Brazil challenges the Anti-Mycotoxins Additives

 

 

Among the physical, chemical and biological methods that are available against mycotoxins (CAST, 2003; Gimeno & Martins, 2006), we have the use of Anti-Mycotoxins Additives (AMA). Most of them act by a quimi-adsorption effect inside the animal and should have an effective capacity to bond the mycotoxins and block them in the gastrointestinal tract. They should form a stable and irreversible compound that later is eliminated by the feces, therefore the mycotoxin bio-disponibility is reduced and the undesirable effects that this produces are avoided. These products are usually denominated as mycotoxin adsorbents and they are included in the AMA group.

Other AMA's act by enzymatic and/or bacterial processes inside the animal and bio-transform the mycotoxins in derivative compounds which can be in general and not always less toxic or not toxic.

It is very important to be careful with the use of these enzymes and/or bacteria bio-transformers since it is necessary to know exactly which are their characteristics and their biotransformation yields; For example, the mycotoxin zearalenone can become the isomers alpha and beta zearalenol of which the alpha zearalenol is from 3 to 4 times more estrogenic than the zearalenone.

In the rumen of the cow and of other ruminants, this biotransformation is carried out by the ruminal fluid and the rumen protozoa microflora occurs frequently and zearalenone is degraded to approximately 90% becoming alpha and beta-zearalenol.

For trichotecene mycotoxins, the biotransformation processes should be irreversible and should arrive in final chemical form of DEEPOXI that is non toxic. If some of the intermediate compounds that are formed in these biotransformation remain as residues can be as much or more toxic that the original mycotoxin. Since the objective is that the biotransformation are made, it is necessary to make sure that there are no toxicity risks neither for the animals as well as for the humans because some of those intermediate compounds can remain as toxic residues in edible animal tissues (liver, kidneys, muscle).

In those countries where antibiotics are not used in the feed or in the drinking water there is no problem with the use of beneficial bacteria that biotransformation the mycotoxins. If antibiotics are used in the feed or in the drinking water it is very important to make an analysis of the minimum inhibitory antibiotic concentration against the used beneficial bacteria in order to be sure that it has not been destroyed. This occurs frequently with beneficial bacteria losing the benefit made by the AMA due to lack of effectiveness against the mycotoxins and consequently carrying further the problems in the animals.It is also important to have in consideration that these enzymes and/or bacteria biotransformers are not usually termoresistants and very important losses of them can occur during the pelleting and expander processes.

Nowadays, there is great variety of AMA and there is an unsystematic use of them all. Many times the effectiveness and action spectrum of some of them are questionable and even absorb certain nutrients.

Inside the AMA there is a group that claims to have the effect of an AMA but these ones mask and/or reduce the secondary effects caused by the mycotoxins; for example they claim to improve the response of the immune system and/or productive parameters but they don't protect the organ that the mycotoxin is affecting and/or destroying. This can be observed easily through a proper pathological and histopathological analysis and some times, macro observation is enough.

 It's true that is still very necessary to study and improve the effectiveness of these AMA, fortunately we now have a weapon in the fight against the mycotoxins that we didn't have before.

Brazil has proposed and has accomplished in establishing the use of some protocols for the evaluation of these AMA as authorized additives and that can be used with some guarantees for the animal feeding.

According to the order in council No. 13 of 24 May 2006, published in the Diario Oficial da União in Brazil on May 25th 2006, in section 2, page 6, a Working Group was constituted on mycotoxins in products intended for animal feed (see the link in the bibliography), according to the resolution of the Minister of the Agriculture, Livestock and Supplying, in the use of the attribution that confers him the art. 87, unique paragraph, clause II of the Constitution and that is listed in the Process No. 21000.005214/2006-46.

The member Institutions of this working group were:

Ministério da Agricultura, Pecuária  e Abastecimento - MAPA

Instituto Adolfo Lutz - IAL

Agência Nacional de Vigilância Sanitária - ANVISA

Universidade de São Paulo - USP

Universidade Federal de Santa María - UFSM

In each one of those Institutions there is a group of people responsible for the development of this matter (see link).

Among several attributions (see link) regarding mycotoxins that were conferred to the Working Group, one of them consisted in the "Re-evaluation of the use of mycotoxins adsorbents authorized as additives in the animal feed"

The expression "mycotoxins adsorbents", a proposal was submitted for it to be substituted by the general denomination of "Anti-Mycotoxins Additives (AMA)", making it clear this denomination includes the products that we add to the feed for animals and are capable to Adsorb, Deactivate, Neutralize and Biotransform the mycotoxins.

Due to the extensive length, I won't expose the complete content of these protocols but rather provide brief and clear detail of them.

1.1.1.2. - The results of "in vitro" trials should be presented proving the capacity of the anti-mycotoxin, with a criterion of quality control of the product, at pH 3 simulating this capacity in gastric juice and at pH 6 simulating the same one in the intestinal juice. The gastric and intestinal juices will be standards USP (United States Pharmacopeia). The method used for those essays should be indicated.

