Forsøksdyr: Use of zebrafish as a model to evaluate possible preventive and healing properties of seaweeds products regarding gut health in monogastric animals including humans

Godkjenningsdato 04.12.2018

Godkjenningsperiode 14.01.2019-01.03.2019

The objective of this trial is to investigate possible health effects of seaweed products in the feed of monogastric animals by applying zebrafish as the model organism. The project aims to evaluate how dietary inclusions of whole seaweed products may have an impact on prevention of and recovery from diseases such as gut inflammation and tissue damage. Two different challenge assays will be performed, including exposure to a high cholesterol diet expected to activate inflammatory reactions in the zebrafish gut, although not considered as causing any welfare challenges, which needs special measures, and clipping of the tail fin. Fin clipping is a common marking procedure in commercial fish production and a well-developed model in zebrafish, which within 7-14 days heals the wound and regenerates a new fin. Some discomfort is expected 24 hours after the procedure.

The trial is part of a large ongoing project, PROMAC, which aims to found a basis for utilization of Norwegian seaweeds as a source of nutrients and bioactive components for humans and animals. Seaweeds are a renewable and non-traditional raw material that could be used to face some of the local and global challenges with limited feed resources. There are indications that seaweeds may have health-promoting effects in both humans and production animals. Zebrafish was chosen as the model animal for this study as some of the seaweed products produced in the PROMAC project are available only in very limited amounts. Zebrafish is further a well-recognized and acknowledged animal model for investigation of immune and other health-related functions in monogastric animals, including humans. Their small size and rapid growth allow relatively short-term investigation without demanding large amounts of research material, i.e. conditions which are very favorable compared to similar studies in land animals, including humans. 900 wild-type zebrafish will be sacrificed for this study.

The study will address effects of seaweeds on the immune and regenerative response of monogastric animals, and at present there is no suitable in vitro model which can replace an animal model, due e.g. to the complex interaction that takes place between the host, microbiota and environment. The present study has been designed to minimize the number of animals to be included. Feeding trials, due to large variation between individuals regarding feed intake, have inherited fairly large variance regarding most biological effects. The experimental animals will be kept in a standard and approved facility with well trained staff. To ensure the welfare of the fish, there will be frequent observation of the fish for possible illness and behavioral changes. Sampling will be performed on euthanized fish. Before fin clipping, the fish will be anaesthetized. Fish will be kept in recovery tanks until swimming control is recovered completely before transferred back to experimental tanks, and monitored every 2 hours for the first 8 hours and afterwards three times per day. If the fish shows symptoms of pain or discomfort such as erratic swimming behavior or evident lesions the fish will be euthanized.