Project

Fishing for Functional Feed

Farmed fish production had risen to meet-up with fish protein demand. Aquaculture diets consist of fish meal. However, due to its demand fisheries incorporated plant-based protein meals. Such replacement lead to intestinal inflammation and poorer nutritional intake. To date, a reliable, in vivo animal model for testing novel feed components for farmed fish is missing. This project aims to set up a pre-screening zebrafish model in order to disclose unique health-promoting feed ingredients such as anti-inflammatory properties for aquaculture diets.

Background

The demand of fish protein in diets is increasing worldwide. Since captured fish are not enough to fulfil that need, farmed fish production had risen accordingly. Aquaculture diets mainly consist of fish meal: a dried powder made out of unsold whole fish, fish bones and offal. The fish meal price increased due to its demand and fisheries tried to substitute it for plant based protein meals.

Project description

Plant based proteins meals lead to intestinal inflammation and poorer nutritional intake in the fish host. To date, a reliable, in vivo animal model for testing novel, healthy and sustainable food components for farmed fish is missing. The main aim of the project is to set up a pre-screening zebrafish model in order to disclose unique health-promoting feed ingredients such as anti-inflammatory properties for aquaculture diets. We intent to strengthen the knowledge of molecular nutrition and fish health and its underlying fundamental mechanisms. Zebrafish are an established well-known model for intestinal homeostasis. Therefore, by using larvae, juveniles and adult zebrafish we will set-up a toolbox of read-out parameters to scientifically base the choices for novel and health-boosting food ingredients.

Results

We have developed a zebrafish inflammation model with saponin, which is an antinutritional factor, immersion. We also assessed that such inflammatory response is linked to a change in the microbiota composition in the zebrafish larvae and increase neutrophil presence in the zebrafish gut (López Nadal et al. 2018).

Zebrafish larvae Tg(mpeg1:mCherry/mpx:eGFPi114) exposed to 1 mg/ml saponin (right column pictures) in solution for 3 days displayed increased number of neutrophils (in green) but not macrophages (in red) compared to controls (left column pictures)
Zebrafish larvae Tg(mpeg1:mCherry/mpx:eGFPi114) exposed to 1 mg/ml saponin (right column pictures) in solution for 3 days displayed increased number of neutrophils (in green) but not macrophages (in red) compared to controls (left column pictures)

Furthermore we tested a brown algae fucoidan in our in vivo model to assess whether it can be used for validating novel feed components (prebiotics) (Ikeda-Ohtsubo et al. 2020). We have also gathered and interpreted most of the knowledge about pre- and probiotics in zebrafish research and revised the experimental designs used as well as the mechanisms involved in the gut-related immunity and the host-microbe interaction (López Nadal et al. 2020).

Publications