The importance of evaluating the efficacy of a mycotoxin binder to fight mycotoxicosis
Global prevalence of mycotoxins
Mycotoxins are toxins produced by fungi that, once ingested by animals, cause considerable secondary effects, such as a worsening of performance and serious economic losses. In addition, they can reach humans whether directly (through contaminated food) or indirectly (through the intake of animal products).
They can be found worldwide, mainly in broken or low-quality grain with high humidity. Furthermore, some studies point out that approximately 50% of the contaminated grain has one mycotoxin, while the 45% contains 2 and the last 5% contains 3 or more fungi toxins. This is important because mycotoxins act synergistically, which means they increase the toxicity of other mycotoxins.
For all these reasons, mycotoxins control are of great interest for food safety and animal production.
Addition of a binder in the diet
Nowadays, food safety is of major importance worldwide, so that there is an increasing interest to control feed and food contamination by fungal toxins (mycotoxins).
The addition of mycotoxin binders in feed has been proved to be an effective method to avoid these negative effects. The target of these products is to bind mycotoxins and avoid their absorbance in the animal gastrointestinal tract.
Mycotoxin binders can be distinguished according to their base molecule (glucomannans -yeasts-, enzymes and silica polymers) and by their efficacy to bind mycotoxins.
Evaluation of a mycotoxin binder
In vitro evaluation
A good method to evaluate a mycotoxin binder in vitro should consider the following:
- GI tract conditions of monogastric and polygastric animals: the physicochemical conditions vary along the digestive tract and can affect the binder’s efficacy.
- Mycotoxins can be detached throughout the GI tract: the method should evaluate the efficacy of the binder at the end of the tract, not only in the stomach.
- The method must allow the evaluation of the binder’s efficacy against different mycotoxins.
Biovet S.A. has patented a method that complies with all these requirements, which consists in a unit that simulates the conditions of the different parts of the digestive tract of monogastrics and polygastrics, and at the same times allows the evaluation of the binder’s real efficacy at the end of the GI tract (binding % in the stomach – detachment % in the gut).
Table 1. Results of the evaluation of different binders against different mycotoxins in monogastrics with Biovet’s patented method
In vivo evaluation
At least two batches raised under the same environmental and management conditions are necessary to properly evaluate a mycotoxin binder in field. Each of them should receive a different mycotoxin binder (or one of them can be a blank group, without any binder).
After the administration of contaminated feed, the following parameters should be evaluated:
- Productive performance: productivity will be negatively affected if the binder’s efficacy is low.
- Lesions in target organs: necropsy several animals to evaluate lesions in their organs that match the effects of the mycotoxins. Sometimes, the effects may be visible prior to performing necropsies (see image 1).
- Relative organs weight: the comparison of the organs weight with the animal weight can determinate the organ efficiency (a higher relative weight means less efficiency). Mycotoxins reduce the efficiency of the organs (gut, liver) and, therefore, increase their relative weight.
- Other complex parameters can be evaluated, such as the presence of mycotoxins or their metabolites in feaces, to calculate the amount of mycotoxin that has been absorbed in the gut.
Results obtained to evaluate the binder’s efficacy to bind zearalenone in sows (which are very sensitive to the estrogenic effects of this mycotoxin) are described below.
The aim of the trial was to evaluate the efficacy of Silicoglycidol (patented molecule) to bind zearalenone (ZEA) by the analysis of the concentrations of ZEA and its metabolite in feaces. ZEA-contaminated feed was given to sows and the concentration of this mycotoxin and its metabolite, zearalenol (ZOL), were evaluated.
- A higher concentration of ZEA in feaces indicates that the mycotoxin has not been absorbed.
- A higher concentration of ZOL in faeces indicates that the mycotoxins has been absorbed and metabolized, therefore, the mycotoxin binder is not very effective.
- T1 – Negative control: feed without mycotoxins, no binder
- T2 – Positive control: contaminated feed with 1 ppm of ZEA, no binder
- T3 – Binder: contaminated feed with 1 ppm of ZEA) with Silicoglycidol at 0,5 kg/t
There was more presence of ZEA and less presence of ZOL in the batch with the mycotoxin binder, compared with the batch without the binder. This demonstrates that the binder was able to avoid the absorption of mycotoxin and the its metabolization in the liver.
In conclusion, Silicoglycidol effectively binds zearalenone and avoids its absorption in sows, which has a positive effect on reproductive parameters.
Summary of the article
Mycotoxin binders are a good tool to prevent the negative effects of these toxic compounds and prevent their entrance in the food chain.
Main picture: Aspergillus. Author: John Wetzel at wikipremed.com
MV. Júlia Pié Orpí
Veterinary Technical support to the area of Latin America at Biovet S.A. Laboratories Official Veterinary Services (SVO) in poultry slaughterhouse