2012 Annual Report 1a.Objectives (from AD-416): Develop an in-vitro test to determine the presence of intestinal enteritis in rainbow trout. 1b.Approach (from AD-416): Rainbow trout fingerlings (average 9 grams per fish initial weight) will be fed diets varying in type and level of soybean meal. After 16 weeks of feeding the experimental diets, blood from 40 fish in each tank will be sampled. Plamsa will be tested for LDH, bilirubin, immunoglobin, fibrinogen, ATPase. Plamsa will also be evaluated using NMR by EWOS Innovation in Norway. 3.Progress Report: This is the final report for this project. This research links to the parent project through objective 3. Experimental diets containing different levels of soybean meal were formulated, manufactured and fed to rainbow trout for 12 weeks. Sub-samples of five fish from each tank were euthanized and sampled at 4 week intervals. Blood samples and the distal section of the small intestines were collected in order to determine the presence or absence of enteritis using a standardized histological evaluation. Blood samples were evaluated using rapid blood test analyzer in Montana and by Nuclear Magnetic Resonance in Norway. Correlations between blood chemistry and histological examinations will be made. Development of a method that eliminates the need for histology to determine the presence or absence of soy caused intestinal enteritis will greatly enhance the development of plant based feeds for fish.