- The impact of mycotoxins in poultry house is frequently underestimated.
- Sampling errors, misunderstanding or misinterpretation of lab results, subclinical effects and incomplete testing can all impact a mycotoxin risk assessment.
Although most producers are aware of the most common mycotoxins, many underestimate the potential impacts of mycotoxins on their flocks. From sampling errors to emerging mycotoxins to subclinical effects, here are some reasons that flocks might be at greater risk than you think.
Mycotoxins have the potential to have an outsized impact on a flock. Fortunately, most stakeholders in the poultry chain are aware of mycotoxins’ potential negative effects on production, immunity and gut health status in poultry, but the impact of mycotoxins in poultry houses is often underestimated.
Why Mycotoxins are Underestimated
1) Appearance is often subclinical
- There is no acute, direct, clear illness visible and, day-to-day it doesn’t look like there is a substantial negative impact in the flock.
- The life-span of broiler is too short for effects to manifest clinically. although the animal experiences negative impact internally.
- It is more difficult to counter vague subclinical issues in the flock. Therefore, it is easier to focus on clear clinical issues, potential pathogens or deviations in nutritional ration and attempt to put a finger on that which is more tangible.
- Periodic disease outbreaks in flocks are actually indirect symptoms of mycotoxin contamination, the latter being either the trigger or root cause for clinical disease.
Nevertheless, mycotoxins are one of the major contributors of huge financial losses in global animal (protein) production.
Figure 1. The difference between FCR (black line) in high and low contaminations of mycotoxins (colored lines) in broilers (Adapted from Kolawole et al., 2020).
An example of a realistic outcome comes from the recent data of Kolawole et al. (2020). In his long-term evaluation (18 successive trials) of a commercial farm, it was shown that natural contamination with levels below the EU recommendations for mycotoxins has a significant impact of 2.5 points in FCR (Figure 4), confirming the synergistic effects of the mycotoxins (fumonisins, zearalenone, DON and Diacetoxyscirpenol (DAS)) and the decreased broiler performance in commercial conditions.
2) Incomplete and incorrect mycotoxin testing
- For poultry, final feed consists of many feed ingredients. Testing a single ingredient such as wheat, barley or oats doesn’t give the full picture of the potential mycotoxin load in the final feed.
- Raw feed materials are tested on an ad hoc basis, rather than continuously, and the batches in between can be contaminated.
- An Elisa testing strip is only qualified for one specific feed matrix, e.g. wheat If it is used for corn or other feed ingredients, this will lead to huge test errors, potentially underestimating risks.
- Multiple factors affect how mycotoxins affect animals in the field, and—from a practical perspective—the limit of detection of tested mycotoxins may be set too high. This results in a ‘false negative’ for that feed stuff and species. Other factors include the feed intake of the tested feed stuff by the animal and the intrinsic toxicity of the mycotoxin.
- Though very prevalent mycotoxins (e.g., nivalenol, HT-2), emerging mycotoxins (e.g., moniliformin, beauvericin, alternariol) and masked mycotoxins (e.g., deoxynivalenol-3-glucoside) can have high contamination levels in raw feed materials, they are often not included in standard tests, In spite of this, they can heavily contribute to the total mycotoxin load of feed compounds.
- Particularly in the group of trichothecenes A, T-2 but also HT-2, are prevalent. Both have an even higher intrinsic toxicity than trichothecenes B, but are often not included in tests (especially HT-2). (Figure 2)
Figure 2. Prevalence of trichothecenes A in Finished Feed poultry (FFp) measured with the multi-mycotoxin method Spectrum 380® offered by BIOMIN® (data from 2018- June 2021: Global FFp sample number = 273; European FFp sample number = 99). Besides T-2 toxin often HT-2 is prevalent, both having a high intrinsic toxicity.
3) Feed sampling errors
- Distribution of mycotoxins is unequal in all raw feed materials. There is often ‘hot-spots’ distribution, therefore sampling errors are one of the major reasons for inaccurate results in mycotoxin lab tests.
