Whenever animal welfare and well-being is in focus, the term “gut health” comes up as well. But what defines gut health and how can it be maintained? Surely there is more to gut health than merely the absence of gastrointestinal illness. Good digestion and absorption of nutrients are as much a sign of a healthy gut as an effective immune system and a normal and stable microbiota. There is no doubt that animal nutrition plays an important role in maintaining the integrity of the gut. The search for advanced dietary strategies to strengthen the resilience of animals to infections and non-infectious stressors is therefore a powerful driver for the development of innovative feed additives aimed at improving gut health and animal well-being.
The microbiota – a closer look
Many of the challenges we encounter in animal production can be related to poor gut health. Dysbiosis in poultry it is often associated with poorly digested feed, diarrhoea, and wet litter, leading to footpad dermatitis, reduced uniformity of the flock and ultimately to losses in productivity. Poor eggshell quality may also be linked to gut health problems, especially in older hens which rely on an effective calcium absorption for eggshell formation. In piglets, post-weaning diarrhoea caused by uncontrolled proliferation of E. coli is a threat to both animal welfare and production profitability.
Numerous studies describe the positive effects of a healthy and balanced gut microbiota and its metabolites on innate and adaptive immunity, metabolism, gut physiology and even animal behaviour. Stress factors such as early weaning, heat stress or diet composition may lead to a disruption of the intestinal barrier and impair the animals’ resilience. Only a healthy gut with a balanced microbiota can function as a barrier between the environment and the animal and provide protection from pathogens. It is therefore important to improve and maintain this barrier function of the healthy gut to prevent harmful or toxic substances from being absorbed into the body from the environment.
How to support a healthy gut
A key factor for regular intestinal biology are short chain fatty acids like acetic, propionic, and butyric acid. They are the product of bacterial fermentation in the intestine. A high concentration of short chain fatty acids lowers intestinal pH which in turn suppresses pathogen bacteria and facilitates mineral absorption. Butyric acid improves the epithelial integrity and defence systems and decreases intestinal permeability. To optimise the effect of butyric acid in the gut, it must reach the target site. Different forms of butyric acid, either supplemented or endogenous, will have different effects in the animal, dependent on the digestive compartment they reach. Butyric acid in the stomach has an antibacterial effect and improves protein digestion. In the distal part of the intestine, it will strengthen the epithelial barrier, reduce inflammatory processes, and stimulate the production of antimicrobial peptides.
Nutrition impacts intestinal health
In other words, the more butyric acid in the hindgut, the better. How can this be achieved? Free short chain fatty acids are rapidly digested in the stomach or the crop. Supplemented butyrate must therefore be specially protected so that it reaches the distal parts of the intestine. This may be done by encapsulating the butyrate, for instance with fatty acids. However, release of the butyric acid throughout the gut needs to be well-timed and may not be optimal.
A better way to maximise butyric acid concentration in the hind gut is to stimulate the endogenous production of butyrate in the lower part of the intestine. The strategy is to make substrates – known as prebiotics – available to specific micro-organisms, generating conversion products essential for the growth of the digestive system. Prebiotics are generally carbohydrates like fructo-oligosaccharides. They provide a useful energy source for beneficial bacteria. A different approach is the use of gluconic acid, which is structurally related to sorbitol, a slowly fermentable sugar. It is not or hardly absorbed in the small intestine of monogastric animals. Due to the microbial fermentation of gluconic acid, lactate and acetate originate as by-products. These are then converted to butyric acid by acid-utilising bacteria in the large intestine and the caecum.
PreAcid – it’s all in the blend
There is a solution especially developed to improve growth and the continuous self-renewal of the intestinal mucosa. PreAcid, a multifunctional feed supplement for highperformance animal feed, contains short-chain fatty acids and the GlucoFence complex which consists of a combination of gluconate and butyrate.
What effect does PreAcid have in the intestine? The organic acids in PreAcid inhibit pathogens and so prevent diarrhoea – still top of the list of common diseases. The prebiotic components butyrate and gluconate promote intestinal development. This has been proven in several trials, where for instance an increased production of butyric and total acids and the improvement of microflora composition in the caecum of broilers could be observed (figure 2a and b). Also, PreAcid reduced the concentration of E. coli lipopolysaccharides in the blood serum of broilers challenged with E. coli and Salmonella (figure 2c). The detection of LPS in the serum in that study suggests that the negative effects of E. Coli and Salmonella on the intestinal barrier of broilers could be mitigated by the prebiotic action of the GlucoFence complex in PreAcid.
Lower mortality and higher final weight
The benefit: PreAcid is the ideal source of butyrate in animal nutrition, improving performance and productivity. In a large-scale trial with broilers comparing the effect of PreAcid with butyric acid, the PreAcid concept clearly outperformed other sources of butyric acid. The animals were allocated to two groups. The control group received fat coated butyric acid, the treatment group received PreAcid. After eight fattening rounds the result for the PreAcid group was definitive: the animals reached higher final weights and a better feed conversion ratio. The mortality was reduced by up to 24 per cent (figure 3). Furthermore, the use of PreAcid reduced feed costs per kg meat by 2.8 per cent and markedly increased meat yield.
Strong gut – strong performance
Optimising the amount of butyric acid in the hind gut will benefit both animals and producers: the antibacterial and prebiotic action improves gut health, stimulates digestion, and improves nutrient absorption and animal welfare. So for a healthy gut and optimal performance in poultry, go for the full effect of butyric acid in the intestinal tract. PreAcid’s prebiotic approach with the GlucoFence will get you there.
Article contributed by Dr. Elisabeth Holl, Senior Technical Manager & Dr. Bernhard Eckel, Vice President, Dr. Eckel Animal Nutrition, Germany
