Occurrence of Mycotoxins in Feed Samples from Asia

The last report on the occurrence of mycotoxin was published in 2006 (1), generated immense interest among the feed industry.

In the current analysis, the occurrence of various mycotoxins in feed samples was found to be: aflatoxin total; 16%, deoxynivalenol; 48%, fumonisin B1; 46%, ochratoxin A; 24% and zearalenone; 38%. The general outlook was similar to that reported early on as depicted in Chart 1.


The data

This report is based on about 800 samples analyzed over a 12-month period from October 2005 to September 2006 for the major mycotoxins of interest; namely, aflatoxins total, zearalenone (ZON), deoxynivalenol (DON), fumonisin B1 (Fum), T-2 toxin and ochratoxin A (OTA). The samples received were primarily from Asia. Again, the data were analyzed from two perspectives; first by geographical regions where the samples were originally from, and second by means of commodity types. The geographical regions are grouped as follows; North Asia (China, Japan, Korea and Taiwan), South-East Asia (Indonesia, Malaysia, the Philippines, Thailand and Vietnam), South Asia (primarily India) and Oceania (primarily Australia). The sample types are classified as feed ingredients (such as corn, soybean meal, wheat, rice, DDGS, etc.) and finished feed samples.


The Results

For the purpose of data analysis, non-detect levels are based on the detection limits of the test method for each toxin; Aflatoxins total < 4 µg/kg; Zearalenone < 32 µg/kg; Deoxynivalenol < 50 µg/kg; Fumonisin B1 < 100 µg/kg; T-2 Toxin < 125 µg/kg and Ochratoxin A < 2 µg/kg. High Performance Liquid Chromatography (HPLC) methodology was used for the analysis of all mycotoxin except T-2 Toxin which was performed using Thin Layer Chromatography (TLC).


Chart 1: Occurrence of Mycotoxin in all feed samples monitored from (a) Oct 2003 to Sep 2005 and (b) Oct 2005 to Sep 2006

The occurrence and concentration of mycotoxin in all feed samples analyzed according to the geographical regions are depicted in Tables 1A - D below.

Chart 2. Prevalence of Mycotoxin in different geographical regions within Asia-Pacific.





North Asia:

Occurrence of mycotoxins in samples received from North Asia was 6%, 55% 75% 58% and 28% for aflatoxins, zearalenone, deoxynivalenol, fumonisin B1 and ochratoxin A respectively. T2- toxin was found in less than 1% of the total sample population. For aflatoxin, the highest level detected was 494 ppb in a corn sample from China. DON was prevalent in this region (75%) and the highest level detected was in a DDGS sample from China with 10,374 µg/kg. ZON and Fum, on the other hand, were found in 55% and 58% of the samples respectively. Highest level of ZON found was 14,105 µg/kg in a corn gluten meal sample from China. For fumonisin B1, it was 14,714 µg/kg in a corn sample also from China. Ochratoxin A was detected in 28% of the samples; 82 µg/kg in a soybean meal sample from China was the maximum level analyzed.


South-East Asia:

The prevalence of mycotoxin contamination in South-East Asia is in the order as follows; fumonisin (45%), aflatoxin (40%), zearalenone (23%), deoxynivalenol (19%) and ochratoxin (9%).T-2 toxin was not detected in the current analysis.


South Asia:

Although the number of samples analyzed from this region was comparatively smaller (total 31), prevalence of aflatoxin (55%) was evident. Occurrence of ZON and Fum were observed at 19% and 29% respectively. OTA though was found in 57% of the samples, the levels detected were not high (maximum of 10 µg/kg). DON was found in less than 1% of the samples and T-2 toxin was not detected in any of the samples analyzed.


Oceania:

More than half of the samples analyzed were straws/hay. The prevalence of mycotoxins from this region was DON (16%), ZON (15%), Fum (8%) and aflatoxins (3%). OTA and T-2 toxin were not detected in these samples.

Tables 2A – 2I below are intended to show the occurrence of the various mycotoxins in the feed samples according to the commodity type.

Chart 3. Prevalence of mycotoxins in different commodities





Corn:

About 180 corn samples were analyzed in the current report. Among the six major mycotoxins analyzed, except for T-2 toxin, the remaining 5 toxins were present in 20 to 81% of the corn samples. Aflatoxins were found in 20% (high of 494 µg/kg; average 72 µg/kg), ZON 47% (maximum of 3,510 µg/kg; average of 404 µg/kg), DON 72% (maximum of 5,270 µg/kg; average of 862 µg/kg), Fumonisin B1 81% (maximum of 14,714 µg/kg; average 1,716 µg/kg), and OTA 18% (maximum of 44 µg/kg; average 11 µg/kg).


