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Mycotoxins and farm fish: an underestimated risk Logo Feedia

Mycotoxins are toxins produced by fungal moulds. They usually develop on grains during harvest and storage. High concentrations of these metabolites can turn out to be toxic, especially if they are ingested by certain species of farm fish. Whether you are a farm fish breeder or a feed manufacturer, you may wonder how the mycotoxin threat can be contained. How can their impact on farm fish be reduced?

There are several types of mycotoxins:

  • those that develop before harvesting period

  • those that develop during the storage period

  • those that occur during harvest and storage.

Classification of mycotoxins according to their origin

Why mycotoxins may pose a risk to farm fish?

The threat posed by mycotoxins is complex as their presence is difficult to detect. The reactions they provoke vary depending on the species of fish that ingests them and the level of the toxin in the food. As a result, their effects are difficult to predict and categorise.
The mere presence of moulds on grain is not necessarily a sign of their presence. Yet the absence of fungus doesn’t mean that the grain is devoid of them either. Their specificity – and the danger that stems from them – also comes from their ability to resist heat and pressure even after feed is extruded.
In addition, the impact of mycotoxins changes depending on the kind of fish that consumes them. Let’s take the example of Aflatoxin B1, one of the most common mycotoxins: rainbow trout may be very sensitive to it, yet catfish are not. When rainbow trout ingest Aflatoxins  B1, they transform them through the digestion process and metabolize them in the form of much more harmful substances.

Why is the danger of mycotoxins currently worsening with regards to farm fish?

Because the proportion of plant-based ingredients in fish feed formulation has significantly increased over the past few years. Fish have a high need for protein. Fish meal is the source of food that best suits their metabolism. Indeed that kind of meal contains a high concentration of protein as well as plenty of indispensable amino acids. However, the rising costs of fish mealand its lack of availability on the market have drawn nutritionists to resort to ingredients derived from plant matter in order to replace fish meals. Here lies the risk of mycotoxins, as plants are likely to contain them. Hence the presence of mycotoxins in ingredients derived from plant matter needs to be monitored closely.

How to reduce mycotoxin danger?

The danger stemming from the presence of mycotoxins in fish feed is serious as these metabolites are likely to have severe impacts on fish development and productivity. Below is a list of various actions Techna recommends that you undertake in order to control the evolution of mycotoxins:

  • Introduction of multi-detection procedures in the quality control plan of agricultural raw materials and finished products. These procedures will vary according to the nature and origins of the raw materials contained in the manufactured feed.
  • Increasing the frequency of analysis at the beginning of the harvest so as to assess promptly the quality of the new grain.
  • Should the risk be validated (established presence of mycotoxins, low-quality crops, substantial amount of cereal by-products), Aquatechna advises you to incorporate toxin binders directly within the feed.

Other alternatives exist depending on the species of fish, the “nature” of contamination, and the type of fish culture. To learn more, please contact our Techna experts!

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