbiotic alone (Signis) or in combination with prebiotic, probiotic, essential oil, and yeast mannan (Signis+) compared to a control diet without any additive (control) in induced necrotic enteritis challenge (challenge) or not (no) on [TNF-alpha] as a marker of the inflammatory response and [Endotoxins] as a marker of gut integrity

Conclusion

The role of dietary fibre in achieving optimal gut function appears even more significant than initially thought. Exploring the new opportunities that fibre may offer in monogastric nutrition is key to gaining a better understanding of the beneficial bacteria that ferment fibre.

Using stimbiotics and functional feed additives that target the fibrolytic microbiome – and being equipped with efficient tools to analyse fibre in the diet – can afford producers a multitude of benefits including gut resilience, improved liveability and increased growth rate.

Discover more about AB Vista’s work in poultry nutrition at IPPE 2024, Jan 30-Feb 1, Atlanta, Georgia, USA. Alexandre Barbosa de Brito, PhD, AB Vista Feed Additives LATAM Technical Manager, will be presenting a TECHTalk on ‘Utilizing Dietary Fibre for Optimal Performance’ on 1 February, 10:30a.m at Hall A, Booth A244. AB Vista will also be holding two presentations on 29 Jan, at the joint event International Poultry Scientific Forum: ‘Feed fibre profile and the use of stimbiotic influence broilers productivity and hindgut fermentation’, by Xaviere Rousseau, and ‘Reduction of mortality in broiler chickens as a result of feeding a stimbiotic’, by Gemma Gonzales Ortiz.

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