Soybean Meal:

Of the 80 soybean meal samples analyzed, occurrence and concentration of mycotoxin contamination were relatively low except for ZON. Aflatoxins were found in 1% (only one sample was found at 5 µg/kg); ZON in 26% (maximum of 1,078 µg/kg; average of 273 µg/kg); DON in 10% (maximum of 489 µg/kg; average of 278 µg/kg), Fumonisin B1 8 % (maximum of 265 µg/kg; average of 180 µg/kg) and T-2 toxin 1% (only one out of 77 samples was contaminated at 133 µg/kg). For OTA, 30% were positive (maximum of 82 µg/kg; average 19 µg/kg).


Wheat/bran:

More than 40 wheat/bran samples were analyzed. No aflatoxins were found in all wheat/bran samples tested. DON accounted for 79% of the contamination (maximum of 3,908 µg/kg; average 505 µg/kg). ZON was found in 26% of the samples (maximum of 1,835 µg/kg; average 273 µg/kg). Eight out of 14 wheat/bran samples (57%) were positive (maximum of 23 µg/kg; average 8 µg/kg).


Corn Gluten Meal:

The corn gluten meal samples analyzed show widespread prevalence for ZON with 89% (maximum of 14,105 µg/kg; average of 2,082 µg/kg) and Fum with 50% (maximum of 12,027 µg/kg, average 2,285 µg/kg). DON accounted for 32% (maximum of 10,259 µg/kg; average 1,890 µg/kg) and aflatoxins 16% (maximum of 82 µg/kg, average 37 µg/kg). Both OTA and T-2 toxin were not detected in the corn gluten meal samples.


Distiller Dried Grain Soluble (DDGS):

The use of DDGS as feed ingredient is gaining popularity within the region. Like corn gluten meal samples, the prevalence of ZON, DON and FUM is evident. ZON accounted for 88% (high of 8,107 µg/kg; average 1,260 µg/kg); DON 65% (high of 10,374 µg/kg; average 3,075 µg/kg) and Fum 64% (high of 9,042 µg/kg; average 1,718 µg/kg). Aflatoxin was found in 25% of the samples (maximum 89 µg/kg; average 27 µg/kg). All 3 samples tested for OTA were positive (maximum 68 µg/kg; average 38 µg/kg). T-2 Toxin was not detected.


Rice:

25% were found to be contaminated with aflatoxins (maximum of 37 µg/kg; average 19 µg/kg). Though ZON was also found in 25% of the samples, the contamination level was relatively low (maximum 56 µg/kg; average 50 µg/kg). Only 6% were positive for Fum (only one sample detected at 278 µg/kg). DON, OTA and T-2 toxin were not detected.


Finished Feed:

Finished feed comprises mainly poultry and swine feed samples. The order of occurrence was found to be as follows: Fum 58% (maximum 4,909 µg/kg; average 702 µg/kg); DON 47 % (maximum 3,003 µg/kg; average 389 µg/kg); ZON 37% (maximum 5,214 µg/kg; average of 369 µg/kg); OTA 24% (maximum 59 µg/kg; average 9 µg/kg); aflatoxin 22% (maximum 139 µg/kg; average 23 µg/kg) and finally T-2 toxin accounted for less than 1% of contaminated samples (maximum 399 µg/kg; average of 266 µg/kg).


Straw/Hay:

More than 40 straw/hay samples were analyzed. Predominantly, DON and ZON were found at 47% (high of 1,484 µg/kg; average 352 µg/kg) and 28% (high of 758 µg/kg; 170 µg/kg) respectively. Only 5 % were positive for Fum (high and average of around 300 µg/kg). Aflatoxin and T-2 toxin were not detected.



Summary:

The occurrence and highest levels of mycotoxins detected based on commodity type and country of origin is summarized in the table below:

Interestingly, from the cumulative data we have seen, there were certain degree of association between some mycotoxins and specific commodity types. For instance, in corn, 81% were found to be contaminated with Fum B1; for wheat/bran, DON was found in 79% of the samples; for corn gluten meal and DDGS, ZON accounted for more than 88% of the contamination.

Nevertheless, the data presented are intended for information purposes only. For detailed profile of mycotoxin contamination in various commodities, it is advisable to carry out the necessary analyses. Such valuable information shall then be incorporated into the total quality management system for the betterment of animal health.


Outlook:

Special interest in the new study will be new raw materials such as DDGS, Cassava and the like. The budget for this study is about 250 000 USD. For more information please contact Kurt Wegleitner (Marketing Director), Biomin Laboratory Singapore Pte Ltd.


Footnote:

As an indication on the cost of such survey conducted by Biomin Laboratory Singapore Pte Ltd, the charges are based on each toxin per sample. The analytical fees range from US$ 70 – 95 per toxin per sample depending on the toxin requested.


Reference:

(1) LJ Chin and LM Tan, 2006. Occurrence of mycotoxins in Asian feed samples. Asian Poultry (May 2006) and Asian Pork (June 2006).