Adverse effects of Mycotoxins in animals and Holistic Mycotoxin Risk Management Program

Mycotoxins are secondary metabolites of fungi/mould that cause toxic, non-infectious disease in the animals that ingest them. There are over 200 species of moulds that produce above 600+ mycotoxins, some of which are only synthesised by one organism and some of which are synthesised by many, and therefore have several potential clinical manifestations.

Synthesis of mycotoxins is induced by complex relationships between genetic composition and the environment; therefore, the presence of a specific organism does not confirm the presence of a toxin.

Moulds that can produce mycotoxins grow on numerous crops/food and feed ingredients such as maize, bajra, cereals, nuts etc. Mould growth can occur either before harvest or after harvest, during storage, on/in the food itself often under warm, damp, and humid conditions. Climate and environmental factors like drought, frost, hail, rain at harvest, flooding, weather changes, unusual climate patterns influence mycotoxin production.

Mycotoxin production in crops depends on planting density, harvesting technique, changes in agricultural practices, susceptible plants varieties, fungicidal agents and also mould strains. E.g. in substrates like peanuts, rice, sorghum, wheat, corn, strains of Aspergillus parasiticus NRRL 3000 and NRRL 2999 can produce 107,107,72,72,53 mg/kg (ppm) and 104, 185,88,19,47 mg/kg of aflatoxins respectively. However, the production of aflatoxins in soya meal is only 19 and 2.8 mg/kg respectively. The strain NRRL 3145 produces 8.5,10.6 ,57.6 ,7.10 and 5.5 mg/kg of aflatoxins in peanuts, rice, sorghum, wheat, corn, respectively; but the production of aflatoxins in soya meal is significantly lower ,around 0.06 mg/kg . Therefore, under optimal temperature and *water activity (aW) conditions, mycotoxin production depends on genetic strain and substrate composition.

*Water activity(aW)-Defined as energy status of water.

Classification and Characteristics of Mould and Mycotoxins: Moulds and mycotoxins can be field origin, storage origin or both. Mycotoxins are invisible, odorless, tasteless, heat stable during feed processing, omnipresent in feed ingredients and have major impact on the growth and health of livestock & poultry, fish, shrimp. When it comes to animal health and performance, six mycotoxins have most detrimental effects. These are referred to as Big Six namely Aflatoxin, Ochratoxin, Zearalenone, Fumonisins, HT2 and Deoxynivalenol.

Fig 1 - Temperature distribution of various mycotoxins

They have a wide bandwidth for temperature tolerance and can thrive in extreme temperatures.

Adapted From Chapter 10, Mycotoxin Blue Book, 2005

Some foods and feeds are often contaminated by numerous mycotoxins, but most studies have focused on the occurrence and toxicology of a single mycotoxin. Regulations throughout the world do not consider the combined effects of mycotoxins. However, several surveys have reported the natural co-occurrence of mycotoxins from all over the world. Most of the published data has concerned the major mycotoxins aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEA), fumonisins (FUM) and trichothecenes (TCTs), especially deoxynivalenol (DON). Studies of mycotoxin combination toxicity showed antagonist, additive or synergic effects depending on the tested species, cell model or mixture, and were not necessarily time or dose dependent.

Most significant mycotoxins and mycotoxicosis affecting various animals: A Mycotoxicosis is a disease caused by ingestion of mycotoxin by animal. There are several factors that can influence the toxicity of mycotoxins in animals. Some of the factors are:

• Animal species and breed.
• Mycotoxin concentration.
• Exposure duration.
• Animals’ nutrition and overall health status.
• Age and sex.
• Co contamination with multiple mycotoxins.

Methods of detection of mycotoxins in raw materials and feed:

Determination of mycotoxin levels in various food, feed and feed ingredients is a challenging exercise because of the problems associated with sampling of heterogeneously distributed compounds and the fact that the analytical methods need to have low limits of detection generally in range of mg/kg (ppm) or µg/kg (ppb) depending upon the mycotoxin being analysed. Analysis at the very low level of detection and quantification requires a very high specificity to avoid analytical interferences and uncertainties. A sustained international effort is being made to develop and improve the methods for detecting and quantifying the mycotoxins.

