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ANDRITZ extrusion technology for shrimp feed production

A variety of factors influence the formulation of a quality shrimp feed recipe; factors such as the environment in which shrimp are raised, their nutritional needs at different stages of development, their feeding behaviours, and of course, raw ingredients utilised all play a part in crafting a feed that will result in maximum growth

Ultimately, however, equipment designed with the flexibility to produce a pellet with all the right attributes – at every stage, is the key to successful aquafeed production. ANDRITZ has the knowledge and the tools that provide feed producers with the advantages they need in a competitive marketplace.

Extrusion Technology

Extrusion technology is used to compress, mix, and heat raw materials, applying pressure and temperature to destroy bacteria and other microorganisms while maintaining the integrity of the fats and proteins that are essential for growth. This process adds to the overall energy value of the feed by opening up fat cells, releasing their contents, and increasing energy concentration.

Additionally, starch, gluten, and other synthetic binders are used to hold pellets together but have no real nutritional value for the shrimp. When extruding pellets, the starch content can be to as low as 10 per cent. This reduction in binders also means producers have more flexibility when it comes to choosing ingredients for their feed recipe, ultimately allowing for more nutritious choices. This process results in improved feed conversion and a higher quality product at reduced production costs.

ANDRITZ Extrusion Technology

With most extruders, screw configuration can be optimised with the specific mechanical energy (SME) necessary to achieve the product requirement through screw design and geometry, adjustments to the shear locks and kneading elements. Sometimes, however, these adjustments alone may not be capable of creating sufficient SME, and it becomes necessary to make changes to other parameters. If modifications to the screw speed, the open area of the venture die, the die plate or the extruder’s capacity are necessary, these changes can take hours to complete and result in downtime and increased production costs.

The ANDRITZ FLEXTEX™ system allows for continuous control of SME - during operation, without changing the extruder configuration or any of the parameters mentioned above and the system, located between the screw and the die plate, provides precise control over the pressure in the kneading zone as well as the SME, cutting down on the amount of energy consumed.

The FLEXTEX technology cooks the binders 100 per cent, resulting in a feed with a higher oil/fat content and less starch, while also controlling the bulk density, which can be reduced by up to 30 per cent. Additionally, the pistons in the FLEXTEX system move axially and, at the same time, conically so that meal flow always remains even as it comes into contact with the die plate. This means there are fewer parts to maintain and fewer fines, greater utilisation of raw ingredients, less risk of contamination, increased water stability, and superior visual quality.

The Andritz Expansion Control System (ECS™) is unique in its ability to control the bulk density of a wide range of feed formulations while optimising product quality. Expansion of extruded feed is controlled by adding the patented ECS under the knife house and compressed air inside the knife house. This combination makes it possible to govern and adjust the pressure, reduce flash-off, and ultimately, increase the bulk density, while simultaneously maintaining the essential amino acids.

So, whether it’s sink or swim, ANDRITZ extruders will keep your aqua feed production afloat. By combining the patented ANDRITZ Expansion Control and Flextex Systems, shrimp feed producers can achieve perfect product density and sinking speed, so your feed is always a big splash.

Click here to know more! or contact ANDRITZ sales manager, Dieter Rohlf ( for more information.