SalmoPUFA

You are what you eat is a long-standing assumption in ecology that has been validated across diverse ecosystems, ranging from terrestrial to aquatic food webs. Nutritious quality of diet is indeed a key factor that affects characteristics of individuals, but its effects in interaction with other stressors like water temperature are not well understood. Climate change is predicted to cause an increase of water temperatures and decrease the amount of available essential nutrients in aquatic ecosystems during the next century. Therefore, there is an important knowledge gap that needs to be addressed: How do wild fish cope with changes in diet quality under conditions of rising water temperatures? Vertebrates including fishes and humans cannot synthetize long-chain polyunsaturated fatty acids LC-PUFA and thus they need to be supplied by diet, which makes LC-PUFA essential dietary nutrients of high ecological importance. The aim of SalmoPUFA project is to explore how diet quality and water temperature affect brain and eye tissue development, whole-animal metabolism, learning capacity, and behavioural traits in salmonid fishes. We use brown trout Salmo trutta as a model species because it is a typical species living in small streams and its individuals expresses permanent differences life history and feeding strategies. We will combine feeding and water temperature treatments in a long-term laboratory experiment, which will consist of two parts: first, individuals exposed to the abovementioned treatment will be challenged by a set of standardized behavioural trials to evaluate their behaviour and capacity to learn new tasks. Second, we will measure how much oxygen individuals consume to sustain their minimal resting metabolism and how much they consume immediately after exhaustive exercise. This information will help us understand the energy budget of their metabolism. In addition, in both part of the project we will evaluate differences among treatments in somatic growth, size, and condition factor, in lipid composition of liver, muscle, and neural tissue using spectrometry, and differences in brain morphology using a picture analysis. Results from this project will provide fundamental knowledge about how diet and temperature changes fish behaviour and physiology. This new knowledge will be helpful for the management of salmonid fishes, which are used as an important human food source (e.g. industrial fisheries and aquaculture) and for recreational fishing. Developing our understanding about the role of dietary LC-PUFA and temperature on performance of salmonids can help us improve welfare of salmonid fishes kept in hatcheries and fish farms and increase fish survival to individuals stocked to our lakes and rivers. Project results can also help find a better balance between ecological costs of fish meat production and high quality food for human consumers.

No additional funding sources recorded.