Mycocheck Survey 14 INTRODUCTION Mycotoxins are secondary metabolites produced by moulds that have the capacity to impair animal health and productivity. Contamination of forages and cereals with mycotoxins can, therefore, occur in the field following infection of plants with particular pathogenic fungi but also post-harvesting during storage of feed ingredients and finished feed whenever environmental conditions are appropriate for spoilage fungi. Typical mycotoxins associated with contamination in the field are those produced by Fusarium mould spp. These include the Trichothecene toxins, Deoxynivalenol (DON), T2 & HT2, which are toxic to epithelial cells in the gastro-intestinal tract and affect impair nutrient absorption, reduce feed intakes and weight gain. If absorbed into the blood stream they can also modulate the immune system reducing resistance to disease. Zearalenone is another Fusarium mycotoxin of particular concern to animal production due to its ability to mimic oestrogen and negatively impair reproduction. Fumonisins, meanwhile, are specifically associated with pulmonary odema in pigs but also more generally cause liver and kidney toxicity and disrupt cellular processes. Aspergillus and Penicillium spp moulds are associated with storage conditions and can also produce range of mycotoxins including Aflatoxins, Ochratoxin A & Patulin. Aflatoxin is a concern in dairy production due to its conversion to Aflatoxin M1 in milk and subsequent carcinogenicity to humans. Ochratoxin A is established as toxic to the kidneys but also has liver and carcinogenic properties. Patulin are associated with immunological, neurological and gastrointestinal outcomes in animals. One of the main challenges with mycotoxins in animal production is diagnosis as the symptoms are typically vague and non-specific. Producers need to be aware of the issues as chronic exposure can become costly in the long-term. Analysing feed for mycotoxins should form part of routine onfarm risk assessment for myocotxins. Micron Bio-Systems analyses feed samples for 13 major mycotoxins using LC-MS/MS technology with their Mycocheck service. The following report summarises mycotoxin contamination levels in feedstuffs received for testing in 14. MATERIALS & METHODS All samples received during 14 were analysed by LC-MS/MS for the following 13 mycotoxins: Aflatoxin B1, B2, G1, & G2, Ochratoxin A, Patulin, Sporidesmin A, Fumonisin B1 & B2, Zearalenone (ZON), Deoxynivalenol, T2 & HT2. The limits of detection for each mycotoxin is outlined in Table 1.
Table 1: Limits of detection for each mycotoxin analysed with Mycocheck Mycotoxin Detection Limit (ppb) Aflatoxin B1.2 Aflatoxin B2.2 Aflatoxin G1.2 Alfatoxin G2.2 Deoxynivalenol (DON) 1. Fumonisin B1 (FB1) 1. Fumonisin B2 (FB2) 1. HT2 1. Ochratoxin A.2 Patulin 1. Sporidesmin A 1. T2 Toxim 1. Zearalenone (ZON) 1 RESULTS Number and types of samples received In 14 Micron Bio-Systems received over 2 samples of feed and feed ingredients for mycotoxin analysis by LC-MS/MS from across the UK, Europe and North Africa. Samples received included TMR, silage, compound feed, by-products and grains and were all analysed for Alfatoxin B1, B2, G1, G2, Ochratoxin A, Patulin, Sporidesmin A, Deoxynivalenol (DON), Zearalenone (ZON), Fumoninsin B1 & B2, T2 & HT2. Table 2 summarises the number of each sample type received and the percentage of samples where mycotoxins were detected. Table 2: Number of each sample type received and percentage of samples where mycotoxins were detected Feed type No. Samples samples where mycotoxins were detected TMR 66 72 Silage (excluding grass) 52 Silage (including grass) 17 29 Compound feed 35 97 Miscellaneous 8 1 Grains 26 69 Sporidesmin A and Patulin were not detected in any samples received. Aflatoxin mycotoxins were only detected two samples (maize & maize gluten) at levels of 27ppb and 8 ppb respectively whilst Ochratoxin A was detected in three samples (maize gluten, biscuit meal and a grain sample) again at low levels (<3ppb). No mycotoxins were detected in grass silages. Mycotoxins produced by Fusarium moulds (DON, ZON, Fumoninsins, T2 & HT2) were much more prevalent in samples. Figure 1 details the percentage of samples testing positive for these mycotoxins by feed type.
