Prevalence of mycotoxins in aquafeed ingredients: an update


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Over recent years several factors have led to an escalation of feed ingredient prices especially fishmeal. As a consequence, alternative commodities have been used, mainly plant protein sources. However, as a result of this trend, aquaculture feeds have a higher risk of being contaminated with mycotoxins.

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Prevalence of mycotoxins in aquafeed ingredients: an update

  1. 1. I N C O R P O R AT I N G f i s h far m ing t e c h no l og y November | December 2013 Prevalence of mycotoxins in aquafeed ingredients: an update International Aquafeed is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058 The International magazine for the aquaculture feed industry
  2. 2. FEATURE Prevalence of mycotoxins in aquafeed ingredients: an update by Gonçalo Santos, technical manager - Aquaculture, Biomin Holding, Austria, Karin Naehrer, Product manager, Biomin Holding, Austria and Pedro Encarnacao, business development director, Biomin Singapore, Singapore O ver recent years several factors have led to an escalation of feed ingredient prices especially fishmeal. As a consequence, alternative commodities have been used, mainly plant protein sources. However, as a result of this trend, aquaculture feeds have a higher risk of being contaminated with mycotoxins. The effects of mycotoxins are in general associated with reduced growth and health status of fish, shrimp and other farmed animals. The most prevalent fungi responsible for the occurrence of mycotoxins are Aspergillus, Penicillium and Fusarium sp. At the moment more than 400 different mycotoxins have been reported that can be clustered into five major classes: aflatoxins, ochratoxins, fumonisins, zearalenone and trichothecenes (CAST 2003). Mycotoxin contamination of aquafeeds occurs especially in countries with humid tropical climates owing to many factors, among which are permissive climatic conditions to mould growth and inappropriate methods of feed processing and storage. Despite this, the international trade of commodities makes it likely that contaminated products are imported in countries where traditionally tropical mycotoxins would not occur. Furthermore, due to the rising prices of feedstuffs feed manufacturers are looking for more economical raw materials to avoid increasing feed prices. The use of more affordable raw materials of lower quality might increase the risk of mycotoxin contamination in the feeds. For example, DDGS is an economical source of energy and protein that can be used in animal feeds, but reports show that is highly contaminated with multiple mycotoxins (Rodrigues, 2012). In contrast to terrestrial animals, in aquatic species, the absence of clear clinical signs that can be attributed to mycotoxicoses kept this topic away from the headlines. However, in recent years, the awareness Figure 1: Occurrence of mycotoxins worldwide Figure 2: Co-occurrence of mycotoxins in analysed samples 14 | INterNatIoNal AquAFeed | November-December 2013
  3. 3. FEATURE table 1: Soybean meal Soybean meal afla Zen Don FUM ota number of tests 71 62 65 69 61 Percentage of positive (%) 18 19 14 6 Co-occurance 26 average (µg/kg) 0 4 25 22 1 3.4 65.3 840 866 11.7 Corn afla Zen Don FUM ota number of tests 746 734 772 712 532 Maximum (µg/kg) table 2: Corn Percentage of positive (%) 25 43 64 86 10 average (µg/kg) 10 160 668 1,666 1 Maximum (µg/kg) 818 6,320 30,200 42,120 169.7 Corn gluten afla Zen Don FUM ota number of tests 41 42 44 41 31 Percentage of positive (%) 32 86 95 90 81 32 1,096 3,049 2,559 9 1,224 9,854 15,408 13,456 Co-occurance 103 table 3: Corn gluten average (µg/kg) Maximum (µg/kg) of mycotoxin-related issues within the aqua industry has grown, supported by increasing scientific evidence of the negative impact of mycotoxins in aquatic species and by frequent reports on the prevalence of mycotoxins in many raw materials. It is very difficult to guarantee the absence of mycotoxins in aquaculture feeds even when appropriate measures