Degree:Master of ~nvironmentai ToxicologyTitle of Project:The effects of diet composition and ration on biotransformation enzymes and stress parameters in rainbow trout, Oncorhynchus mykiss. PARTIAL COPYRIGHT LICENCEI hereby grant to Simon Fraser University the right to lend my thesis, project or extended essay (the title of which is shown below) to users of the Simon Fraser University Library, and to make partial or single copies only for such users or in response to a request from the library of any other university, or other educational institution, on its own behalf or for one of its users. I further agree that permission for multiple copying of this work for scholarly purposes may be granted by me or the Dean of Graduate Studies. It is understood that copying or publication of this work for financial gain shall not be allowed without my written permission. Title of ThesislProjecff Extended EssayThe effects of diet composition and ration on biotransforrnation enzymres and stress parameters in rainbow trout, Oncorhynchus mykiss.Michelle Dayna Morrow (name) ABSTRACTNutritional quality and quantity play significant roles in the amount of energy an animal assimilates and in the distribution of that energy. Furthermore, energy is allocated in a hierarchical fashion beginning with basal metabolism and then successively to other physiological processes depending on other energetic requirements of the animal. To date, little information exists on the effects of diet and ration on the stress response and detoxification system in fish. Therefore, the purpose of this study was to measure the effects of dietary composition and ration on the biotransformation and stress response systems in juvenile rainbow trout.Juvenile rainbow trout (Oncorhynchus mykiss) were fed one of three isoenergetic diets varying in protein (35 to 55%) and lipid content (8 to 18%), at full satiation or partial ration for 6 weeks in order to investigate the effects of diet on baseline stress parameters and biotransformation enzyme activity. Growth was highest in fish fed low protein, high lipid diets at both ration levels and was highest overall in fish fed to satiation. Stress indicators, including plasma lactate, glucose and cortisol concentrations were not significantly affected by dietary treatment or ration. Basal biotransformation enzyme activity, including glutathione S-transferase (GST) and ethoxyresorufin 0-deethylase (EROD) activity, were also unaffected by dietary treatment. Fish exposed to the biotransformation enzyme inducer 13-napthoflavone did not exhibit an alteration in stress indicators or GST activity; however, EROD activity was increased (87 to 210-fold) in fish receiving all diets and rations demonstrating the importance of this system even under limited energy intake.The results of the present study indicate that, unlike mammals, fish may be more recalcitrant to different levels of ingestion (above maintenance ration) of isoenergetic ACKNOWLEDGEMENTS