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Improving performance despite mycotoxins

In the past, solutions for reducing mycotoxin effects in the animal focused on binding. Nowadays, more sophisticated approaches lead the way, including support of a healthy gut, a well-functioning immune system and detoxification mechanisms.

By Yvonne van der Horst, technical manager, Selko Feed Additives & Anna-Katharina Oudshoorn, researcher, Nutreco R&D

Mycotoxins are inevitable contaminants in food and feed and are a major cause of reduced animal performance all over the world. Over 300 mycotoxins are identified, and this number is steadily increasing. Aflatoxins (AFLA), zearalenone (ZEA), deoxynivalenol (DON), ochratoxin A (OTA), fumonisins (FUM) and T-2 toxin (T2) are the most occurring mycotoxins in feed for monogastric animals such as pigs and poultry. In practice, very often a combination of these mycotoxins is found. Mycotoxin risks are often underestimated, since they may act in an additive or synergistic manner. The use of mycotoxin contaminated raw materials can lead also to unspecific signs like loss in performance and more need for medication. These unspecific signs are caused by the effects mycotoxins have on the immune system, the gut barrier or the oxidative status of the animals. Unfortunately, those signs of mycotoxin contamination are most often not directly recognised as mycotoxin related and can lead to huge economic losses.

Binding of mycotoxins only usually is not sufficient, therefore additional strategies are needed to help animals maintaining a good health status during exposure to mycotoxins. Selko Feed Additives has integrated multiple strategies in the Toxo portfolio to support animals during exposure to a broad spectrum of mycotoxins;

  • Effective binding of mycotoxins;
  • Supporting gut barrier function;
  • Maintaining a healthy immune system; and
  • Support detoxification mechanisms

The aforementioned concept has been successfully tested in a series of in vitro and in vivo studies in pigs and poultry. This review focuses on the positive effects of this concept on growth performance and health status during exposure to mycotoxins. All studies have been executed by the specialised mycotoxin research institute Samitec in Santa Maria, Brazil.

Effective binding
Different in vitro studies by Samitec have shown that smectite clays (or products high in smectites) possess the best ability to tightly and efficiently bind aflatoxins. Consistent values of around 99% for binding aflatoxin B1 by Toxo smectites were found throughout all studies both at low and neutral pH (Figure 1).

These studies also demonstrated that those smectites were equally or more effective in binding aflatoxin B1 compared to other mycotoxin binding products on the market.

Strong gut barrier
The intestinal epithelium has many critical functions. One is the absorption of nutrients, but at the same time it also forms the first protective barrier between the lumen of the gut and the bloodstream of the animal. This way it reduces the absorption of potentially harmful substances. The intestinal barrier is mainly formed by tight junctions. Several scientific studies showed that mycotoxins such as DON and OTA reduce the gut barrier function by removing specific tight junction proteins like claudin-7 and occludin.

A study conducted by Selko Feed Additives showed that supplying feed containing maximum levels of DON, OTA and ZEA, according to EU guidelines to weaned piglets leads to an increase in gene expression of tight junction proteins claudin-7 and occludin in the duodenum (Figure 2). This indicates increased protein production which is hypothesised to be caused by the removal of these proteins from the tight junction complexes by DON and OTA.

The glucose biopolymers in the company's broad spectrum mycotoxin protection approach Toxo-XL significantly reduced the gene expression, which indicates that they reduce tight junction breakdown by the mycotoxins. These results prove that glucose biopolymers in the concept support a stable intestinal barrier with strong tight junctions in the presence of mycotoxins such as DON and OTA.

In vivo results
Recently, multiple in vivo studies have been done in both pigs and poultry to demonstrate the beneficial effects of the four support strategies on animal performance parameters. The studied animals were challenged with aflatoxins only, or a mixture of aflatoxins, fumonisins and T-2 toxin. Consistent and synergistic negative effects of single and multiple mycotoxins on feed intake and animal performance parameters were found. This supports the need for a broad spectrum solution for maintaining a good health status and performance when mycotoxins are present in the feed. In all studies, a control group (no treatment) and a control group with the mycotoxin strategy in the diet was included and no significant differences were found between these two groups. This proves that the positive effects of the strategy found in these studies are the result of the support mechanisms against mycotoxins and not a growth promoting effect.

Supplementation of this broad-spectrum approach in the feed of both poultry and pigs resulted in significantly (P<0.05) better feed intake and final body weight compared to the mycotoxin challenged groups. all studies showed a clear positive dose-response effect on these performance parameters. livers are often enlarged by mycotoxins, through different routes. therefore, relative liver weight can be used as an indicator of mycotoxin presence in the blood. relative liver weight was significantly (p><0.05) higher in the animals fed diets supplemented with mycotoxins compared to diets free of mycotoxins in all studies.  when the broad-spectrum mycotoxin protection strategy was added to the diet in the poultry studies, relative liver weight was significantly lower compared to the mycotoxin groups. in the pig study, the product was able to bring the relative liver weight back to the control level.>

Multiple strategies
Since there is always a high chance of multiple mycotoxins present in the feed of pigs or poultry and it was shown that these mycotoxins have a deleterious effect on animal performance, there is a need for broad spectrum mode of action products. Besides binding, additional strategies are needed to help the animals in maintaining a healthy status during exposure to mycotoxins. The results of the described studies show that with these multiple strategies combined in the Toxo concept, it is possible to maintain optimal health and performance of pigs and poultry and to contribute to increased financial results for meat producers.

[Source: Managing Mycotoxins, 2014]

Yvonne van der Horst & Anna-Katharina Oudshoorn

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