282 Dynamics of Mitochondrial Adaptation and Energy Metabolism in Rainbow Trout (Oncorhynchus mykiss) in Response to Sustainable Diet and Temperature

Abstract

Abstract Impacts of plant-based ingredients and temperature regimens on energy metabolism and mitochondrial function in rainbow trout were investigated. Two hundred and eighty-eight fish weighing 45.6 ± 0.05 g (average ±SD) were evenly allocated to 24 tanks. For 150 days, fish were fed four isocaloric, isolipidic and isonitrogenous diets containing 40% crude protein and 20% crude lipid and formulated as 100 % animal-based protein (AP) and a blend of 50% fish oil (FO) and 50% camelina oil (CO), 100% AP and 100% CO, 100% plant-based protein (PP) and a blend of 50% FO and 50% CO or 100% PP and 100% CO at 14 or 18 °C twice daily. Main effect of diet or temperature, or diet x temperature interaction did not significantly affect percentage weight gain (PWG), condition factor (CF) or specific growth rate (SGR) (P > 0.05), but diet significantly impacted both feed efficiency (FE) and feed intake (FI). Only temperature had a significant impact on whole-body ash content. Furthermore, temperature did not influence protein efficiency ratio (PER), lipid efficiency ratio (LER), protein productive value (PPV), energy productive value (EPV), and lipid productive value (LPV); however, diet had significant major effects on PER, LPV, and PPV (P < 0.05). Temperature regimens induced increased activities of mitochondrial complexes I, II, III, IV, V, and citrate synthase in all tissues (liver, muscle and intestine). Similarly, dietary composition affected the same enzyme activities except complex III activity. Diet x temperature interaction impacted citrate synthase activity at 18 °C. Overall, comparing partial to full dietary substitution of FO with CO, partial dietary replacement showed similar effects on complex activities. Hence, aquaculture could economically benefit from a 40:20 plant protein/lipid dietary composition.