are taken, such as good screening programmes, selection of high quality raw materials and feed ingredients and good storage conditions. Co-occurance Therefore, it is urgent to find suitable ways to face the problem through an effective management of the risks posed by mycotoxin contaminations. In general, the effects of mycotoxins are associated with reduced growth and health take a CLOSER LOOK at Novus Aquaculture Our success in developing sustainable solutions evolves from a hands-on knowledge and understanding of the global aqua industry. By focusing on the needs of the animals, our team of experts will design a solution for your operation. FEED COST REDUCTION | HEALTH THROUGH NUTRITION | OPTIMIZED RAW MATERIALS | FUNCTIONAL FEEDS | SUSTAINABLE PRACTICES ® is a trademark of Novus International, Inc., and is registered in the United States and other countries. TM SOLUTIONS SERVICE SUSTAINABILITY is a trademark of Novus International, Inc. ©2012 Novus International, Inc. All rights reserved. 2978 November-December 2013 | INterNatIoNal AquAFeed | 15
  4. 4. FEATURE An overview of the occurrence of mycotoxins worldwide is presented in Figure 1. It can be noted that aflatoxins are more prevalent in tropical and temperate regions compared to cold climates. However, the distribution is also related to the different commodities. Moreover, it was possible to verify that the occurrence of more than one mycotoxin represented 50 percent of the tested samples and only 18 percent were negative for mycotoxin presence (Figure 2). This means that in field conditions the presence of more than one mycotoxin is the reason for synergistic effects and thus, even at low mycotoxin concentration levels it is possible to verify a great negative impact on the performance and health of animals. Contamination by commodity status of fish and other farmed animals. In terrestrial animals the toxic effects of mycotoxins are well known and can be of different nature such as carcinogenic (e.g. aflatoxins, ochratoxin A, fumonisins), estrogenic (zearalenone), neurotoxic (fumonisins), nephrotoxic (ochratoxin A), dermatoxic (trichothecenes) or immunosuppressive (e.g. aflatoxin B1, fumonisins and trichothecenes). Determining mycotoxins in aquafeeds As there are serious impacts of mycotoxins in fish, it is of extreme importance that the levels of mycotoxins in feed ingredients used are known. But to what extent can we find these dangerous metabolites in feed ingredients? Every year BIOMIN conducts a mycotoxin survey to answer this question regarding contamination of the agricultural commodities in different regions worldwide. Between the period of January and December 2012 a total of 4,023 samples were analysed and 14,468 analyses were carried out for the most important mycotoxins in terms of agriculture and animal production - aflatoxins (Afla), zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FUM) and ochratoxin A (OTA). The analyses were performed at different certified labs and all samples were analysed by HPLC. For the purpose of data analysis, nondetection levels were based on the quantification limits of the test method for each mycotoxin - Afla (4 ppb), ZEN (32 ppb), DON (50 ppb), FUM (100 ppb), OTA (2 ppb). Concerning commodities, soybean meal, corn, corn gluten, DDGS, rapeseed, wheat flower, rice bran are important ingredients of fish and shrimp diets in aquafeeds. Therefore, the following tables present an overview of the number of analysed samples, the percentage of positive samples, the average of positive results and the maximum contamination found of the above mentioned ingredients. An overview of the results of contamination by commodity is presented in tables 1 through 7. It is possible to verify that corn was one of the raw materials more contaminated with DON and FUM present in 64 percent and 86 percent of positive samples and 668 ppb and 1,666 ppb were the average levels, respectively. Corn gluten was highly contaminated with ZEN, DON and FUM (86 percent, 95 percent and 90 percent respectively). Levels were 1,096 ppb for ZEN, 3,049 ppb for DON and 2,559 