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

A STANDARD GENETIC STOCK OF RAINBOW TROUT FOR RESEARCH STUDIES
Ken Overturf* and Ronald Hardy
USDA-ARS
Hagerman Fish Culture Experiment Station
3059-F National Fish Hatchery Road
Hagerman, Idaho 83332 USA
Ken.Overturf@ars.usda.gov
Research studies comparing similar diets, ingredient substitution or effects of nutrient supplementation often exhibit significant
differences in the response of fish compared to results from similar studies. Furthermore, researchers attempting to replicate
specific physiological signs associated with antinutritional factors in certain feed ingredients found by other researchers are
often unable to duplicate the original findings under their laboratory conditions. There are many explanations given for such
different findings, including differences in rearing conditions, such as water temperatures and flows, differences in feeding
level or frequency, or method of data analysis. However, in published discussions from several of these studies the authors suggest
that the differences reported in their findings, when compared to what others had found, could be do to genetic differences
between stocks of fish. Most rainbow stocks used in research studies come from eggs purchased from commercial suppliers,
local broodstock, academic stocks, or wildlife management facilities. One solution to this potential problem is to make eggs
from a single, defined stock of rainbow trout available to researchers. Through funding made available from the US Soybean
Board, the University of Idaho and USDA/ARS are generating a research stock of rainbow trout whose makeup will consist
of a cross between two commercial strains. The parent strains for this stock will be subjected to photoperiod manipulation so
that fish can be spawned at up to four different times per year, making eggs available to researchers throughout the year. Initial
stocks were received in the spring of 2007 and the first crosses will be generated beginning the fall of 2009. These stocks of
fish should prove a valuable resource for researchers by limiting differences detected in studies thought to be due to variation
in the genetic background of rainbow trout used in feeding trials
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