Samples should be well distributed throughout the raw feed material bunker. A minimum of 10 subsamples should be taken and mixed into one large sample, and/or feed samples should be taken over a longer time period (e.g. over five days, daily from several spots across the total feedline). (Figure 3)
Figure 3. Steps for a successful sampling procedure
4) Incorrect interpretation of lab results
- Multiple mycotoxins are often found in a sample, and interaction between mycotoxins can lead to increased risk of toxicity for poultry due to synergistic effects (e.g. FUM & DON, ZEA & DON, AFLA, T2, etc.).
- While six mycotoxins are most well-known (FUM, DON, ZEA, T2, OTA, AFLA) other mycotoxins can contaminate feed ingredients as well. Contamination with masked and emerging mycotoxins (Figure 4) is also common, and present risks for animal health. For example, in the Netherlands, whole plant corn silage has contained high loads and the prevalence of NIV and masked mycotoxin DON-3-Glucoside were observed (Table 1).
- Even low levels of (multiple) mycotoxins canbe harmful, creating a subclinical negative impact and synergistic effects (Figure 1). The higher threshold levels of the FDA or EU do not take into account long term exposure, synergistic interaction and subclinical negative impact of mycotoxins in poultry
- Other sources of mycotoxins are overlooked and should be added to the total oral load of the flock (e.g. by-products, straw/bedding, loose grains).
- Result ‘Not-Detected (n.d.)’, does not mean that there is no mycotoxin contamination, only that the concentration was below the limit of detection. If the limit of detection for a commodity is high (often occurring in more rapid and cheaper tests), one can overlook potential harmful mycotoxins in a feed sample.
- In samples with high moisture content, mycotoxin concentrations are lower because they are diluted and therefore need to be recalculated to represent the percentage of moisture content of the finished feed which is fed (e.g. 88% dry matter).
Figure 4. Data is presented for European corn samples analysed with Spectrum Top®50, offered by BIOMIN®, 2018 to June 2021 (sample number = 190). All metabolites with >5% prevalence is shown. Although the well-known fumonisins, deoxynivalenol and zearalenone are most prevalent, also emerging mycotoxins (in blue) are highly frequent (e.g. Moniliformin, Enniatin B, Beauvericin) as well as masked mycotoxins (in red, here: deoxynivalenol-3-glucoside). Less well-known mycotoxins as HT-2 toxin and Nivalenol are also present and add up to the overall risk for animal health due to contamination with trichothecenes.
|Total samples: 62||Trichothecene B**||DON||NIV||DON-3-Gluc||HT-2||ZEA|
* samples were only tested for DON, NIV, DON-3-Gluc, ZEA and HT-2 via LC-MS/MS method
** is the total sum of DON+NIV+DON-3-Gluc
Very sensitive multi-mycotoxin analysis methods such as Spectrum Top®50 and Spectrum 380®, both based on LC-MS/MS, help to increase our knowledge of the occurrence of various mycotoxins in feed ingredients or final feed for poultry. They are also a valuable tool available for customers to get a comprehensive overview on the mycotoxin load in their feed samples.
Although significant advances in efficiency and disease management and prevention have been made in poultry production, in productive flocks there is still room for improvement in managing subclinical risks. Most stakeholders in the poultry chain know that mycotoxins can impair the production and health status of flocks. Still, subclinical appearance of mycotoxin contamination, challenges of proper testing and difficulty interpreting laboratory results often lead to underestimation of the impact of mycotoxins, and acute, subclinical and impactful production and health events in poultry are not always correctly linked to mycotoxins as a root cause.
Considering potential reasons that the negative impact of mycotoxins are frequently underestimated, will enable the poultry chain to reach birds’ potential. Improvement of production efficiency and health status also contributes to increased sustainability in poultry production. This makes the poultry chain an even more important and sustainable, high quality, protein source to feed the world.