for FUM. In regards to DDGS, the percentage of positive samples was also very high for ZEN (76 percent), DON (85 percent) and FUM (79 percent). Levels in DDGS were also high with 385, 4,241 and 1,426 ppb for ZEN, DON and FUM respectively. These levels table 4: DDGS DDGS afla Zen Don FUM ota number of tests 64 63 65 57 50 Percentage of positive (%) 31 76 85 79 Co-occurance 46 average (µg/kg) Maximum (µg/kg) 5 385 4,241 1,426 3 105 2,606 28,005 11,594 48.8 Zen Don FUM ota table 5: rapeseed rapeseed afla number of tests 10 15 15 10 10 Percentage of positive (%) 20 20 47 0 30 average (µg/kg) 0 2 121 0 0 Maximum (µg/kg) 0 13.5 685.2 0 3.1 16 | INterNatIoNal AquAFeed | November-December 2013 Co-occurance
  5. 5. FEATURE table 6: Wheat flour Wheat flour afla Zen Don FUM ota number of tests 172 341 434 189 186 5 31 70 10 13 Percentage of positive (%) average (µg/kg) 0 38 842 33 0 11.1 2,991 12,000 2,273 30 rice bran afla Zen Don FUM ota number of tests 22 22 22 21 22 Percentage of positive (%) 45 41 18 24 32 average (µg/kg) 1.5 56 128.2 181 1.3 Maximum (µg/kg) 61 165 648 220 Co-occurance 1.7 Maximum (µg/kg) table 7: rice bran indicated that processed products are increasing the risk of mycotoxin contamination in the feeds. Afla, ZEN and OTA presented higher contaminations (18 percent, 19 percent, and 26 percent, respectively) in soybean meal. In regards to wheat flour, ZEN and DON were the most prevalent mycotoxins with 31 percent and 70 percent of positive samples and average levels of 38 ppb and 842 ppb, respectively. Finally, rice bran was mostly contaminated with Afla, ZEN and OTA testing positive at 45 percent, 41 percent and 32 percent, respectively. Levels of 100 ppb of DON have been reported to cause harmful effects in Co-occurance trout and shrimp. Similar or even higher levels were found in several ingredients. 60 ppb of Afla in most fish species such as trout, pangasius, tilapia, shrimp, catfish, European seabass represents a risk of low to medium. Conclusion The available studies on the effects of mycotoxins in fish and shrimp show that performance and health status are negatively affected. The analysed concentrations of mycotoxins in feed ingredients used in aquafeeds, shows the importance of management strategies for the mycotoxins problem. The awareness of mycotoxin problems in aquaculture farms must be developed to minimize the negative impact of mycotoxins on the performance and health of exposed fish. Moreover, the risk for consumers needs to be addressed as mycotoxin residues were found in fish muscle beyond acceptable levels. For that, further research is needed in this topic and of course, an effective mycotoxins risk management must be taken into account. References available upon request More InforMatIon: Website: Die and roll re-working machines SPANISH LANGUAGE EDITION EDICION ESPANOLA Phone: +45 75 14 22 55 Fax: +45 82 28 91 41 mail: November-December 2013 | INterNatIoNal AquAFeed | 17 O&J Højtryk A/S Ørnevej 1, DK-6705 Esbjerg Ø CVR.: 73 66 86 11
  6. 6. LINKS This digital re-print is part of the November | December 2013 edition of International Aquafeed magazine. Content from the magazine is available to view free-of-charge, both as a full online magazine on our website, and as an archive of individual features on the docstoc website. Please click here to view our other publications on • See the full issue I N C O R P O R AT I N G f I s h fA R m I N G T e C h N O l O G y Animal co-product hydrolysates: • Visit the International Aquafeed website • Contact the International Aquafeed Team • Subscribe to International Aquafeed – a source of key molecules in aquaculture feeds Prevalence of mycotoxins in aquafeed ingredients: – an update Pellet distribution modelling: – a tool for improved feed delivery in sea cages New functional fish feeds to reduce cardiovascular disease Vo l u m e 1 6 I s s u e 6 2 0 1 3 - N oV e m B e R | D e C e m B e R To purchase a paper copy of the magazine, or to subscribe to the paper edition please contact our Circulation and Subscriptions Manager on the link above. INFORMATION FOR ADVERTISERS - CLICK HERE