01/11/2016: Mycotoxin levels put farmed species at risk

by Rui A. Gonçalves, Scientist at BIOMIN

The negative effect of mycotoxins in aquatic species has been highlighted in recent publications.

Mycotoxins can cause adverse effects in several aquatic species and these effects vary greatly depending on a variety of factors including nutritional and health status prior to exposure, dose and duration of exposure, age and species.

Nonetheless, the important question that remains to be answered: which species can the real-life mycotoxin levels in aquafeeds affect? Comparing results of the BIOMIN Mycotoxin Survey with known sensitivity levels of farmed fish and shrimp reveals that numerous species are at risk in terms of impaired health or lower performance—undermining the industry’s profitability.
  

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Mycotoxin occurrence
Over a period of one year, 41 samples of finish aquaculture feed, both shrimp and fish, were analysed within the scope of the annual BIOMIN Mycotoxin Survey program. The samples were sourced in Asia (31 samples) and Europe (10 samples). In all, 154 individual analyses have been conducted. The samples were tested for aflatoxins, zearalenone, deoxynivalenol, fumonisins and ochratoxin A.

Deoxynivalenol
Directly comparing literature values with contamination levels found in the survey (Figure 1), we can observe that several species can be affected by DON in real aquaculture production scenarios.

In European samples, an average value of 165 ppb (parts per billion) and maximum of 282 ppb of DON was detected and in Asian samples an average value of 161 ppb and maximum of 431 ppb of DON was found. These values are within the sensitivity level of rainbow trout, pacific white shrimp, carp and red tilapia production.

Aflatoxins
Aflatoxins were the most common mycotoxin found in the survey for Asia. Aflatoxins have been considerably investigated in farmed fish and crustaceans’ species due to the toxicity of AFB1. The contamination values of aflatoxins found for Europe were negligible (0.43 ppb); however, the values found for Asia (average = 52 ppb and maximum of 221 ppb) can impact several rearing species (Figure 2).

These aflatoxin levels could spell trouble for rainbow trout, European seabass, Nile tilapia, rohu, yellow catfish and white leg and black tiger shrimps, amongst many others. While the aflatoxin contamination appears restricted to Asian samples, the global trade in raw materials and aquaculture feeds could potentially export the occurrence of mycotoxins to other regions.

Read the full article HERE.

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