Trouw Nutrition, Nutreco’s livestock feed business, is sharing results from a global mycotoxin analysis of complete feeds and raw materials sampled in 2021. The almost 32,000 samples collected and analyzed globally, showed mycotoxin contamination ranging from 18 to 63%, with the highest being aflatoxin (AFLA) contamination and the lowest for T-2/HT2 toxin (T2HT2). Based on the mycotoxin concentrations (ppb), mycotoxin risk was the highest for pet food and aqua feed followed by ruminants, pigs, and poultry feeds. These results show a need for proper sampling and analysis of feeds and raw materials to assess contamination threats and introduce targeted mycotoxin mitigation strategies that respond to emerging concerns. 

THE NEED FOR MYCOTOXIN ANALYSIS

Understanding the mycotoxins present in feed ingredients and complete feeds is necessary to provide safe feed for efficient production as toxin contamination can impair animal health and performance. Knowledge of mycotoxin presence also plays a role in safe food production because some mycotoxins can be transmitted into animal proteins including milk, eggs, and meat. This transfer has led to regulatory limits in some areas.

When ingredients and feeds are checked for mycotoxin contamination, priority is given to a selection of “Big 6” mycotoxins such as deoxynivalenol (DON), T-2HT2, zearalenone (ZEA), fumonisins (FUM), AFLA and ochratoxin (OTA). All six, and many other mycotoxins belong to one of four toxin groups – fusarium toxins, aspergillus toxins, penicillium toxins and ergot toxins. 

Mycotoxin monitoring can be done at several different points in time – after crops are harvested in the field, while ingredients are at the feed mill and after a complete feed is mixed. Trouw Nutrition mainly uses Mycomaster, lateral flow technology, for the analysis of “Big 6” mycotoxins but also uses LC-MS/MS for silage and TMR analysis. Mycotoxin interpretation tools such as Mycotoxin Monitor, which provides a regional risk analysis for specific species, and Mycotoxin Adviser, which provides customer- and species-specific feedback, are used by Nutreco colleagues and customers across the world.

WHAT IS THE DIFFERENCE BETWEEN % MYCOTOXIN CONTAMINATION AND CONCENTRATIONS?

A few key terms are important for the better understanding of the mycotoxin data interpretation: % contamination refers to the number of commodities, out of 100, when tested were found to have mycotoxin concentrations at and above the level of detection (LOD). Mycotoxin concentration, on the other hand, means the amount of a specific mycotoxin present in one kg of feed or raw material and the amount should be at and above limit of quantification (LOQ).  It is usually expressed in ppb (µg per kg feed) or ppm (mg per kg feed). 

The % contaminated with mycotoxins indicates the prevalence of mycotoxins in various commodities and regions whereas concentrations help in understanding the potential toxicity of feeding mycotoxin-contaminated commodities to various species of animals on a specific farm. A feed with the same level of a specific mycotoxin can elicit different toxic responses in different species of animals. 

DATASET OVERVIEW

Close to 32,000 analyses performed in this dataset represented 43 countries grouped into 5 regions (Figure 1). The highest % of samples were from Europe followed by North America, LATAM, MEA and Asia regions. Feeds contributed the maximum to the dataset (39%) followed by grains (35%), grain by-products, protein meals, silages, and other protein products. Maize, wheat, and barley were the major grains tested while soybean meal, sunflower meal and cotton seed meal were the chief protein meals. Many by-products were part of the testing including wheat bran, maize DDGS, maize gluten meal, and maize flour. As in our previous survey, broiler feed, layer feed, pig feeds, and ruminant feeds made the bulk of feed samples tested but there were considerable number of silages, pet food and aqua feeds also featured in the 2021 survey. 

ANALYSIS OF ENTIRE DATASET

As can be seen in table 1, 89% of the samples tested positive for at least one mycotoxin when LOD filter was not applied to the dataset (table 1). When analysis performed using rapid tests, instrument will display mycotoxin concentrations even below LOD. For example, if LOD is 3ppb for AFLA, the instrument will display results for 1 ppb and 2ppb also. We should not consider samples with 1 and 2ppb AFLA as positive samples. When respective LOD were applied to each mycotoxin, only 51% of samples were found to be contaminated and these are the correct figures. The two most found mycotoxins across all the samples were AFLA and ZEA, which were present in 63% and 53% of samples, respectively.

It is a routine practice in the industry to use average or mean to describe concentrations of mycotoxins in the commodities. Although this is easy to understand, the chances of data getting skewed is very high. Even if one or two sample out of 1000 samples tested contain high levels of a mycotoxin, the average of 1000 samples can be skewed to the upper side. For example, across the entire data set in this survey the minimum concentration of AFLA was 3ppb and the maximum found was 2,010ppb (table 1). Given the outliers in the data, the average concentration for AFLA was determined to be about 12ppb. However, the median, or central number in the data set, was 3ppb. Calculating the mycotoxin risk based on the average concentration, thus, may therefore overestimate the toxicity above what is really occurring. 

