Toxicity of mycotoxins and risk assessment
In mycotoxins risk management, prevention is the key point for success. It is vital that feed producers know the contamination levels and the associated risks per specie in order to have a preventative approach.
BY FRANCISCO PINTO, BUSINESS DEVELOPMENT MANAGER, WISIUM M
ycotoxins are toxic secondary molecules produced by moulds. These molecules can cause a wide range of effects depending on the molecular family, combination of contaminants
and rearing environment. They occur differently in each part of the world, according to climate and agricultural practices. Aflatoxins, Ochratoxins, Fumonisins, Zearalenones and Trichothecenes (DON, T2, H-T2, etc.) are the five main identified mycotoxins families causing a lot of zootechnical issues with or without clinical effects. Mycotoxins contamination can occur in the field with moulds such as the Fusarium species, producing mycotoxins such as Fumonisins, Trichothecenes and Zearalenones on the crops. Contamination can also happen in storage with fungi, such as the Aspergillus and Penicillium. Those fungi are linked to Aflatoxins and Ochratoxins. One mycotoxin can be produced by several moulds and one mould can produce several mycotoxins, causing multiple contamination. Nowadays, nearly all samples that have a positive result for mycotoxin presence are in this situation.
Evaluation of the contamination Raw materials analysis is the starting point of mycotoxins contamination knowledge in each particular situation. Corn, barley, wheat and oats are important substrates, but they are not the only raw materials that need to be analysed. For rumi- nants, forages are the main source of contamination which also need to be analysed. Mycotoxins contamination can be suspected by moulds presence, or fermented grains. But in most cases, contamination cannot be suspected and detected by visual inspection, even at high levels. Sometimes, there is no alteration of the external aspect, no smell, no taste, no insects. No physical sign of contamination does not mean no contamination at all. Even good-looking raw materials can have a higher contamination level than bad looking ones. Only analysis can confirm the presence of mycotoxins.
14 ▶ MYCOTOXINS | NOVEMBER 2021
To have a representative analysis, you need to have the right sample. The main challenge is to collect a representative sam- ple of your feed knowing that these molecules have a hetero- geneous mode of distribution. That is why it is crucial to use the proper sampling method to have a representative sample for analysis. Specific methodologies are developed per type of raw materials and types of delivery. In addition, mycotoxins are very stable and resistant metabolites. They are resistant to ther- mic treatments up to 250°C (such as extrusion, pelletising, flacking etc.), physical and chemical treatments (such as clean- ing and ammoniac), fermentation, moulds inhibitor during storage (such as organic acids which destroy only fungus and not the mycotoxins) and time (even long storage periods). In turn, these toxic molecules represent a threat for animal species as much as for humans because they compromise an- imals’ immune system and food safety. To avoid their negative impacts on animals’ performance, they need to be protected by a global insurance linking personalised raw materials con- trol plan services and efficient product solutions.
Table 1 – Aflatoxin B1 oral LD50 of various animals’ species.
Species
Chick embryo Duck
Turkey
Chicken Sheep
Rat (male)
Rat (female) Rabbit Cat Pig
Guinea pig Hamster Mouse
Source : D.Dhanasekaran et al., 2011
Oral LD50 (mg/kg BW) 0.025 0.3 0.5 6.3 5.0 7.2
17.9 0.3 0.6 0.6 1.4
10.2 9.0
PHOTO: OLESHKO ARTEM
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