Aquafeed sourcing, key to successful aquaculture sector

Mrs. Valeska Weymann, GLOBALG.A.P c/o FoodPLUS GmbH/Standard Management Aquaculture, Cologne, Germany

The aquaculture sector requires in most cases the need to supply  compound feed to the farmed organisms for proper growth and health;

 - Aquafeed appropriate sourcing plays a key role in the operational costs;

 - Feed coming from appropriate sourcing refers to: all raw materials used are subject of a risk assessment, including economical, supply chain, safety and ecological assessments;

- In the case that compound feed may contain fishmeal and/or fish oil, the species of fish used and its respective country of origin are desirable to be identified, together with a proof that it does not contain species classified as critically endangered or endangered on the IUCN Red List;

- At processing level: HACCP system shall be in place as well as consideration to workers health and safety;

- Animal protein shall follow legislation of country of production and purchase requirements of country of destination;

- Certification is a tool that compound feed manufacturers can adapt to support the need to demonstrate  responsible sourcing.

Trends in aquafeed: Relevence and technical solutions

Urs Wuest, Head Engineering & Fulfillment, Buhler, Switzerland

Changes throughout the entire aquafeed value chain will impact feed millers in the near future and beyond. Buhler will present the current trends in the Aquafeed industry to ensure feed and food safety and hygiene. This will include the changes in raw materials, feed manufacturing, aquaculture, processing of the fish and crustaceans and the demand from customers in total and by fish species. Further will be explained how changing requirements in the aquafeed industry translate into a demand for specific technical requirements, such as extrusion technology.

Planning a Strategic Path for Feed Safety in Aquafeed Plants

Joseph P Kearns, Aquaculture Process Engineering Manager, Wenger Mfg., Inc., USA

The developing trend in aquafeed plants is to insure feed safety throughout the production process.  A strategic path to accomplish this would be to assess and design the facility with attention to the following areas:  raw materials and their storage, plant equipment design, processing or operating procedures, final product efficacy and the overall culture or day to day operation of the plant.

Hygienic design principles for aquafeed plants and the equipment should be designed to achieve a cleanable HACCP level.  The equipment should be constructed of compatible materials with accessibility for cleaning and inspections with no material collection points or niches.

The way forward in aquafeed production safety is to strive to identify and validate critical control points in the process and operate on that basis.  Avoid recontamination in downstream areas after the critical points and install a finished product testing procedure for validation.

Multivariate modelling of extruded fish feed pellet quality

Tor Andreas Samuelsen ^1*, Svein Mjøs^1,2, Åge Oterhals¹

¹Nofima Ingrediens, Bergen, Norway

² Department of Chemistry, University of Bergen, Norway

Physical quality of extruded fish feed have become more important due to the use of bulk transport and pneumatic feed delivery systems. The complexity of the extrusion process, and limitations in basic knowledge on protein properties and protein/starch-interaction, make it a demanding task to obtain consistent product quality based on different types of raw materials. Changes in feed mash properties might lead to large quantities of feed pellets that are not consistent with product specifications and give increased production costs due to reprocessing needs or customer complaints.

Fishmeal at high inclusion level is a critical protein ingredient with respect to aqua feed processing and has a significant impact on pellet physical quality. Fishmeal is produced by use of heat coagulation combined with a mechanical and thermal dewatering process. 

We have studied the impact on pellet hardness and durability of commercial fishmeal parcels combined with low, medium and high water and steam input levels in the extrusion process.  Commercial fish meal parcels with a large variation in chemical composition and physical properties were produced from high quality herring at three different fishmeal factories in Norway. The experimental feed mixtures were processed on a Wenger TX-52 extruder at three moisture levels. The fishmeal quality was assessed based on 18 quality parameters and prediction models for pellet hardness, specific mechanical energy (SME) and starch gelatinization established based on partial least squares regression (PLSR) modeling. The study documented the possibility to develop a model explaining pellet hardness based on chemical and physical properties of fish meal and steam/water level in the process. The work also demonstrated that fishmeal physicochemical properties and added moisture had a significant effect on the melt viscosity and thereby dissipation of mechanical energy in the extruder barrel.

The information can be used by the aquatic feed industry to better understand and correct the observed variance in extrusion properties and pellet quality and to improve the product specifications used by fish meal producers and purchasers. Examples on how the knowledge can be used to solve problems in the extrusion process will be discussed.

Optimal pellet quality is a trade-off between durability and responses in the fish

T. Synnøve Aas^1,5*, Bendik F. Terjesen¹, Trygve Sigholt³, Marie Hillestad³, Jørgen Holm⁴, Ståle Refstie^1,6, Grete Baeverfjord¹, Kjell-Arne Rørvik², Mette Sørensen^2,6,7, Maike Oehme^1,5, Gaojie He^5,7, Torbjørn Åsgård^1,5

¹ Nofima, NO-6600 Sunndalsøra, Norway

² Nofima, Postboks 5010, NO-1432 Ås, Norway

³ BioMar, AS, NO-7484 Trondheim, Norway

⁴ BioMar A/S, Mylius Erichsensvej 35, DK-7330 Brande, Denmark

⁵ Centre for research based innovation in aquaculture technology (CREATE), SFI, SINTEF Sealab, NO-7645 Trondheim, Norway

⁶ Aquaculture Protein Centre (APC), CoE, P.O.Box 5003, NO-1430 Ås, Norway

⁷ Norwegian University of Life Sciences (UMB), Department of Animal and Aquacultural Sciences, P.O. Box 5003, NO-1432 Ås, Norway

Handling, storing and transport of feeds lead to attrition of the pellets. Undersized particles represent loss and poor utilisation of feed resources. Thus, feeds with high physical pellet quality are demanded. However, the physical properties affect the nutritional value of feeds. In a 48 days trial, two feeds, with high (feed A) or low (feed B) water stability, were fed to rainbow trout (Oncorhynchus mykiss) kept in sea water (salinity 32-34 ppm, temperature 12 °C, O2-saturation >80%). The feed intake was 23% higher in trout fed feed B than in those fed feed A. Introducing a daily period of lowered salinity (< 10 ppm), temperature (6 °C) and oxygen saturation (50-60%) resulted in a severe drop in feed intake in both dietary groups. However, the apparent digestibility of macronutrients was highest in feed A, but at fluctuating environment the difference between the dietary treatments was small. Furthermore, the stomachs of trout fed feed B, particularly of those kept at stable environment, contained large amounts of free water and oil, which could potentially lead to fat belching. Both apparent digestibility and free water and oil in the stomach seemed to be related to feed intake, and were thus indirectly caused by feed and environmental conditions. In another trial, pellet degradation of three commercial feeds (12 mm pellet size) during pneumatic conveying, which is commonly used in cage culture to transport the feed from the storage silo to the sea pens, was measured. The three feeds, chosen especially for having different physical properties, showed different degradation patterns during conveying. Furthermore, high air speed (m/s) in the conveying system, which is used to spread the feed pellets well in the cage, increased pellet degradation, whereas high feeding rate (kg/min) protected the pellets from breakage. In all runs, less than 1% of the sample ended up as small particles. In conclusion, feed intake appears to be a main factor when evaluating pellet quality, but several other factors, such as pellet durability, nutrient digestibility and fat belching must be taken into consideration when searching for the most economical and sustainable pellet quality.