The expectations from a modern fish feed are many. The feed should have the required nutritional profile, good digestibility and be attractive to the fish. In addition, the physical quality of the pellets is of vital importance to the farmers. The pellet should not crumble or release fat and must withstand storage and have the proper sinking rate. The growing use of vegetable raw materials makes it increasingly challenging to meet all these requirements at once and there is a need for new research in this area. Another reason for this work is that demands for physical quality are changing, due to factors including changing logistics, longer feeding tubes at the customer and new markets.
This is part of the background for the PhD project of Julia Wolska, 26 years of age and originally from Poland. Wolska has a master's degree in biotechnology and food analysis from the University of Gdansk. She moved to Norway a few years ago and began work for Skretting ARC in a temporary position in 2010. She was immediately attracted to the idea of doing a PhD project together with Skretting ARC.
“I have always wanted to do a PhD project but the idea of doing a strictly academic thesis didn’t appeal to me. I wanted to be certain that my project would be useful in real life. With this thesis it’s a win-win situation. I gain new knowledge and Skretting gains research results that hopefully can be used to develop better feeds in the future.”
The project is conducted together with Lund University in Sweden where Professors Olle Holst and Patrick Adlecreutz from the Department of Biotechnology will provide guidance.
Wolska’s PhD thesis is divided into five parts. In the first part of the project she will look at the factors that affect the physical quality of the feed, such as process parameters, raw materials used in the production and formulation. The shape, texture and porosity of the pellets will also be studied down to the smallest detail.
Using raw materials
The next two steps in the project will deal with raw materials.
“I will look into the possibility of using the raw materials to change the physical quality of the pellets. Here we can probably use some concepts that are common in other types of food production,” Wolska says.
The fourth step is the development of new manufacturing processes and production technologies to be able to produce feeds that combine the findings from the previous parts of the project.
The last step before any discoveries and innovations are implemented in the commercial feeds is to perform fish trials to ensure that potential new products live up to expectations when it comes to digestibility, growth, fish health & welfare and the quality of the end product.
“It is of course essential that the changes we make with regard to raw materials do not have any kind of negative impact on fish health, welfare or quality of the end product," says Wolska.