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GUTINTEGRITY
Gastrointestinal functions and food intake regulation in salmonids: Impact of dietary vegetable lipids

Sustainable and ethical aquaculture is of future economic importance for the many rural areas of the European Union. To achieve this, the industry needs to lessen its dependence on fish meal and oil as a basis for fish feed. Vegetable lipids may be a major source of alternative energy for cultured fish, but current knowledge of their effects on the gastrointestinal tract of fish is insufficient to give recommendations on the content and composition of fish feed. The objective of the project is, through a multidisciplinary approach applying a series of innovative techniques, to elucidate how feed lipid content and composition affects the integrity and function of the gastrointestinal tract. This will establish a basis for how vegetable lipids could be incorporated into the feed of salmonids in European aquaculture.

Objectives
The overall goal of the project is to provide a strong factual basis for the quantitative and qualitative incorporation of vegetable lipids into feed for salmonids, a group of a commercially important European aquaculture species, without compromising the growth, health and welfare of the fish.
In order to reach the overall goal, three major project objectives will be achieved:
1) a comprehensive understanding about how vegetable lipids affect the vital physiological functions of the gastrointestinal tract, including the absorption processes, active nutrient uptake mechanisms, intestinal barrier function, indigenous intestinal microbiota and disease resistance
2) a broad knowledge about how lipids (especially vegetable lipids) affect the voluntary food intake, how this is mediated through postprandial signals by regulatory gut peptides and hormones, and how fish are able to discern between lipid sources
3) an integrated clarification of how the overall health of the fish (performance during development, growth, welfare and ability to recover) is affected by the disturbance of the intestinal integrity by dietary vegetable lipids.

Progress to Date
The project is progressing well within the work plan.

Results
The completion of the extreme diet feeding trials clearly demonstrated that the fish both fed and grew well, and even exceeded expected growth rates. On the other hand, it was also clear that all groups fed vegetable diets seemed to have had a disturbed intestinal barrier function compared with the reference group that were fed a commercial diet throughout the experiment. The effect was more pronounced for diets that contained rapeseed oil and sunflower oil. However, it also demonstrated that the fish both fed and grew very well, even exceeding expected growth rates, when fed the different vegetable diets.
The food preference study demonstrated that fish were capable of discriminating between different food sources, and that they exhibited a dietary preference. Despite important changes in relative food preference, no differences were observed in the total food intake expressed in absolute amounts (g per individual per day), nor in final body weight between fish under the different dietary treatment combinations.

Classified in HORTICULTURE, NON-FOOD PRODUCTS, CAP AND RURAL DEVELOPMENT, FISHERIES AND AQUACULTURE

Scientist responsible for the project

Prof BJÖRN THRANDUR BJÖRNSSON
Medicinaregaten 18
41390 Göteborg
Sweden - SE

Phone: +46 317733691
Fax: +46 317733807
E-mail: thrandur.bjornsson@zool.gu.se

References

Project ID QLRT-1999-31656
Organisation Göteborg University - Department of Zoology/Zoophysiology
Area 5.1.2
Start date 01 October 2000
Duration (months) 36
Total cost 2 048 158 €
Total EC contribution   1 230 000 €
Status Completed

The partners

  • Finnish Game and Fisheries Research Institute - Evo Fisheries Research Station, Finland - FI
    kari.ruohonen@rktl.fi
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