Mycotoxins in TMR samples DON was detected more frequently than any other toxin but also at the highest levels in TMR samples (Figures 1 & 2). 7 3 1 ppb 3 3 2 1 1 Figure 1: TMR samples testing positive for mycotoxins Figure 2: Average ppb of TMR samples testing positive for mycotoxins Taking account of the total mycotoxin load 56 of TMR samples contained low level contamination (<pbb), were classed as posing a medium risk (-ppb) and 24 containing high levels of mycotoxins (>pbb) (Figure 3). 24 56 < ppb - ppb > ppb Figure 3: Proportion of TMR samples categorised as low risk (<ppb), medium risk (<-ppb) and high risk (>ppb) according their total mycotoxin load
Mycotoxins in silage samples (excluding grass) Again DON was the most prevalent mycotoxin in silage samples and also detected at the highest levels (Figures 4 & 5). 7 7 3 3 1 1 Figure 4: silage samples testing positive for mycotoxins Figure 5: Average ppb of silage samples testing positive for mycotoxins Similar to TMR samples the total mycotoxin load of 56 of silage samples was less than pbb, 23 were classed as posing a medium risk (-ppb) and 21 containing high levels of mycotoxins (>pbb) (Figure 6). 21 23 56 < ppb - ppb > ppb Figure 6: Proportion of silage samples categorised as low risk (<ppb), medium risk (<-ppb) and high risk (>ppb) according their total mycotoxin load
Compound feeds DON was present in 97 of compound feed samples tested but ZON and the Fumonisins were also highly prevalent detected in 83 and 8 of samples respectively (Figure 7). On average DON was also detected at the highest levels (>pbb). On average ZON, Fumonisin, T2 & HT2 were present at lower levels in contaminated samples (Figure 8). 1 1 8 ppb 9 8 7 3 1 Figure 7: Compound feed samples testing positive for mycotoxins Figure 8: Average ppb of compound feed samples testing positive for mycotoxins The total mycotoxin load in 57 of the compound feed samples tested was above ppb and therefore classified as high risk. 23 samples had medium risk total mycotoxin load (-ppb) with only with total levels under ppb (Figure 9). Many of the compound feed samples surveyed originated from southern Europe and so these high levels were not surprising given the climatic conditions experienced in the summer of 14 during harvest in this region. 57 23 < ppb - ppb > ppb Figure 9: Proportion of compound samples categorised as low risk (<ppb), medium risk (<-ppb) and high risk (>ppb) according their total mycotoxin load
Cereal grains DON was the most prevalent mycotoxin detected in grain samples and was also detected at the highest levels (Figures 1 & 11). DON was detected in a number of samples from Southern and Central Europe above ppb. 3 ppb 1 1 1 Figure 1: Cereal grains samples testing positive for mycotoxins Figure 11: Average ppb of cereal grains samples testing positive for mycotoxins The total mycotoxin load in 46 of cereal grain samples was below ppb and therefore considered low risk. However in 42 of samples the total mycotoxin load was above pbb and could be conceived as being high risk (Figure 12). These were the samples that originated from Central and Southern Europe with high levels of DON. 42 46 12 < ppb - ppb > ppb Figure 12: Proportion of compound feed samples categorised as low risk (<ppb), medium risk (<- ppb) and high risk (>ppb) according their total mycotoxin load
Miscellaneous This category included feed ingredients such as DDGS and biscuit meal. DON was detected in all samples but ZON and Fumonisins were also present in the majority of samples (Figure 13). DON was present at the highest level, on average 3ppb, followed by Fumonisin with an average level of 3 ppb (Figure 14). 1 9 8 7 3 3 2 ppb 3 1 1 1 Figure 13: Cereal grains samples testing positive for mycotoxins Figure 14: Average ppb of cereal grains samples testing positive for mycotoxins Over 62 of these samples tested had a total mycotoxin load above ppb. 25 of samples were categorised as medium risk with a total mycotoxin load of 25 whilst only 12 of the samples had a total mycotoxin load of 12.5 and were considered low risk (Figure 15). 12.5 25 62.5 < ppb - ppb > ppb Figure 15: Proportion of miscellaneous feed ingredient samples categorised as low risk (<ppb), medium risk (<-ppb) and high risk (>ppb) according their total mycotoxin load
CONCLUSIONS The majority of mycotoxin contamination in animal feed originates from fungal growth on crops prior to harvest and is subject to prevailing environmental conditions. This is evident from Micron Bio-Systems 14 Mycocheck survey. Only Fusarium mycotoxins, DON, ZON, Fumonisins, T2 and HT2 were detected in complete feeds, cereal grains and forages. Storage mycotoxins such as Aflatoxin and Ochratoxin were only present in a handful of samples and at extremely low levels suggesting the risk to animal health from these mycotoxins is limited. Of the Fusarium mycotoxins, DON was present in a higher proportion of samples and at higher levels regardless of the sample type. On its own DON is toxic to epithelial cells linings the gastrointestinal tract and can therefore reduce nutrient absorption, feed intakes and efficiency. However, certain combinations of mycotoxins can exert synergistic toxic effects on the animals and so it is important to consider the total mycotoxin load. A higher proportion of compound feed samples, cereal grains and by-products had total mycotoxin loads over ppb. Several of these samples originated from Southern and Central Europe, where the harvest was severely affected by heavy rainfall. Although silages and TMR had a lower proportion of samples which high total mycotoxin loads, ruminant producers should remember these feeds are consumed in much greater volume compared to the cereal grains and compound feeds. In summary, the results of the 14 Mycocheck survey demonstrate that producers should not overlook the risk from mycotoxins. They should consider all the potential sources of mycotoxin contamination and if any doubt about any material get it analysed with Mycocheck.