...From the pages of Agricultural Research magazine
ForumTrout Research Makes a Splash!
A tiny chip, slipped just beneath the skin of your dog or cat, serves
as a reliable identifier if your pet should stray. Staffers at veterinary
offices or animal rescue centers can use the information embedded in
the chip to help get your pet back to you.
But who would outfit a rainbow trout with its own silicon-chip identifier?
In fact, giving a silvery trout its own high-tech name tag is a routine
procedure at the ARS aquaculture
research laboratories described in articles beginning on page 4.
Our geneticists are studying these experimental fish to learn more
about the information locked inside trout genes. These genes, for example,
may contain the sequence, or code, that enables certain trout to pack
on proportionately more muscle (the tender flesh that we eat) faster
than other trout. The little chips allow scientists to accurately identify
who's who among a tankful of lively trout. That way, the researchers
can more easily track inheritance of this or other prized traits. Stable
inheritance of valuable traits is essential to breeding superior trout
Other genetics research with trout may open a new market for growers
of oats, barley, and perhaps other grains. Here's how: We're determining
whether selected trout have a gene-derived ability to grow as quickly
on grain-based feeds as they do on conventional feeds made with ocean
Our pursuit of this trait is somewhat like trying to make a vegetarian
out of a carnivore. Why attempt that? Because shifting to grain-based
feed should cut production costs and ensure that we don't inadvertently
overfish the world's oceans.
The secret to other valuable traits also lies within trout genes. That's
why we're intent on deciphering the structure and function of all the
genes in rainbow troutwhat's known as the trout genome. Information
about the structure of a length of trout genetic materialDNAcan
be compared to sequences discovered in stretches of other species' DNA.
Our scientists, and investigators from around the world, share such
sequences by posting them on computerized, publicly accessible genome
Once fish geneticists find a structure that matches that from a trout,
it's possible that the genes' functions may also match. That's true
even among forms of life as different as a turnip and a trout. Using
genome databases to zero in on such similarities speeds and simplifies
the task of pinpointing the precise role of each trout gene.
The ability to probe the genes of organisms throughout nature is an
outgrowth of DNA discoveries made 50 years ago this year by James Watson
and Francis Crick. Our modern-day sleuthing of rainbow trout genes should
be invaluable in solving production problems inherent in raising not
only this fish, but also its salmonid relativesbrown trout, brook
trout, Pacific salmon, and Atlantic salmon. The work, for instance,
should be helpful in the new Atlantic salmon research that we will begin
in Maine at what will become the ARS National Cold Water Marine Aquaculture
In all, our gene-based studies should help America's fish farmers cut
production costs, remain good environmental stewards, and meet the growing
demand for fresh fish.
Excellent suggestions and recommendations for the salmon and trout
studiesand for our other aquaculture investigationswere
provided by fish ranchers, researchers, and others who participated
in a Joint National Aquaculture Program Planning Workshop, held in 2002
in St. Louis, Missouri. We'll use these ideas to update our National
Program. We've posted highlights of the workshop on the World Wide Web
at www.nps.ars.usda.gov. Once
you're on the web site, click on "Aquaculture (#106)," then
click on "National Program Planning Workshop."
This fall, as co-hosts of the United States Trout Farmers Association
2003 Annual Meeting, we'll have a new opportunity to make sure we're
tackling growers' most troublesome problems.
Next year, we'll get additional ideas and feedback from colleagues
convened as part of our agency's new scientific quality review system.
Agricultural Research, May 2002, p. 2.) This in-depth assessment
will cover all aspects of our aquaculture program.
Trout and salmon are good for you. They are high in protein and rich in healthful omega-3 fatty acids. Our research will help guarantee that these and other farm-raised fish remain plentiful and affordable for you to enjoy.
Lewis W. Smith
"Forum" was published in the June 2003 issue of Agricultural Research magazine.