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

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USE OF SOY BASED PRODUCTS IN PRACTICAL DIETS FOR WHITE SEABASS,
Atractoscion nobilis AND CALIFORNIA YELLOWTAIL, Seriola lalandi
Dave Jirsa*, Allen Davis, Mark Drawbridge and Kevin Stuart
Hubbs-SeaWorld Research Institute
San Diego, CA 92109 USA
djirsa@hswri.org
White seabass (WSB), Atractoscion nobilis and California yellowtail (YT), Seriola lalandi are two of the top five candidate
species for ocean farming in southern California. Hubbs-SeaWorld Research Institute (HSWRI) has maintained spawning
populations of WSB since 1984 and YT since 2003. WSB aquaculture has been directed primarily toward stock enhancement,
while YT is considered more for its commercial potential. Both species are carnivorous and are currently reared on standard
commercial diets whose protein ingredients have not yet been “optimized” relative to long-term sustainability issues associated
with fish meal and oil.
This project is consistent with several of the goals of the Plant Products in Aquafeed (PPA) Working Group Strategic Research
Plan, but most specifically to “establish standardized research approaches and protocols for systematic evaluation of plant
feedstuffs across carnivorous fish species”. Furthermore, recent California law (SB 201) states “To reduce adverse effects on
global ocean ecosystems, the use of fish meal and fish oil [in aquaculture] shall be minimized. Where feasible, alternatives to
fish meal and fish oil, or fish meal and fish oil made from seafood harvesting byproducts, shall be utilized . . .”
The specific goals of this project are to (1) develop and validate an open formulation for the WSB and YT based on modifications
of the existing commercial diet being fed to WSB and YT and (2) evaluate the response of WSB and YT to a diet with
increasing levels of soy protein concentrate as a replacement for fish meal, and (3) evaluate the response of WSB and YT to a
diet with increasing levels of soy oil as a fish oil replacement while keeping other nutritional factors constant.
The first trial is designed to validate our protocols and make a preliminary assessment of the species’ reaction to soy products
in the diets. For the first trial, WSB were stocked into 60L tanks supplied with 18°C recirculated seawater at a size of 3.5g and
fed 4-6% body weight daily. YT were stocked into 1000L tanks supplied with 21°C seawater at a size of 5.5g and fed 6-8%
body weight daily. Fish were weighed bi-weekly. After four weeks WSB weighed 7.3 – 8.2g and YT 18.7 -26.1g. Preliminary
results indicate that the open formulation feed performs similarly to current commercial diet and there is considerable potential
for fish meal to be reduced using either soybean meal and/or soy protein isolate.