Aquaculture is the fastest-growing food production industry in the world. Due to concerns about sustainability, the need to replace fish meal with plant-based protein alternatives becomes more urgent. However, plant-based ingredients are often contaminated with mycotoxins, increasing the health risks to fish.
Plant-based ingredients in commercial fish diets include maize, soybean meal and various cereal grains, each representing a potential source of mycotoxins.
Mycotoxins in fish feed a widespread problem
Mycotoxin-contaminated fish feed is a widespread problem, especially in tropical regions and developing countries where the farmers themselves often make fish feeds under inappropriate conditions with improper milling and/or storage. In addition to their impact on fish health, some mycotoxins can also accumulate in fish tissue, thereby posing a possible food safety risk.
About mycotoxins in aquaculture
According to a recent risk assessment study on mycotoxin contamination in fish feeds in Europe, deoxynivalenol (DON) is one of the primary mycotoxins present. DON is produced by over 50 species of Fusarium fungi, which mainly infect crops such as wheat and maize before harvest. Fusarium fungi produce a range of mycotoxins, such as fumonisins, the trichothecenes — most strongly associated with chronic and fatal toxic effects in animals and humans — and zearalenone, which is known to affect the fertility of many animal species, including aquatic species such as fish and shrimp.
The impact of mycotoxins depends on several factors including:
- The type and quantity of mycotoxins in the feed,
- Feeding level,
- Duration of exposure
- The species of fish
Most common issues include:
- Reduced growth performance,
- Immune suppression
- Increased mortality
These are often associated with other on-farm concerns, so the mycotoxin risk is currently underestimated.