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 24.01.2018

A large ongoing project, PROMAC, financed by NFR, aims to found a basis for utilization of Norwegian seaweeds as a source of nutrients and bioactive components for humans and animals which. At present, relevant knowledge is very limited. The study described herein will be the second of two employing zebrafish as a model animal, planned under PROMAC. The first study (FOTS ID 11316) was a screening experiment with several seaweed products at two dietary inclusion levels. Based on the results of the previous study a follow-up study is necessary using the most promising products and inclusion levels, addressing mechanisms underlying the immunological effects observed in the first study to reveal whether they are beneficial or detrimental. The experiment has three Tasks.

Task 1: Effects on normal functions. A 4 week feeding period with 6 experimental diets: two reference diets and 4 containing seaweed products will be made. Six replicate tanks, each with 25 fish will be used. Six of these tanks will be stocked with wild-type AB zebrafish line. At the termination of the feeding period, three fish will be sampled from each tank for the study of effects on intestinal structure, digestive functions, expression of functional and immunological genes in the gut mucosa, as well as gut microbiota. The sampling of three fish per tank in this stage will be sufficient for detection of important differences between diets for most variables, according to experience from our previous studies with zebrafish. For some variables pooling of samples is necessary to obtain sufficient material for the functional analyses.

Task 2: Prevention of inflammation. Small batches of all the experimental diets will be supplemented with cholesterol. Cholesterol has been shown to activate inflammatory mechanisms in zebrafish gut. Modulation of the stimulating effects of cholesterol is, therefore, indicating possible beneficial effects of seaweed components. All fish will be fed one meal of these diets and thereafter continued on their normal diets. Samples will be collected from these fish after 4h, 24h and 7 days from three fish per tank. Tissue samples will be examined regarding histology, gene expression profiling, microbiota characterisation and immune function.

Task 3: Effects on tissue regeneration. The remaining fish will be tail clipped, fed one meal with the cholesterol-enriched diet, and thereafter continued on their diets for one week. Fin clipping is a common marking procedure in commercial fish production and well-developed model in zebrafish which within about 7 to 14 days heals the wound and repairs the fin completely. Samples will be collected at three time points, i.e. 4h, 24h and 7 days after clipping from three fish per tank. Tissue samples will be examined regarding histology, gene expression profiling, microbiota characterisation and immune function.