NEWS
Biomin mycotoxin survey: Focus on the main risks in aquafeed
levels above 1000ppb. Deoxynivalenol, one of the most common mycotoxins, is highly toxic to rainbow trout: reduction of feed efficiency and growth occurs at levels of 1ppm. Salmon feed contaminated with 3.6 parts per million (ppm) caused a 20 percent reduction in feed intake and an 18 percent increase in FCR. Long-term exposure effects of fumonisin B1 (FB1) reported in carp showed that exposure to 0.5 and 5.0mg per kg body weight is not lethal to young carp, but can produce adverse physiological effects with kidney and liver being the key target organs for FB1 action.
found worldwide—aflatoxins (Afla), zearalenone (ZEN), deoxynivalenol (DON), T-2 toxin (T-2), fumonisins (FUM) and ochratoxin A (OTA)— species have not yet been fully eluwere analysed in all of the samples quaculture feeds have (see Table 1). moved away from their cidated. However, several studies have In addition, a specific survey which dependence on fishmeal included 41 aquafeed samples (fish/ as the main protein source and reported the detrimental effects of shrimp) from the Asian region was now rely mainly on plant protein mycotoxins at low levels. For example, Pangasius fed diets included. sources. How then will this affect More than three-quarters of the mycotoxin exposure in aquatic contaminated with 60 parts per billion (ppb) aflatoxin suffer affects aquafeed samples were co-conanimals? taminated with two mycotoxins or With fishmeal and fish oil on their growth and increased liver more and 93 percent of samples becoming increasingly expensive, damage. A different study, also with contained at least one mycothe inclusion of terrestrial plant- Pangasius, showed that at levels of toxin. The highest incidence was based proteins in commercial aqua- 50ppb the fishes' resistance to chalobserved for DON at 68 percent, culture feeds has gained widespread lenge by the bacterium Edwardsiela followed by ZEN and Afla at 59 acceptance. Even feeds for carnivo- ictaluri is reduced. Another study percent each.The average Afla conrous species are now formulated to on yellow catfish with AFB1 levels centration was 49ppb, a level that contain more than 50-70 percent above 250ppb showed increased feed conversion rate (FCR) and Aquafeed samples poses a health risk to aqua species. of plant-derived matter. One aquafeed sample contained A common problem that arises reduced weight gain. In shrimp, contaminated from the use of plant ingredients is levels as low as 20ppb have been In the Biomin Mycotoxin FUM at 7534ppb. Corn samples contained the the presence of mycotoxins - toxic found to reduce weight gain. Survey 2014, the main ingrediDiets contaminated with ents intended for the aquacul- highest average and maximum consecondary metabolites produced by filamentous fungi which fre- 100ppb Zearalenone (ZEN) ture industry including corn, corn centrations of Afla, ZEN, DON quently contaminate agricultural reduced weight and increased DDGS, soybean meal, wheat, wheat and FUM among all samples. As FCR in white shrimp, while bran and rice bran were evaluated. expected, DON and FUM were the commodities. Mycotoxins are mainly produced survival was affected with ZEN The five most common mycotoxins most frequently found mycotoxins in corn with a prevalence of under warm and moist con72 percent each, followed by ditions typical of the tropical Table 1: Detailed results of mycotoxin occurrence by commodity ZEN at 55 percent. and subtropical countries Afla ZEN DON T-2 FUM OTA The highest Afla, DON where most aquaculture Aqua Number of samples tested 37 37 37 41 37 and FUM prevalence was is practiced. Temperature Feed % of contaminated samples 59% 59% 68% 51% 57% observed in corn DDGS. resistant, mycotoxins are not Average of positives (ppb) 49 71 162 637 2 The highest average level destroyed by the heat and Maximum (ppb) 221 306 413 7,534 5 and maximum concentrapressure of pelleting and Corn Number of samples tested 1010 1557 1834 766 970 879 tion of OTA was determined extrusion. % of contaminated samples 22% 55% 72% 16% 72% 5% in soybean meal samples at 24ppb and 141ppb respecCrop contamination Average of positives (ppb) 49 443 2,651 74 2,974 3 tively. DON is the most over 25 percent Maximum (ppb) 1,352 16,495 29,600 852 154,000 41 common mycotoxin found The Council for Corn Number of samples tested 59 61 58 42 59 55 DDGS in wheat samples with an Agricultural Sciences and % of contaminated samples 41% 74% 83% 26% 78% 29% incidence of 56 percent. The Technology (CAST) in 2003 Average of positives (ppb) 13 250 834 28 1,808 4 highest average T-2 level was estimated that 25 percent Maximum (ppb) 196 3,600 5,941 80 27,665 22 detected in wheat samples of the world's crop producSoybean Number of samples tested 79 79 80 59 79 79 at 100ppb. The highest incition was contaminated with Meal % of contaminated samples 13% 24% 16% 3% 15% 20% dence of DON among all mycotoxins. Average of positives (ppb) 3 17 278 12 117 24 samples was determined Over the past 10 years in wheat bran samples. The of the Biomin Mycotoxin Maximum (ppb) 10 101 1,166 13 746 141 highest prevalence of Afla Survey, the evaluation of Wheat Number of samples tested 160 339 523 147 148 166 (40 percent) was deteralmost 33,000 samples from % of contaminated samples 8% 32% 56% 12% 14% 9% mined in rice bran. around the world revealed Average of positives (ppb) 11 75 882 100 350 3 Mycotoxin analyses in that more than three Maximum (ppb) 87 2,115 28,864 1,300 2,935 10 this survey clearly indicate quarters of these samples Wheat Number of samples tested 67 69 69 17 60 62 that constant monitoring were contaminated with at Bran % of contaminated samples 3% 28% 93% 18% 17% 26% of mycotoxins is important. least one mycotoxin and 43 Average of positives (ppb) 2 124 760 5 605 3 An effective mycotoxin risk percent of all samples were Maximum (ppb) 3 1,491 3,806 10 4,333 18 management program is co-contaminated with two Rice Number of samples tested 25 25 25 17 25 24 essential in order to protect or more toxins. Bran animals from the negative While in terrestrial animals % of contaminated samples 40% 56% 8% 0% 72% 21% impacts of mycotoxins on the toxic effects of mycoAverage of positives (ppb) 5 43 24 85 4 their health and perfortoxins have been widely Maximum (ppb) 11 200 25 282 18 mance. studied, the effects in aquatic
A
12 | INTERNATIONAL AQUAFEED | July-August 2015