Forsøksdyr: FoN Zf Infection

Godkjenningsdato 21.12.2018

The SFI "Foods of Norway" is developing experimental diets for farm animals and fish using sustainable local feed ingredients to reduce the reliance on imported feed ingredients. These experimental diets contain varying levels of protein derived from yeast that are produced using sugars and other nutrients derived from natural resources such as wood, grass and seaweed. One goal of Foods of Norway is to evaluate the effect of novel, yeast-based diets (partially or totally replacing currently used plant ingredients) on preformance and health of monogastric animals, including fish. Further, to evaluate the potential of certain yeast strains to promote resistance to bacterial infections.

The purpose of this pilot project will be to determine the potential of laboratory fish (zebrafish and medaka) as in vivo models for the rapid screening of experimental diets following bacterial infection. Infection protocols for Aeromonas salmonicida and Aeromonas hydrophila in zebrafish and medaka will be compared and a single low mortality infection protocol selected for the assessment of bioactivity of experimental diets.

The ability of the selected in vivo infection model to detect bioactivity of experimental diets will be tested. The diets to be tested are: up to 5 different low-protein diets with different yeast-based ingredients, in comparison with a fixed reference diet. To screen the diets, laboratory fish will be fed for 8 weeks beginning at 8-12 weeks of age, and will be challenged with a bacterial infection after 4 weeks, after which survival rates will be determined. Surviving fish will be sacrificed at 2 and 4 weeks after infection. The experiment will be terminated at 4 weeks post infection. The size and weight of all sampled fish will be determined, and their tissues analyzed for signs of infection (including by morphological analysis of histological sections, and qPCR analysis of a panel of molecular markers of the specific bacterial strain).

The number of fish included in this pilot study has been kept to a minimun (total 500) that is expected to account for individual variation and give results that can be used to design future studies. The results of this pilot experiment will be used to minimize the number of animals included in future studies. It is expected that the effective screening in laboratory fish will greatly enhance the identification of the health-related bioactivity of diets. The benefit will be that fewer diets (but with a known bioactive profile) are tested in production animals and fish. This will reduce the number of large animal experiments that need to be performed.