Box and Jitter Plot (Figure 2) provides a better picture of mycotoxin concentrations as it incorporates mean, median, quartiles and outliers into the analysis. It is clear from the Figure 2 that the variability within the dataset was the highest for AFLA followed by ZEA, T2HT2 and OTA. Variability was the lowest for FUMO and DON as the mean (diamond shape) was closer to the median (a line within the box).

Regionally, there was a variation in what mycotoxins were present in higher concentrations (Figure 3). For example, Asia reported the highest mycotoxin concentrations for AFLA, FUMO and DON, while North America had higher concentrations of OTA and T2HT2. LATAM reported higher concentrations of ZEA as compared to others.

RAW MATERIAL ANALYSIS

When looking specifically at raw materials harvested in 2021, with the potential of being used in feeds in 2022, primary mycotoxins sought in analyses

were present in most feed ingredients. The exceptions were that no samples of soybean meal tested positive for T-2 and no corn silage was found to have OTA (Figure 4). 

The range of contamination in different ingredients can be problematic when feed ingredients are combined. Mixing elements into a complete feed can add new mycotoxins or increase the percent contamination.

SPECIES RISKS

Not all species face the same risk from the presence of the same mycotoxin in feed. For example, swine can be highly sensitive to DON, while poultry aren’t. However, poultry are more sensitive to T2HT2 than either dairy cows or pigs. In addition to the type and concentration of mycotoxins making a difference, the duration of the exposure, the order in which animals experience mycotoxin negative effects, and the presence of other mycotoxins can influence response to mycotoxin contamination. 

Based on the practical mycotoxin guidance values (concentrations), species risk can be analyzed for various feeds analyzed in 2021 (table 2). To reduce the variability in the data, this year median values are considered for risk assessment rather than mean values. Overall, data showed low toxicity for poultry species, followed by low to medium toxicity for pigs, and low to high toxicity for ruminant and aqua species. Mycotoxins in dog foods showed maximum risk as dogs are quite sensitive to number of mycotoxins.

Looking into 2022, the assessment of samples collected in late 2021 through early 2022 has indicated high risk for dairy and piglets followed by sows and poultry. This assessment is based on the concentrations of AFLA, DON, FUM and ZEA in these feeds.

MYCOTOXIN MANAGEMENT

Although binding has long been part of the discussion with addressing mycotoxin presence in feeds, the recognition of multiple types of mycotoxins as problematic suggests that using several modes of action could be important to mitigation efforts. Binding alone may not address all mycotoxin challenges. However, because different mycotoxins can generate similar problems for the animal - like damaging the gut wall or suppressing immunity – supporting the organs damaged by mycotoxin presence is another mitigation practice. Using feed additives that provide a range of responses including adsorbing mycotoxins, supporting gut wall integrity and the immune system, and delivering antioxidants helps both limit the mycotoxins available to harm an animal and can potentially mitigate some of the damage caused. 

An in vitro trial done in Germany looked at the adsorption of ergot toxins using Trouw Nutrition’s Toxo products. At a pH of 6.5, 90.4% of the ergot extract was absorbed and at a pH of 3.0, 93.6% of the ergot extract was absorbed. 

A similar experiment explored the binding of emerging mycotoxins using the Toxo-XL product. In the trial, 1,000ppb sterigmatocystin, 1,000ppb enniatin B and 1,000ppb roquefortine C were exposed to 0.2% Toxo-XL at a pH of 3.0 or 6.5. In more neutral conditions, 74.9%, >85.0% and 83.1% of sterigmatocystin, enniatin B and roquefortine C, were adsorbed by the product, respectively, demonstrating the potential for a high adsorption of emerging mycotoxins in the GI tract. 

Conclusions 

The results and analyses demonstrate the importance not only of proper sampling but also the use of the right statistical parameter (median instead of means for concentrations) to minimize data variation between the samples and applying the LOD so that contamination percentages are not overestimated. Trouw Nutrition applies the LOD and LOQ precisely which is very critical for correct data interpretation.”

Looking at the analysis in terms of concentration, DON, FUM, T-2, ZEA, AF and OTA – are key concerns. Those results are based on analysis of samples using median concentrations rather than averages. 

In 2022, these data suggest a potential threat for piglets, dairy cows, sows, and poultry, in that order. However, more information is needed regarding aquaculture feeds and pet food and more research is needed into emerging mycotoxins.