Biomin Survey 2010: Mycotoxins inseparable from animal commodities and feed

The acknowledgement of mycotoxins as a major hindrance to animal productivity and health has increased over the past few years. Much research work has been conducted and published on the effects of these toxic fungal metabolites in different aspects of animal physiology and husbandry.

Regarding the occurrence of mycotoxins however, the work which is published focuses more often than not on food intended for human consumption, on a certain country or region, or on a certain commodity, and usually the amount of samples tested is too small to allow generalisations.

In 2005 and in order to overcome this gap of information, Biomin started a mycotoxin survey program which nowadays is able to provide a good overview on the worldwide occurrence of mycotoxins. This work focuses specifically on the results between January 2010 and December 2010, inclusive.

Mycotoxin analyses were outsourced and a total of 3,349 samples were tested. In total 11,195 analyses were carried out for the most important mycotoxins in terms of agriculture and animal production – aflatoxins (Afla), zearalenone (ZON), deoxynivalenol (DON), fumonisins (FUM) and ochratoxin A (OTA).The majority of the analyses were performed at Romer Labs Diagnostic in Austria, Romer Labs Singapore, Romer Labs Inc in the US and Samitec in Brazil. 70% of the samples were analysed by High Performance Liquid Chromatography (HPLC), 30% by Enzyme Linked Immunosorbent Assay (ELISA) (only applied in the European and North America lab) and around 9% of the samples were submitted to thin-layer chromatography (TLC) method (only North American samples). For the purpose of data analysis, non-detection levels are based on the quantification limits of the test method for each mycotoxin. For more details regarding the analytical procedure, please contact the authors.

Overall results
As can be seen in Figure 1, from all survey samples 28%, 42%, 58%, 55% and 26% tested positive for contamination with Afla, ZON, DON, FUM and OTA, respectively. If compared with data from the previous year 2009, an increase on the occurrence of the fusariotoxins ZON and DON can be detected. In addition to higher occurrence level also incredibly high maximum levels for the toxins ZON, DON and FUM were found this year (see Table 1) in comparison to the last year. Average contamination levels of all samples tested for ZON and DON increased also to 108 (2009: 77 ppb) and 722 ppb (418 ppb), respectively.

Interesting differences were obtained for the different regions (Table 2, from 2a to 2j). In north Asia, the most prevalent mycotoxins are the ones produced by Fusarium fungi, namely ZON, DON and FUM. DON was present in 71% of tested samples in an average of 757 ppb. In south east Asia, the most prevalent mycotoxin was aflatoxin, present in 65% of analysed samples at an average level of 22 ppb. FUM and ZON were present in 57% and 49% of tested samples, at an average of 493 ppb and 55 ppb, respectively.

Generally regarded as storage mycotoxins, Afla and OTA are the most prevalent in countries such as India, Pakistan and Bangladesh where 88% and 71% of analysed samples tested positive for these mycotoxins, respectively. Nonetheless, the importance of fusariotoxins in this region must not be disregarded, as FUM, DON and ZON were shown to be present in 58%, 30% and 30% of samples. Within the Asia-Pacific region, Australia and New Zealand show a different mycotoxin pattern, with oftentimes a lower prevalence of mycotoxins when in comparison with neighbour countries.

US had a problem
North America’s concern with mycotoxins such as DON and ZON is widely known, especially after last year’s crops. DON was present in 87% of tested samples at worrying average levels (1,487 ppb). In South American samples, which are mostly coming from Brazil, the trend was clear, with fumonisins as the biggest contaminant (88% positive samples) and at incredibly high average levels (2,515 ppb). ZON was also found to be very prevalent (57% positive samples; average 129 ppb). In Europe, the situation is distinct depending on the latitude. If in northern Europe DON is the most prevalent mycotoxin (62% positive), at lower latitudes (nearer the equator), mycotoxins such as Afla have greater importance. It is important to point out the great incidence and high averages of DON in north and central Europe and of DON and FUM in south Europe.

From all samples tested positive for DON in central European regions, an average contamination as high as 967 ppb was analysed. Also from this region, the highest DON level of the whole survey was registered in a wheat sample from Austria.

In Middle East, FUM were the most prevalent mycotoxins (65% positive samples), followed by DON (40%) and ZON (29%). As this year only one sample from Africa was analysed, no conclusion can be drawn from this region.

Corn by products danger
Regarding commodities (Table 3), corn was the most widely tested commodity. FUM and DON were found to be the mycotoxins of higher prevalence with 75% and 72% of positive samples and 1,912 ppb and 956 ppb average levels, respectively. As expected, corn by-products such as corn gluten meal and DDGS presented very high levels of fusariotoxins such as ZON, DON and FUM, a situation which must be taken into account when using such commodities in animal diets.

In comparison with corn and corn by-products, ingredients such as soybean and soybean meal, wheat and wheat bran, rice, rice bran and barley were in general, less contaminated. Attention must be paid to DON’s presence in wheat, wheat bran and barley and to ZON levels in rice and rice bran. Moreover, as anticipated due to the ensiling process, aflatoxins are not a major contaminant of silages. In opposition, DON, ZON and FUM originated in this commodity must be considered when mycotoxins in ruminants’ diets are concerned. Finally, and regarding finished feed, almost all samples tested were positive for at least one mycotoxin (only 14% were negative for all tested mycotoxins, data not shown). FUM was present in 69% of tested samples followed by DON (58%), ZON (57%), Afla (46%) and OTA (39%). Average levels found were quite high, especially when one realises they will be fed to animals without further dilution.

Conclusion
All in all, the results of this survey present a clear conclusion: Mycotoxins are, more frequently than not, present in animal commodities and feed. Out of the more than 3,300 samples tested during the 12-months period of 2010, only 22% of them were negative for mycotoxin presence. 36% of tested samples were positive for at least one tested mycotoxin and 42% were contaminated with two or more mycotoxins (Figure 3).

This ubiquitous presence of mycotoxins in animal diets represents a serious risk to animals’ performance and health. The acknowledgement of mycotoxins in commodities is part of risk assessment and the first step for a proper mycotoxin risk management.

Biomin research proves there is no single method for effective mycotoxin prevention. Most grains are afflicted by a wide variety of mycotoxin types, and not all varieties of mycotoxins can be destroyed with one deactivation agent. Years of research prove that the best way to deactivate mycotoxins is with a triple assault – adsorption, biotransformation and bioprotection. Combined, these three modes of action provide the most thorough means of deactivating the toxic effects of mycotoxins.