Current tools: The methods employed for the mycotoxin analysis mostly fall into the general categories of either chromatographic methods or immunological methods. All these analytical methods require solvent extraction of the mycotoxin from the matrix. For chromatographic analysis, the next step involves extract clean-up followed by concentration. Another component of the complexity in mycotoxin analysis is the varied chemical and structural properties of mycotoxins. This makes the requirement of developing specific method for individual mycotoxin. However, this challenge has been successfully overcome using expensive and sophisticated mass spectrometric methods. Hence, when selecting a method for mycotoxin analysis one should consider the purpose for which the results are needed; the matrix to be analysed; the detection limit required and the availability of expertise and infrastructure. Over the years various tools and methods have been developed to detect and estimate the mycotoxin levels.

One such technology that has been standardized and validated by Trouw Nutrition is – Mycomaster. Mycomaster is a rapid, cost effective and easy to use mycotoxin detection system, which can be operated outside the laboratory. The system works on principle of quantitative Lateral flow immuno assay (LFIA) technique. Mycomaster offers an accurate yet easy to use alternative as it enables feed millers and integrators to analyse the mycotoxin levels within matter of minutes at the site itself. Since no laboratory facilities are required, the costs are also only 20-25% of the average price for conventional HPLC testing. Table 1 outlines approximate cost and time requirement for the analysis using different methods.

Table 2. Mycotoxin analysis time and cost comparison

Since mycotoxins are omnipresent and they have significant impact on the livestock and poultry health and performance, it is important to have a holistic management program to mitigate the risks arising from mycotoxins.

 MYCOTOXIN RISK MANAGEMENT

1.Risk Identification and Assessment:

Trouw Nutrition globally as well as Trouw Nutrition India regularly screens feed raw materials and finished feeds in Masterlab in Netherlands and Customer Service Lab (CSL) in Jadcherla respectively.

Fig.2 Summary of Total Mycotoxin contamination for different mycotoxins.

Seasonal Impact On Mycotoxin Concentrations:

Fig 8: Effects of seasons in Aflatoxin prevalence 2022

Mycotoxin concentrations in corn change throughout the year depending on the growing conditions in the field as well as storage conditions. As can be seen in the Fig.9; AF concentrations showed three peaks in the year in the months of February, July, and October. Each one of the mycotoxins showed different peaks indicating the differences in the conditions required for their production. The sizeable quantity of corn produced in 2022 will be used at least until Q1 of 2023 and hence studying such month-to-month variations can provide some tips for effective mycotoxin risk management.

2) Implement Risk Control Measures:

We can summarise the effects of multiple mycotoxins as the following:

• Organ health: Liver, Bursa, Spleen, Testes, kidneys.
• Mycotoxins responsible for Immunosuppression: Animals susceptible to secondary diseases. Inhibition of immunoglobulin synthesis.
• Mycotoxins responsible for gut health integrity: Necrotic enteritis, Coccidiosis, Gizzard erosion, Wet droppings.

It is important to use a mycotoxin binder to mitigate the effects of the mycotoxins. Adsorbent in mycotoxin binders binds the mycotoxins in the feed strongly enough to prevent the adsorption across the digestive tract of the consuming animal.

This is one aspect of mitigating mycotoxin risk but lacks holistic approach. Trouw Nutrition believes in implementing 3D approach of mitigating mycotoxin risk in animals.

What is 3D approach?

It is an integrated approach which focuses on 3-dimensional aspect(3D). First is the mycotoxin binding, second is Gut wall protection and third is Immune modulation.

• Bentonites (>80 % smectites) ensures more than 90 % binding of polar mycotoxins without binding with minerals and vitamins.
• Gut wall protection: Glucose biopolymers help to reinforce gut integrity and preventing mycotoxins and endotoxins to evade the intestinal barrier into the blood stream.
• Immune suppression: Common effects of mycotoxin in animals. Exposed beta glucans help in immunity by positively compensating macrophage activity, lymphocyte proliferation and vaccine efficacy.

3)Evaluate Effects:

Routine screening of raw materials and finished feeds with available tools, monitoring performance and health records regularly is a comprehensive way to mitigate the risk posed by mycotoxins in animal health and performance.

To summarize, mycotoxins and managing the threats due to mycotoxicosis is complex due to presence of mycotoxins in almost all raw materials and feed. The permissible level guidelines must be met but is not the only criteria to control chronic mycotoxicosis due to synergies and additive effects amongst them. Moreover, there are masked mycotoxins, emerging mycotoxins and new species identified almost every year makes them harder to manage. Holistic approach is the need of the hour – routine screening of raw materials, feed-risk identification and assessment by on spot devices like Mycomaster, Implementation of risk control measures (broad spectrum mycotoxin binder) and Risk control review.

For further information, kindly write to us at customercareindia@trouwnutrition.com or visit our website: www.trouwnutrition.in