Feed additives

Background

Optimising gastrointestinal functionality

Recently, the term gut health has acquired increasing importance in animal nutrition and more focus of scientific developments and modern feeding strategies. From a scientific perspective, however, there is still no consensus on how to operationalise the factor of gut health.

A whole series of positive functions of the gastrointestinal tract are associated with gut health, see Figure 1. An effective digestive function and the absorption of nutrients, the absence of gastrointestinal diseases, a high immune status, well-being of the animals and a stable, healthy gut flora is closely linked to gut health. However, maintaining gut health is a very complex subject and based on a delicate balance between nutrient intake, symbiotic microflora and the mucosa with superimposed digestive epithelium. The composition and quality of the feed is of particular importance for gut health. These influencing factors can be valuable or harmful to gut health. For this reason, a targeted and well-balanced composition of food and nutrients is of essential importance. Only by maintaining and stabilising the balance of the digestive system at all times, can it be ensured that the multifaceted functions of the intestine are not impaired. Against this background, the microbial life – or in other words, the microbiome of the intestine – is gaining a vital importance for gut health.

Figure 1 – Major points for a healthy gastrointestinal system.

The significance of the microbiome

The intestinal microbiome is a complex community of widely diverse microbes. Bacteria, which are by far the largest group of the microbial community, support or adopt a wide range of functions such as the digestion of fibres or nutrients, the regulation of epithelial functions, release of anti-microbial peptides, regulation of the tight junction function, protection against pathogen colonisation or regulation of the mucosal immune system. Particularly the protection against the colonisation of pathogens is key to maintaining gut health. Any negative impact on the gut flora, e.g. by oral administration of antibiotics or an unbalanced nutrient intake results in a reduced functionality and immune power of the gut. Therefore, the maintenance of this complex and sensitive ecosystem is the basis for keeping the largest immune system of the body active and in effective working order.

In order to promote and enhance the gastrointestinal microbiota, special feed additives such as probiotics, prebiotics and organic fatty acids or essential oils are becoming increasingly important in animal feeding. The growing group of functional additives offers many still unexplored approaches to positively influence gut health. Considering the possible positive and negative interactions, this partly unexplored segment becomes even more extensive. Medium-chain fatty acids are highly effective additives for the promotion of gut health and have therefore found their place in the feed industry.

Photo: iStock
Photo: iStock

Antibacterial effect of MCFA’s

Medium-chain fatty acids (MCFA’s) are saturated fatty acids with a carbon chain length between 6 to 12 carbon atoms. They are mainly found as medium-chain triglycerides in substantial quantities in the milk fat of some species and in some plant-based feeds such as coconut and palm kernel oil. Specifically, these are caproic acid C6, caprylic acid C8, capric acid C10 and lauric acid C12. The strong antibacterial and antiviral effect of medium-chain fatty acids has been proven in many scientific studies. The level of the MCFAs’ activity, however, depends on many influencing factors. Particularly the pure medium-chain fatty acids have a few negative properties, which limit their effectiveness and possible uses. Due to the MCFAs’ correlation with the degree of dissociation, the pH value of the application environment is of prominent significance for the particular application. In vitro studies clearly demonstrate that the efficacy of MCFAs decreases with increasing pH value. In addition, the corrosive MCFAs have intense and negative olfactory and gustatory characteristics, which limit the application quantities particularly with young animals. In their natural form, MCFAs occur as triglycerides, i.e. esterified with glycerin. These medium-chain triglycerides (MCT) are an excellent and readily available source of energy. MCTs are mainly used in the feeding of young stock and provide a valuable source of energy, which exceeds the calorific value of dextrose many times over. In vitro studies do not associate MCTs with having a direct antibacterial effect. In the course of the digestive process, however, MCFAs and so-called medium chain monoglycerides (MCMs, i.e. monoglycerides of medium-chain fatty acids) are released. This decomposition process is induced by specific lipases, the activity of which varies according to the species. Poultry for example entirely lack lipases. The most effective and powerful form of MCFAs by far is gained by esterifying a single, medium-chain fatty acid with glycerin to form a monoglyceride. It is of central importance for the efficacy of monoglycerides from medium-chain fatty acids, that the medium-chain fatty acid and glycerin are covalently linked at the 1-alpha position, the only antimicrobial form of MCM. Another decisive advantage of MCMs is that their mode of action is independent of the pH value. The MCMs’ active form does not depend on the pH value of the environment, which enables them to exhibit their activity in the entire gastrointestinal tract. Due to the esterification with glycerin, the medium-chain fatty acids lose their corrosiveness as well as the negative smell and taste. The handling and possible uses of MCMs is greatly improved and effective application quantities can easily be realised even for young stock.

Photo: iStock
Photo: iStock

MCFA/MCM mode of action

The mode of action of MCFAs/MCMs is based on various approaches, with the destabilisation of membranes by introduction into the cell wall and the cytoplasmic membrane of the harmful bacteria being the main effect mechanism. In this process, the medium-chain fatty acids attack and destroy the bacterial outer membrane. This bactericidal effect could be demonstrated for various bacteria with different cell wall structures – both for gram-negative and gram-positive bacteria. Other explanations for the MCFAs/MCMs mode of action are the reduction of the intracellular pH value due to dissociation of the absorbed fatty acids in the cytoplasm of the bacteria, the prevention of bacterial colonisation on the intestinal wall by inhibiting bacterial lipases and by influencing autolytic enzymes of the bacterial cell wall, which induce bacterial cell death. In addition to their antibacterial effect, in particular MCMs exhibit a high level of antiviral activity against lipid coated viruses. In some cases this already occurs at a concentration that is ten times lower than in MCFAs. Recent studies also attribute good anti-inflammatory effects to MCMs.

For the successful maintenance and promotion of gut health, high-quality MCM solutions are important. Berg + Schmidt has placed the focus of its research and development on the evolution of high-quality MCM solutions. LipoVital GL-90 is the result of a specific molecular esterification, with a 1-alpha-monolaurate content of more than 90%. This highly complex esterification process produces a powdery monolaurate, which requires no carrier substance, thus ensuring the highest degree of purity and active agent concentration. Due to the omission of a carrier substance, the availability of monolaurate is significantly optimised and even low quantities of LipoVital GL-90 ensure the positive effects on gut health. The combination with other monoglycerides such as caprylic acid, capric acid or butyric acid from the LipoVital toolbox allows the use of synergistic effects and to configure bacteria-specific solutions.

References available on request

Author: Christian Cordts, Product Manager Feed Additives, Berg + Schmidt