Aqua Feed

The FAO (Food & Agriculture Organisation of the United Nations) reports that global aquaculture continues to grow. Aquaculture today supplies more than half of all fish for human consumption, and global fish consumption per capita more than doubled over the last 50 years.

It, therefore, comes as no surprise that aquatic feeds became the fastest growing feed sector when compared to other animal feeds and pet food, and is currently growing at approximately 7% per year.

The ultimate goal of aquaculture is:
• to produce healthy edible protein
• to produce edible protein at the lowest possible cost per kilogram.  FCR (Feed Conversion Ratio) and SGR (Specific Growth Rates) are therefore key performance indicators of manufactured aquatic feed and indirectly the technology used to produce them
• to do the above with negligible effect on the environment

Ottevanger Milling Engineers & Aquatic Feed Manufacturing

Aquatic feeds have very high requirements in terms of both nutritional and physical characteristics of feed. These nutritional and physical feed requirements are driven by the life stage of a specific species under consideration. Physical characteristics include issues such as pellet size and shape; pellet density allowing us to produce floating, slow sinking and sinking feeds; water stability and pellet durability. The challenge is to achieve all of these while having a negligible effect on the environment.

Ottevanger Milling Engineers keep these and other project specific issues in mind when designing an aquatic feed processing plant.  The choice of equipment, technologies, processes, and equipment is, therefore, the key to success.  We take time consulting with customers to ensure we fully understand customer requirements and more specifically requirements of the specific market the customer is serving.  We do not promote or apply a “standard” Aquatic Feed Plant design and each project is assessed on its own merits.

The following schematic presents the basics of the Aquatic Feed manufacturing process:

Careful consideration of intake, cleaning and storage of both dry and wet raw ingredients.Dust control, odour control and potential cross-contamination enjoys special attention during design.

The nature and type of wet ingredients to be used in formulations determines the processing technology we apply and the subsequent infrastructure required. Introduction of wet ingredient is introduced into the process at a point where the risk of cross-contamination is minimised

Aquatic feeds require fine grinding in order to optimise the thermal and shaping processes (extrusion or pellet pressing). In addition, small diameter hatchery feeds require superior grinding to average grist size as fine as 200 micron. Ottevanger supplies size reduction solutions meeting these requirements while avoiding heat damage of costly ingredients.

Conditioning - extrusion - pelleting

The choice of extrusion technology is determined by raw ingredient, formulation and final product requirements in terms of size, shape and density (buoyancy). (The right type of) Extrusion technology is the only solution producing floating, slow sinking and most sinking Aquatic Feeds. Shrimp feeds are traditionally manufactured through Pellet Pressing. However, extrusion solutions are available for producing extruded shrimp feeds as well.


Different approaches are followed for drying and cooling of semi-moist aquatic feeds compared to conventional aquatic feeds. The same applies for application of liquids. Ottevanger have several options for coating – vacuum coating included. The Ottevanger vacuum coating process allows for layering liquids and attractants.


Semi moist aquatic feed requires a different approach to intermediate storage of final product to minimise the potential of product damage. Final product storage and bagging design includes a bulk load-out system; a bulk bag loadout system; a bagging plant for small bags or any combination thereof. Project requirements are carefully considered with the customer’s specific requirements in mind.

Process control

One of the key issues to successful aquatic feed manufacturing is a process control system designed to meet functional, operational and quality requirements. This includes careful consideration of process Critical Control Points and online control of processing parameters, such as moisture content and the amount of SME (Specific Mechanical Energy) required to produce final product of specific density.

Environmental control

At Ottevanger Milling Engineers we take great care of the environmental impact of our plant design.  The potential impact of aquatic feeds on the environment and how this is affected by processing technology, is seriously considered during design and establishment of such plants.   The control of Dust, Odour , Noise and the Visual Impact of our processing solutions also enjoy detailed attention.