R&D applications for aquafeed extrudates: Laboratory scale testing to determine appropriateness for species and sustainability

by Brabender, Germany

Providing a proper supply of protein for the world's continuously increasing population is a tremendous global challenge. Consumption of fish and seafood is traditionally anchored in many dietary cultures and recommended as a significant source of protein for nutritional enhancement.

However, in view of the present situation with overfished oceans around the globe, it is necessary to find alternatives: Here aquaculture provides a solution. Consequentially the global annual yield from aquaculture, amounting to approximately 100 million tonnes since 2015, has outstripped the "wild catch" quantity for human consumption.
 

Further growth is a foregone conclusion: A 50 percent increase in production is predicted for the next two decades.

Booming aquacultures: Which feed for which species?

We spoke with Julian Foerster (JF) and Michael Landers (ML), the application technicians at Brabender's extrusion laboratory, about using custom tailored extruded products to solve the problems presently faced by the aquafeed industry.

Extruded aquafeed – Where does demand exist?
JF: Whether fish farming with flow-through systems, netcages, or resource-preserving recirculating systems such as aquaponic or offshore farms – all these fish and crustaceans need feed; nearly 40 million tonnes per year worldwide.

70 percent is produced by the leading aquafeed producers in the Asian-Pacific region, particularly in China, 10 percent comes from Latin America, and another 10 percent from Europe. Of course, one has to differentiate among which species should be fed.

Presently 30 percent of production is used for carp breeding, 15 percent is required for crustaceans, followed by tilapia, catfish, salmon, and trout farms.

ML: Extruded products offer trend-setting possibilities promising market success and product innovation in developing the proper feed for each species on a practical basis. There is practically no other process that offers so much potential for entirely reshaping an aquafeed matrix.

For this reason purely mechanical pelleting presses have been increasingly replaced by state-of-the-art extrusion technology for production. Today, laboratory extruders are therefore necessary "tools" for product developers in companies as well as at universities and research institutes. With the TwinLab-F 20/40, Brabender has now introduced its current top model for the R&D laboratory world.

What is the "proper" feed for a species?
JF: First, we need to determine the raw materials and their percentage of protein and carbohydrate that are practical for various product applications. It is first necessary to determine the tendency of the feed to float or sink, depending on the feeding habits of the specific type of fish.

In principle, floating feed tends to be eaten by bottom fish such as carp and catfish, which can also be a matter of training. Salmon and trout prefer feed that sinks slowly, shrimp, by contrast, like food that sinks quickly.

ML: Correspondingly, it is necessary to select different process settings for production. For floating feed, including suspended or slowly sinking feed, we operate with hot extru-sion at temperatures over 100°C. This results in good pellet expansion. For sinking feed, i.e. production of quickly sinking pellets with minimum expansion, cold extrusion is the preferable method.

Read more, HERE.

The Aquaculturists

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