February 15-18, 2009 Washington State Convention Center Seattle ...

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SELECTIVE BREEDING AND A NON-FISH MEAL DIET FOR RAINBOW TROUT
Oncorhynchus mykiss: A CLOSER LOOK AT FAMILY CX-70
Scott Snyder*, Gibson Gaylord, Ken Overturf, Frederic Barrows and Ronald Hardy
Hagerman Fish Culture Experiment Station
University of Idaho and USDA-ARS
3059-F National Fish Hatchery Road
Hagerman, ID 83332 USA
scott.snyder@vandals.uidaho.edu
Studies have shown variation in growth performance between animal strains can be accounted for by either increased feed
intake or altered metabolic efficiencies. This variability in nutrient retention efficiency allows for selective breeding programs
that can effectively create lines of rainbow trout (RBT) better able to utilize plant-derived nutrients. A RBT brood stock selection
program exists at the Hagerman Fish Culture Experiment Station (HFCES) with this goal. By obtaining founder stock
(USFWS Arlee, CSI-House Creek) green eggs and milt, and f 3 ’s of the Arlee (A) x House Creek (HC) line, we simultaneously
reared 5 families of fish; founder stock (A x A, HC x HC), a mimic of the original f 1 ’s (A x HC, HC x A) and f 3 ’s (CX-70) of
this RBT line for the purpose of conducting a growth trial to identify the changes in fish growth after 2 generations of selection
due to plant-derived nutrient selection pressure.
Utilizing a 5x2 factorial design containing 5 families of fish, 2 diets and 3 replicates per treatment, thirty 145-l flow-through
tanks were randomly assigned a treatment replicate and stocked with twenty 40-g fish each. Each tank was supplied with 15 °C
spring water with a flow rate of 12-lmin -1 . Diet 1 (Fish) (47%CP, 5400 cal/g GE, 15% CF) derived all of its protein from fish
meal and diet 2 (Plant) (44%CP, 5400 cal/g GE, 15% CF) derived all of its protein from a blend of plant products and serves
as the selection diet in the selection program at HFCES. Fish were fed to apparent satiation 2 times per day, 6 days per week
for 12 weeks.