A continuously challenged eco-system

16-06-2015 | | |
A continuously challenged eco-system

Modern animal production is known for its high genetic potential, which is often not achieved due to different and complex challenges during the animal’s lifecycle. One of the critical points is situated at the border of the intestinal tube. The gut is a ?continuously challenged eco-system in need of support.

The gut carries an important responsibility in selecting what can be absorbed and what should remain outside the animal’s body. To put this in the right perspective, it is important to note that the surface of the intestinal tract is 300 times the size of the surface of the skin. At the same time, it should give the similar level of protection against invaders, while being highly permeable to absorb nutrients. Intestinal health pops up as a very popular term for one of the most important but at the same time one of the most complex actions related to animal nutrition.

When the use of Antibiotic Growth Promotors (AGP) gained popularity in 1950, this was considered a Panaceae, a universal remedy to improve (intestinal) health status, performance and economics on the farm. With increasing use of antibiotics in animal nutrition (of which 60-80% is used to treat intestinal disorders), in 1990, both scientist and public opinion opened the debate on increased bacterial resistance against antibiotics and its eventual transfer to humans. This milestone lead to a full ban of AGP since January 2006 and a significant reduction of antibiotic use in animal feed in many EU countries. The Dutch government wants a 70% reduction in antibiotic usage across all livestock in 2015. McDonalds in the US is saying it will only be sourcing chicken raised without known human antibiotics by 2017. Tyson Foods has stopped using all antibiotics in its 35 hatcheries and other large US poultry integrators are following the same trend of getting the chicken industry off antibiotics.

Intestinal microbiota and intestinal barrier

In order to obtain a high intestinal health status, eventually in combination with a reduced use of antibiotics, it is first of all important to understand the intestinal system. The intestinal barrier is composed of different types of cells of which the enterocytes are the most abundant ones. These enterocytes are cells that are “bound” to each other by complex protein structures which are called “tight junctions”. This structure has as major task to close the cell lines and to avoid paracellular passage of bacteria, toxins and other undesired substances from the lumen to the inside of the body. Several stress factors will have a negative impact on the quality of the tight junctions, leading to the syndrome called “leaking gut” which allows big sized molecules such as toxins and aggressive radicals to pass in between, resulting in cell damage, production of “Reactive Oxygen Species” (ROS) and activation of the immune system. The latter is automatically paired to the production of inflammatory cytokines. The neutralisation of these inflammatory components will consume significant amounts of nutrients, which leads to reduced growth and increased feed conversion rates. Although the mode of action of AGP has not yet been fully understood, there is evidence to believe that, besides regulation of the microflora, AGP also plays an important part in reducing the level of inflammatory cytokines, which results in substantial energy saving and improved performance.

The intestinal microbiota is composed of more than 500 different species, which live in direct symbiosis with the host. They provide energy to the intestinal wall, prevent colonisation by pathogenic bacteria and help to maintain the intestinal immune system. It has been demonstrated many times that the status of the immune system is (partly) defined by the presence and the type of microbiota in the intestine. Based on the above, we can conclude that a high status of intestinal health is based on a balanced microflora, strong tight junctions, long, healthy and slender villi and low levels of ROS and inflammatory cytokines.



Feed factors affecting gut health

A wide range of factors associated with diet can negatively affect the delicate balance among the components of the chicken gut and, as a result, affect health status and production performance of birds in commercial poultry operations.

Although there is a wide range of anti-nutritional compounds present in various feed ingredients including cereals, the major group is the non-starch polysaccharides (NSP). Common properties of the different NSP are their resistance to the animal’s digestive enzymes and their tendency to create a viscous environment within the intestinal lumen. NSP decrease digesta passage rate and availability of nutrients, while increased digesta retention time facilitates bacterial colonisation and activity in the small intestine.

The physical form of cereal components of feed may affect the morphological and physiological characteristics of the intestinal tract, although published reports in this area of research are inconsistent. In general, finely ground feed may increase mortality associated with necrotic enteritis compared with coarsely ground feed.

Feedborne toxins can cause enteric disease. Mycotoxins and biogenic amines are among the most common examples of feedborne toxins, but also low levels of other chemical toxic substances like pesticides, PCB’s and dioxins might affect gut health. The presence of mycotoxins in poultry feed has been identified as a widespread cause of economic losses due to impaired health status and reduced performance. Adverse effects on the GI tract are probably the major cause of economic losses resulting from trichothecene mycotoxicoses. Among others, cell proliferation and viability, tight junction quality, endocrine secretions and GALT are negatively affected by the presence of toxic chemical components. A reduced secretion of enzymes and histomorphological changes, in combination with reduced absorptive capacity of the enteric cell will have a direct impact on performance and feed conversion. Finally disturbance of the microflora ecosystem and increased level inflammatory cytokines have been well described as a potential consequence of the presence of certain in feed toxins.

Single molecules have their limits

One can easily understand the complexity of the intestinal system. Many scientist and veterinarians agree that one single non-antibiotic molecule will have its limits in order to control the overall situation. Therefore Lumance proposes a concept and a synergistic approach to ensure a high intestinal health status. Lumance is a complex combining slow release and protection technologies ensuring that acids, medium chain fatty acids, butyrate, essential oils, anti-inflammatory compounds and polyphenols are delivered in a gut active way for a powerful and effective antibacterial control, high quality tight junctions, neutralisation of the produced ROS and tempering of the inflammatory cytokine production.

A trial carried out at the Institute of Animal Rearing Technologies of the Lithuanian University of Health Sciences demonstrated clearly the effect of Lumance on gut health and performance. Six hundred 1-d-old Ross 308 broiler chicks were randomly assigned to 1 of 3 dietary treatments for 5 weeks. The dietary treatments were 1) control diet, 2) diet supplemented with Lumance at the level of 1.5 g/kg of feed, 3) diet supplemented with the same mixture as in 2 treatment, but at a higher amount (2 g/kg of feed). The results of growth performance of broiler chickens are presented in Table 1. During 5 week of the feeding the addition of 1.5 g/kg and 2.0 g/kg Lumance in diets for broiler chickens increased the body weight by 2% and decrease in feed conversion ratio by 4%, compared with control group (P>0.05). Analysis of liveability of broiler chicken showed that compound feed supplemented with different content of Lumance during the period of 35 days had no significant influence on the liveability of broiler chickens (P>0.05).

The results of intestinal histomorphometry measurements of broiler chickens are presented in Table 2. Supplementation at 1.5 g/kg of a mixture of analysed additive in diets for broiler chickens increased the height of duodenum villi by 98 μm, the depth of crypts – 105.8 μm (P<0.05), the height of ileum villi – 597.2 μm (P<0.010), crypt depth – 70.4 μm (P<0.010). The higher amount of dietary supplementation 2g/kg of Lumance increased duodenal crypt depth by 70.2 μm (P<0.05) and an ileal villi height by 181.4 μm (P<0.025).

A synergistic concept

The high genetic potential of todays’ production animals, combined with a clear and inevitable tendency to reduce the use of antibiotics, resulting in an increased risk of enteric problems, is a complex situation to manage. Obviously, a one single molecule approach is not dealing with all aspects of intestinal health management and will never be able to compete with conventional use of antibiotics.

Lumance, being a synergistic concept has shown to be a valid alternative for reduced use of antibiotics. Besides, both in layer, breeder, broiler and turkey diets, Lumance, at 500 g/tonne of feed, have proven to be a valid performance enhancer, even in the absence of an intestinal challenging situation.

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Fabian Brockotter Editor in Chief, Poultry World