Towards a better understanding and control of factors impacting the physical quality of fish feed.

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In the initial phase of the project, focus will be on finding crucial factors influencing the quality of the fish feed. Factors like processing parameters, raw materials used in production, formulation and the final product shape, texture and porosity wil l be studied in detail. Moreover, changes in the quality over time will be investigated. Next stage of the project will involve modifications of proteinaceous raw materials. One type of modification could be crosslinking of the product matrix. Results s hould be followed by extrusion trials. Development of novel production technologies could be another part of this work. The second type of modifications could be the enzymatic hydrolysis of proteins. Atfer some preliminary studies on optimization of the conditions, further trials should involve extrusion and modifying materials directly during the production process. The third part of the project will include studying novel materials, which even on small inclusion levels could improve feed quality signi ficantly. This could for example be hydrocolloids, like carrageenan, agar, guar gum or pectin. Also chitosan, the derivative of chitin, should be taken into consideration. Screening should start by searching substances that actively interact with other fe ed components. Promising materials should be evaluated further by extrusion trials. All novel products developed during this project need to be tested in fish trails to investigate their palatability, the resulting feed intake and feed conversion ratio. The majority of experiments will be carried out at in the facilities of Skretting ARC and, if necessary, at external laboratories.