JUST KEEP GILLING: DIETARY AND GENETIC STRATEGIES TO IMPROVE HYPOXIA TOLERANCE IN RAINBOW TROUT

The long-term goal of this research is to combine genetic selection strategies with feeding andhusbandry strategies in rainbow trout production in order to optimize key epigenetic mechanismsregulating growth and stress tolerance to enhance growth performance while selecting genetics fordisease resistance or fillet yield and relying less on marine resources in feeds.This project will clearly identify metabolic regulatory mechanisms and hypoxia-relatedpathways affected by key nutrients, methyl donors, to increase production and economic efficiency. Atwo-tier approach will be used to build on the existing genetic selection program at the National Centerfor Cool and Cold Water Aquaculture (NCCCWA, ARS, USDA, Leetown, WV) that has been selectingfor two traits independently, disease resistance and fillet yield. The disease resistant selected line wasrecently released to commercial fish operations (e.g., TroutLodge). Our specific objectives are to 1)determine how specific trait selection affects stress tolerance, 2) identify how maternal dietary cholineintake affects offspring growth potential, fillet yield, and stress tolerance, and 3) demonstrate howmaternal dietary choline intake interacts with maternal stress exposure to imprint offspring. To satisfythese objectives, we will test the following hypotheses: 1) genetic selection for performance-relatedtraits, like disease resistance or fillet yield, reduces hypoxic stress tolerance, 2) dietary choline intakeattenuates negative hypoxic stress effects on reproductive performance and offspring stress tolerance,and 3) maternal exposure to acute hypoxic events alters offspring hypoxia tolerance through maternalimprinting (epigenetics).