KreAktiv – Fish Feed for Performance, Sustainability, and Animal Welfare

Background and Objective

Fish feeds for the rearing of salmonid fish have undergone significant development over the past decades. These advances primarily aimed to replace animal fats and protein sources with plant-based alternatives and to remove antinutritional substances present in plant ingredients. However, the availability of plant protein sources is also limited and increasingly needed for the direct nutrition of a growing global population. Therefore, for fish production in aquaculture, it is necessary to reduce the amounts of fats and proteins as energy sources and to replace them with carbohydrates. The cultivation and production of carbohydrates require fewer resources than those of protein and oil sources.

Trout are carnivorous predatory fish that can utilize carbohydrates in feed only to a limited extent. The use of carbohydrates in the diet of carnivorous fish is therefore restricted. However, studies have shown that the stimulation of swimming activity can improve carbohydrate utilization. In addition, the digestibility and usability of carbohydrates can be further enhanced through functional supplements. The combined application of such supplements with targeted stimulation of swimming activity has not yet been investigated, and it remains unclear which combination of these parameters is most effective.

The aim of the KreAktiv project is therefore to investigate whether the utilization of carbohydrates can be improved by specifically stimulating swimming activity at defined flow velocities while simultaneously administering dietary supplements through the feed.

Approach

We conduct feeding trials in aquaria to determine the optimal feed composition and the most effective levels of supplementation, followed by laboratory analyses. Subsequently, we carry out feeding trials in circular flow tanks, where we specifically stimulate swimming activity at defined relative swimming speeds and provide the feed that yielded the best results in the first experiment. After these trials, we again perform detailed laboratory analyses.