For each pH, 5 groups should be prepared in 5 test tubes in each group with 0, 25, 50, 75 and 100% in each tube respectively, of the AMA maximum recommended dose by the manufacturer and a concentration of mycotoxins such as aflatoxin B1(AFB1), zearalenone (ZEN), ocratoxina A (OTA), fumonisin B1 (FB1) and deoxynivalenol (DON) of 1,0; 1,0; 1,0; 2,5 and 2,5 ppm (milligrams/Kg), respectively, in each one of the test tubes. A minimum of 3 replicas by tube should be done and after the mycotoxin analysis in each one of the tubes, the anti-mycotoxin action will be checked in function of the dose of inclusion of the AMA in the diet and comparing the results with those of the tube that AMA doesn't contain.

It is common practice to maintain the mycotoxin in contact with the AMA during 1 hour at 37ºC in constant agitation.

The "in vitro" results in questions indicate only its efficiency of the same but they will not be, in any way, conclusive for the final approval of the AMA. They will only be for orientation needing results of the trial "in vivo"

1.1.2.1. - Four groups of animals will be used. Each group will have the following feed:

Group 1: Mixed feed control (not contaminated).

Group 2: Mixed feed not contaminated + AMA in the maximum dose recommended by the manufacturer.

Group 3: Mixed feed contaminated with the specific mycotoxin for the Trial and in the concentration indicated in 1.1.2.2.

Group 4: Mixed feed contaminated with the specific mycotoxin for the Trial and in the concentration indicated in 1.1.2.2 + AMA in the maximal dose recommended by the manufacturer.

For poultry, it should have a minimum of 6 experimental units with 10 birds in each one.

For pigs, bovine, horses, dogs and cats there will be a minimum of 6 animals for each one of 6 experimental units.

1.1.2.2.- Next, we indicate the selected mycotoxins, the concentration of the same ones to add in the mixed feed as contaminants and the parameters to study and to take into account according to the toxic effects of these mycotoxins, will be indicated.

a. - For aflatoxins B1, B2, G1 and G2. The level in the diet will be of 1-3 ppm (mg/Kg) of total aflatoxins and the parameters to be studied will be: alterations in the development (daily body weight gain, daily feed intake and feed conversion), serum proteins, hepatic enzymes and in the relative liver weight and kidneys.

Preferably, the strain of Aspergillus flavus or/and parasiticus used for contaminating the mixed feed, it should produces 84% of aflatoxin B1, approximately. Therefore, the aflatoxin B1 will be the predominant inside that range of contamination of 1-3 ppm.

b. - For aflatoxin B1. The level in the concentration for animal milk producers will be of 5 ppm and the parameter to be studied will be: the aflatoxin M1 residues in the milk.

c. - For zearalenone. The level in the diet will be of 0,25-2 ppm and the parameters to be studied will be: alterations of the vulva and of the length and weight of the females reproductive tract.

d. - For ocratoxin A. The level in the diet will be of 2-4 ppm and the parameters to be studied will be: alterations in the development (daily body weight gain, daily feed intake and feed conversion), serum proteins, uric acid and in the weight of the liver and kidneys.

e. - For deoxynivalenol. The level in the diet will be of 5-15 ppm and the parameters to be studied will be: alterations in the development (daily body weight gain, daily feed intake and feed conversion) and in the serum proteins.

f. - For fumonisin B1. The level in the diet will be of 50-200 ppm and the parameters to be studied will be: alterations in the development (daily body weight gain, daily feed intake and feed conversion), serum proteins, sphinganine/sphingosine ratio and in the relative weight of the liver and the lungs in pigs.

1.1.2.3.- The obtained results for each one of the diets will be compared with the results of the control diet and a statistical study will be made with all the inherent parameters in the study. It will be indicated which was the statistical method used and the conclusions according to the results obtained in the study.

1.1.2.4.- Other results like the analyses of dioxins residues, lead, cadmium, mercury and arsenic in the AMA containing aluminosilicates and even of Salmonella spp (chemical and microbiological contaminants) should be presented and they will have to agree with the maximum limits which are allowed in the different European Union (EU) directives.

For other AMA not containing aluminosilicates, only Salmonella sp analysis will be presented.

 

 

Other attributions concerning mycotoxins were conferred to the Working Group before mentioned, such as: evaluate the Brazilian situation of mycotoxins contamination levels in products intended for animal feeds in light of food security and define criteria for the control of mycotoxins.  

It is obvious that all which was exposed up to now and other things can be criticized and subject to improvements and modifications. However, I believe that mainly it should be enhanced in a very positive way and it deserves the congratulations of the Brazil Government and all members of the above mentioned Working Group, for the importance achieved in this fight against the mycotoxins with the use of some AMA that really work and are effectives.

I think that this can be an example for other countries to follow.

 

 

CAST (Council for Agricultural Science and Technology) (2003). Mycotoxins: Risks in Plant, Animal, and Human Systems; Council for Agricultural Science and Technology, Ames, Iowa, USA; Task Force Report nº 139, January 2003, pp. 1-199.    

Gimeno, A. and Martins, M.L. (2006). Mycotoxins and Mycotoxicosis in Animals and Humans. Special Nutrients, Inc. USA (Ed.). Victor Mireles Communications, Mexico City (Mexico). pp. 1-127.