Better gut health prevents antibiotic resistance
As 70% of the immune system capacity of the birds is concentrated around or inside the gut, it is therefore easily understood that a good intestinal integrity will have a positive impact on the bird's immune status, reducing the need for antibiotics and hence the problem of antibiotic resistance Over the past decades, genetic selection has enabled the poultry sector to achieve heavier broilers at the slaughterhouse (2.8 kg at 42 days in 2013 vs. 1.7 kg in 1960). Birds have been selected for their capacity to grow, but also for a higher feed intake. At the same time, antibiotic growth promoters have been banned in Europe and are put into question in other regions of the world. Meat and bone meal is also less and less used.
This evolution has had some consequences : even minor violations of the digestion and the absorption (subclinical coccidiosis, cold or heat stress, drinking water quality, feed quality, etc…) increase the quantity of nutrients available for opportunistic bacteria present in the gut ( Clostridium, E.coli, …). This can lead to the development of bacterial enteritis and/or to necrotic enteritis.
Figure 1 shows the evolution of an enteritis is a sort of vicious circle where each cause has an impact on the gut morphology and microbiology, which induces itself another step in the vicious circle. If nothing is done, this will lead to an uncontrolled disorder, triggering eventually a necrotic enteritis.
Figure 1: The vicious circle of enteritis in broilers.
Which measures have to be taken?
Good farm management including drinking water quality, ventilation, a high level of biosecurity and high feed quality (presentation, feed transition and composition) are essential to prevent physiological disorders and to make the birds more resistant. Phase 1 of the vicious circle.
Alternatives to antibiotics are playing a growing role, and one reliable solution is the incorporation of the prebiotic Safmannan® into the poultry feed. Safmannan® is the premium yeast parietal fraction, manufactured by Phileo Lesaffre Animal Care, and coming from the fermentation of a proprietary yeast strain ( Saccharomyces cerevisiae ), selected for its beneficial features on the gut health and the immune system of the birds. The fully controlled manufacturing process enables to get a consistent product in its balanced composition in mannans and β-glucans, and in its effect on the birds. Broilers and layers are very high productive animals today. A good gut health is important to enable the best efficiency of the feed. As 70% of the immune system capacity of the birds is concentrated around or inside the gut (Gut associated lymphoid tissue (GALT), peyer patches, spleen, liver, fabricius bursa), it is therefore easily understood that a good intestinal integrity will have a positive impact on the bird's immune status.
Several points have to be respected to maintain a good gut health:
- Keep the absorption capacity of the gut: importance of the villi length. Phases 3 and 4 of the vicious circle
Several trials have demonstrated the effect of Safmannan® in the preservation of the villi length in challenging conditions (Clostridium challenge for instance), and thus maintaining an optimal absorption of the feed nutrients (see graph 1). By controlling the release of certain pro-inflammatory cytokines, Safmannan® enables to attenuate the effect of the intestinal inflammation, and thus preserves the villi length. Another effect is less deep crypts and a higher ratio villi length/crypt depth, which is a good parameter to measure for the gut health evaluation.
Graph 1: Safmannan® helps to maintain villi length in challenging condition
Protect the gut cell wall from pathogen attacks: goblet cells number and mucus layer. Phase 2 and 3 of the vicious circle
A trial has shown the effect of Safmannan® on the number of goblet cells, secreting the mucus which will protect the gut cell wall. Birds fed with a Safmannan® supplemented feed presented 3 times more goblets cells than those fed with a control feed (see graph 2 and pictures 1 & 2)
Graph 2: Safmannan® helps to increase the number of goblets cells and the thickness of mucus layer. (Morales et al. , 2010)
Pictures 1 & 2: Effect of Safmannan® on the number of goblet cells. (Morales et al ., 2010)
- Decrease the pathogen pressure in the gut: E.coli, Salmonella, Clostridium. Phase 2 of the vicious circle
Gram- bacteria have the ability to attach to the gut cell wall with specific antigens, the Fimbriae. These antigens bind to mannans covering the surface of the intestinal epithelium. As Safmannan® contains at least 20% of mannans, these bacteria bind preferably to Safmannan® , when put together in contact inside the gut (see pictures 3 & 4). When Donaldson et al. used Safmannan® to demonstrate this mechanism, 98% of the Salmonella Typhimurium strain tested was bound by Safmannan® , and 62% of Clostridium perfringens. This last bacteria is indeed a Gram+ bacteria with no Fimbriae. The mode of action for Gram+ bacteria is still to be elucidated but the fact remains that Safmannan® helps to decrease pathogen bacteria pressure in the gut and helps to limit their bad effects on gut health.
Pictures 3 & 4: Safmannan® binds pathogen bacteria like E.coli and Salmonella (Donaldson et al ., 2014) (MEB pictures x6500)
Oxydative stress is also an important disorder occurring during an enteritis. Phase 3 of the vicious circle
Selsaf® , the selenium enriched yeast, also manufactured by Phileo Lesaffre Animal Care, and providing a natural dual source of selenomethionine and selenocysteine. This second amino-acid is a direct component of the Gluthation peroxidase, one of the most important antioxidant enzyme. Thus, Selsaf® helps to control the negative impact of the oxidative stress.
There is no universal solution to warranty a good health for the broilers and the layers. Depending on the circumstances, modifications in the farm management and a good observation of the birds will help to limit the predisposing factors and the different stress which can occur during a production period. As certain safeguards are put into questions, like antibiotics, Safmannan ® and Selsaf ® can be good alternatives to help the birds to grow in an optimal way.
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Article made possible through the contribution of Phileo