Natural toxins produced by moulds on animal feedstuffs are increasing worldwide –partly as a result of climate change – and nutritionists are taking their potential to cause significant animal health and performance issues increasingly seriously. But improved surveillance, analysis and remediation techniques are now helping the feed industry counter the progressively complex mycotoxin challenge.
Head of R&D and Technical
Volac International
The mycotoxin threat to optimal livestock performance is increasing in many countries around the world. Mycotoxins are secondary metabolites produced by moulds on animal feedstuffs that possess the potential to derail efficient ruminant and monogastric production. Adverse impacts include lost milk, poor growth rates, depressed animal health and even fertility challenges.
Some mycotoxin production by fungi in feed raw materials, such as cereals, is catalysed by the presence of warm, dry growing conditions; and some mycotoxin producing fungi grow well in cool, wet situations. Other stresses to plants can also trigger the production of mycotoxins – mycotoxin production is not only impacted by weather. Although it is suspected that there are many undiscovered mycotoxins, those known to cause significant challenges to optimal animal production are generally produced by the Aspergillus, Fusarium and Penicillium genera of fungi.
There is no doubt that mycotoxin prevalence is increasing globally; common toxins previously usually only found in certain parts of the world are now being discovered in other areas. This is in part due to a better analysis and surveillance of raw materials, but also because of climate change. For example, aflatoxin – a common mycotoxin produced by Aspergillus fungi that is usually found in hotter climates, is now also being detected in more northern geographies.
Ruminant animals are better able to deal with aflatoxins, although there is understandable concern about the potential of carryover of the major metabolite of aflatoxin (aflatoxin M1) into milk and its carcinogenic effect in humans. Consequently, there are regulated limits worldwide for aflatoxins in feed.
On the other hand, poultry are particularly susceptible to aflatoxins, with impaired immune function and reproductive efficiency, liver damage, poor shell quality, reduced egg production and low carcass quality being common signs associated with feed contamination. Pigs are also susceptible to aflatoxins, with the hepatic disease (liver damage) being a particular challenge.
Consequently, the feed industry has developed several approaches designed to detoxify mycotoxins and these include physical, chemical and biotransformation strategies.
Physical remediation strategies include the use of adsorption agents, whereas a chemical approach focuses on the use of oxidising agents, aldehydes, acids or bases.
These different mitigation strategies have strengths and weaknesses. For example, chemical strategies may be effective in some situations, but understandably raise concerns about harmful residues in feed and food. And while physical remediation strategies are appropriate to counter the threat of some mycotoxins such as aflatoxin, others require biotransformation due to their physical structure.
An example of a mycotoxin that requires biotransformation to reduce its toxic effect is zearalenone (ZON). ZON is an oestrogenic toxin, in that it mimics the effect of the reproductive hormone oestrogen. Consequently, it has an impact on animal fertility. ZON may influence fertility by decreasing lutropin and progesterone secretion and altering the morphology of uterine tissues. In male animals, ZON is associated with reduced serum testosterone, testes weight and spermatogenesis.
Whilst the impact of ZON is not as concerning from a human health perspective as the threat posed by aflatoxins, it is still important to counter potential feed contamination because of the adverse effects on livestock production and fertility. ZON also presents a challenge in that its effects may not be seen until it is too late – invariably when later in the production cycle fertility challenges are observed.
From a remediation perspective, research has shown that UltraSorb can transform ZON (see figure 1) leading to ZON concentration reduction and an increase in the daughter metabolites, α-ZOL and β-ZOL. The production of these daughter metabolites demonstrates that ZON has been transformed. In addition, other components within UltraSorb can physically bind the daughter metabolites following the biotransformation.
Consequently, use of a mycotoxin remediation feed additive product with functionality to transform ZON is important – as is the need to consider different remediation products for different species.
When considering the functionality of a mycotoxin remediator, the specifics of different species’ digestive tracts must be considered. For example, some ingredients and formulations will have better binding efficacy under different pH conditions. Research at the Volac Technical Hub has shown that different materials differ in binding affinity across pH3 and pH7 – highlighting the importance of selecting ingredients for a species-specific approach (see figure 2).
The Volac UltraSorb mycotoxin remediation range has been specifically developed and formulated for different species applications. Bespoke ruminant, swine, pig and aqua UltraSorb formulations allow nutritionists to select the most appropriate product by target species – and be confident the right remediation strategy has been selected to counter the potential adverse impacts of various mycotoxins on animal health and performance.
About Dr Sophie Parker-Norman
Dr Sophie Parker-Norman has worked in the global ruminant and monogastric feed industries developing novel feed additive and technical service applications. Dr Parker-Norman leads the R&D and Technical Development team at Volac International Ltd and has academic foundations in animal immunology and epidemiology.
