Mycotoxins are recognized for their effects on animal health and productivity. However, diagnosis of mycotoxin-induced disorders is often tricky as many mycotoxicoses present with non-specific signs that could be attributed to a variety of causes. Screening feeds for the presence of mycotoxins is the most widely accepted approach to monitor mycotoxin exposure and gauge potential risk in livestock consuming those feeds. However, limitations exist with feed testing including the fact that by the time challenges are identified in the herd or flock, the contaminated feed that contributed to issues may already be gone. Furthermore, mycotoxins are not evenly distributed in feeds, but rather occur in “hotspots” and this non-homogenous nature of mycotoxins complicates sampling and analysis of these naturally occurring fungal metabolites. Furthermore, these toxins occur in low concentrations (parts per million (ppm) and parts per billion (ppb)) which further confounds detection and can lead to inconclusive results.
An alternative approach to feed analysis of mycotoxins is the application of mycotoxin biomarkers – assessing mycotoxin exposure directly in the animal by analyzing blood or other body fluids and tissues. Innovation driven by advances in analytical techniques has improved these capabilities in scientific settings, leading to interest in biomarker assessment at the farm level. Despite its potential, in-field application of mycotoxin biomarkers still has major limitations. Currently, it is difficult to interpret biomarkers results for a variety of reasons, plus most of these types of analyses are not available commercially, so access to testing is very limited.
Although there are many, some of the key challenges to on-farm implementation of mycotoxin biomarkers analysis include:
(1) timing of sampling – there are considerable differences in kinetic profiles, e.g,. the extent to which toxins are absorbed, metabolized, and eliminated from the body which is further complicated by timing of consumption of contaminated feed.
(2) species-dependent differences in mycotoxin metabolism complicates which biomarkers to screen for in what matrix (blood, urine, feces, etc.).
(3) unknowns in the field including variation across and among different groups of animals due to age, gender, production stage, etc. – there are many factors which confound an animal’s response to mycotoxin exposure, complicating risk assessment and prediction of outcomes following mycotoxin consumption both within herds and between herds.
(4) variability in laboratory experience – these analyses are done on complex matrixes which are difficult to handle and analysis is further complicated by the fact that most biomarkers of interest occur in extremely low concentrations (parts per trillion, ppt).
(5) current lack of biomarker reference values – in the lab: in contrast to mycotoxin analysis in feed, no reference materials or proficiency tests exist for the evaluation of mycotoxin biomarker methods; in the field: research has failed to correlate levels of exposure-based biomarkers to clinical signs or the severity of mycotoxicosis, so no established thresholds exist for interpreting what level(s) of biomarkers mean.
Analytical methods for the assessment of mycotoxin biomarkers are becoming more time- and cost-effective. However, various limitations hinder the practicality of this type of testing in field settings. As more is learned through scientific studies and interpretation thresholds are established, it is hopeful that the future will offer application of mycotoxin biomarkers at the farm level.
To learn more about mycotoxin biomarkers and the current limitations of this type of testing on-farm, please visit:
18 April 2022
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