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 from sugars and other nutrients derived from natural resources such as wood, grass and seaweed. The goal of Foods of Norway is to evaluate the potential of new, yeast-based diets to replace at least partially currently used soybean-based feeds, and to evaluate the anti-inflammatory properties reported for certain yeast strains. The purpose of this pilot project will be to compare the performance of 5 diets in zebrafish and determine the potential of zebrafish as a model for the rapid screening of experimental diets. The diets to be tested are: 1 standard high-protein zebrafish diet, 1 standard low-protein diet similar to salmon feed, 1 partially soy-based low-protein diet and 2 partially yeast-based low protein diets. It is expected that zebrafish fed soy-based diets will experience mild to moderate enteritis that will cause mild to moderate discomfort for the zebrafish eating the soy-based diets. Wild-type Zzebrafish (n=480) will be fed for 2, 4, or 8 weeks beginning at 6-8 weeks of age. Zebrafish sacrificed at these timepoints will be measured and weighed, gut morphology will be evaluated through histological analysis of tissue sections, and gene expression analysis will be performed by qPCR using a panel of molecular markers of inflammation and gut health. Based on the results of this pilot experiment, future studies of yeast-based diets in zebrafish will be designed accordingly to minimize the number of animals used in each study. It is expected that the effective screening in zebrafish 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.