Reports

Moist diet for farmed fish

Published:

01/02/2009

Authors:

Jón Örn Pálsson

Supported by:

AVS Fisheries Research Fund. Preliminary project (S 034‐05)

Moist diet for farmed fish

Gellyfeed is a synonym for a two-stage production process of aquaculture feed. The method was developed with the aim of reducing storage costs and producing strong feed pellets. Studies confirm that long-term leaching of raw materials and storage impairs the quality of proteins and renders the raw material unsuitable for wet feed production. The maximum shelf life of fish raw material in a strong alkaline state is 14 days. The method can be useful for killing bacteria, viruses and parasites. Options for storage of raw materials for wet feed production are freezing and digestion processing. The production of wet feed from by-products that occur in the northern Westfjords can be a promising option. The legislation of the European Economic Area does not prohibit the use of by-products from wild cod in feed for farmed cod.

Gellyfeed is a name of a two-step production process of moist diet for farmed fish. The process is developed to reduce the cost of preserving by-products and to make a physical strong pellet. Research confirms that alkaline preserved raw material and longtime storing damage the protein quality and make the raw material not suitable for use in moist diet. Maximum storing time of alkaline preserved by ‐ products is 14 days. The process can be practical for eliminating harm from bacteria, viruses or parasites. The alternative methods for storing by ‐ products are freezing or silage production. Moist diet produced from by ‐ products from the northern region of the Westfjords in Iceland seems to be economically promising option. The legislation from the European Union does not forbid using by-products from wild cod as a raw material in production of moist diet.

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Reports

Solutions due to environmental impact during stroke release

Published:

01/09/2007

Authors:

Heimir Tryggvason, Guðrún Anna Finnbogadóttir

Supported by:

AVS Fisheries Research Fund

Solutions due to environmental impact during stroke release

In recent years and decades, satisfactory solutions to sludge discharge have been sought. Considerable emphasis has been placed on finding ways to process the slug into usable products that could be sold. This work has mainly been done by individuals, organizations and institutions. In this connection, one can mention plans for digestion from slag to feed production, but these experiments were well under way in the mid-1980s. It can be said that the problem with slag processing is twofold. The slag is damaged very quickly, which makes it difficult to use it in certain products. Secondly, the transport cost is high compared to the value of the product made from slag. The way in which slag is discharged varies greatly from one situation to another, but the growing emphasis on environmental issues in recent years has fueled old ideas about the utilization of slag.

In recent years, a considerable effort has been made to ensure a proper disposal of viscera from fish processing. The emphasis has been on processes that could return a marketable product. In the late 20th Century a lot of this work was focused on silage production. There are mainly two major problems with regard to the processing of viscera: Firstly, viscera spoils very rapidly, which makes it difficult to use in many products. Secondly, the cost of transportation is very high compared to the value of the products processed from viscera. Handling of viscera is very diverse in different places but increased emphasis on environmental issues has raised the issue of utilization again.

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