Mycotoxin mitigation for conventional and unconventional feed ingredients

The present survey shows a higher level of mycotoxin levels in unconventional feed raw materials compared to conventional raw materials like soybean and corn. What does that imply for a feed miller?

The outcome of Cargill Mycotoxin Survey indicates, unconventional/Industrial by-products always pose a serious threat to poultry health and performance. The mycotoxin contamination is quite high, in groundnut by-products (76%), Corn Gluten Meal (64%), Dried Distillers Grains (88%), and Rice by-products (87%). Even the level of all analyzed mycotoxins – Aflatoxin, Fumonisin, T2 & Zearalenone is significantly higher indicating a threat of multi mycotoxin, which will exert multifold negative impact on poultry due to synergistic & additive effects.

These higher levels of mycotoxins indicate poor processing infrastructure of these industrial by-products, improper drying & substandard storage facility. Generally, raw ingredients are susceptible to fungal infections producing mycotoxins. Due to the concentration that non-starch components undergo during the distillery process, mycotoxin concentrations are about three-fold in distillers’ grain and solubles compared to the original grain.

Feed Millers should use these feed ingredients with utmost precautions and in limited quantities. It is always advised to check for contamination of unconventional raw materials before formulation.

What would be the ideal inclusion level of ingredients like Groundnut by-products, DDGS, Rice by-products, etc. for a safe formulation?

According to Cargill Mycotoxin Survey, Industrial by-products are found to be highly contaminated with multi-mycotoxins which can lead to reduced performance or high mortality as per the contamination level.

The ideal inclusion level of ingredients can be decided after analyzing high-risk ingredients (DDGS, CGM, DORB/rice polish, and ground nut cake/meal) for mycotoxins. As the same ingredient can be of good quality if processed & stored in proper condition. Simultaneously, it can drastically create havoc, if contaminated ingredients are being used in higher proportions without analyzing.

In 95% of cases, ground nut cake/meal is contaminated beyond tolerance level. As per the survey, the average contamination level is 73 ppb for aflatoxin in ground nut cake/meal with a maximum of 323 ppb. DDGS is contaminated at an average of 61 ppb with a maximum of 221 ppb for aflatoxin. DORB could prove to be the most harmful ingredient due to the high level of aflatoxin contamination (average 30 ppb with maximum 268 ppb) followed by fumonisin (maximum 4160 ppb) & T2 (maximum 784 ppb).

It is always advisable to analyze high-risk ingredients and include them in feed formulations in addition to the anti-mycotoxin agent (AMA). if the risk level is consistently low, the formulation can be adjusted to reduce anti-mycotoxin agent (AMA) usage. If the risk remains low, testing frequency can also be reduced. However, if a user consistently finds that the risk level for one or multiple mycotoxins remains at the medium or high level, we will recommend the correct level of specific AMAs to counteract the mycotoxins present. Continued testing to monitor risk levels and adjust agent use is also recommended.

How do you see the mycotoxin prevalence issue in India compared to other Asian countries? What tips would you like to give a feed miller for post-harvest storage?

In India, 4811 mycotoxin analyses have been conducted from January – November’22 & almost 98% of analyses were found to be contaminated & almost 75% of analyses were above performance risk level. Therefore, Mycotoxin contamination represents a high serious risk in India as compared to other Asian countries due to its favorable climatic condition for mold development & substandard storage facility. Almost 77% of samples were above risk level for aflatoxin followed by T2, Fumonisin & Zearalenone 69%, 58%, and 54% respectively for ingredients predominantly used in the poultry industry in India.

It is always said that prevention is better than cure so the following measures have to be taken during post harvest storage to mitigate the mycotoxin issue:

  • Purchase clean feed ingredients
  • Monitor feed ingredients for levels of mycotoxins
  • Keep the moisture of grains less than 12%.
  • Store the feed and ingredients in a well-ventilated dry place, on wooden pallets and way from walls to prevent moisture absorption
  • First In First Out (FIFO) has to be practiced
  • The most practical way: use of mold inhibitors and broad-spectrum toxin binders.
  • In the case of silos, ensure that adequate ventilation with centrifugal fans and temperature control is in place.

What are the latest technologies in mycotoxin analysis?

There are various tools available for Mycotoxin analysis, e.g.

  • TLC: Thin Layer Chromatography
  • HPLC: High-Performance Liquid Chromatography
  • HPTLC: High-Performance Thin Layer Chromatography
  • GC: Gas Chromatography
  • LC-MS: Liquid Chromatography with Mass Spectrometric Detection
  • EIA/ELISA: Enzyme-Linked Immunosorbent Assay
  • Latéral Flow technique/strip-based method

One can choose the method based on requirements. The gold standard for mycotoxin analysis is LCMS, but it is very sophisticated, time-consuming & costly. If the sample load is high for mycotoxin analysis, then samples can be analyzed through ELISA & if the sample load is comparatively low, rapid kits based on lateral flow can be utilized, but We need to focus on validation and calibration of such kits to get reliable results. Method/ tool can be decided as per urgency and cost-effectiveness for the user.

Mycotoxins are not equally distributed in whole lots/batches and are found in hotspots; therefore, the Quartering Sampling technique has to be followed to get a representative sample from a whole lot/batch/truck.

Would you please throw some light on the impact of climate change on the mycotoxin issue?

The rise in contamination rates is likely due in part, to climate change, as well. Since mycotoxins are produced by molds as a natural defence response to environmental factors, their occurrence is linked to climate conditions. As a result, changing weather patterns can lead to substantial changes in mycotoxin distribution, frequency, and spread. In a changing climate, mycotoxins will contaminate new geographical areas and crops, and we expect this trend to continue, and possibly even accelerate, over the next five years.

India is facing an unseasonal rain pattern affecting pre-harvest mold development at a faster rate & the hot climate exerts stress on the mold to release mycotoxins simultaneously.

Is there any one-size-fits-all kind of strategy for mycotoxin risk management? What according to you is the best mycotoxin mitigation strategy?

Hundreds of mycotoxins are known and of mild to severe toxicity. Mycotoxins can have additive or synergistic interactions with other natural toxins, infectious agents, and nutritional deficiencies. Many are chemically stable and maintain toxicity over time. The fungus that is usually involved in the deterioration of grain have been classified as field fungi, storage fungi, and advanced decay fungi depending on the time of their invasion and colonization of grains before or post-harvest Mycotoxin contamination found in complete feed is often from multiple ingredients, regularly resulting in flock exposure to multiple mycotoxins over the course of their time in production.

Each mycotoxin has a different structure and polarity. Some are larger in molecular size and some are smaller making them easily absorbable in the gut. The difference in chemical and physical characteristics of mycotoxins makes them more complicated and needs a different approach for each of them.

Therefore, a Single strategy cannot be applied to mitigate all kinds of mycotoxins & multipronged strategies have to be followed to combat mycotoxin issue.

by Dr Nidhi Madnawat, Cargill India