Soy fish food could open markets for South Dakota farmers
BROOKINGS – Research into alternative fish feed could jump-start the fish-farming industry in South Dakota and provide a new market for soybean farmers, proponents hope.
“Our target here, our aim, is to reduce operating costs by producing these novel soy ingredients that can replace fish meal,” said Michael Brown, a professor of fishery sciences at South Dakota State University.
Brown and his collaborators are halfway through a three-year, $1.7 million research project sponsored by the South Dakota Soybean Research & Promotion Council to develop these alternative feeds.
Their goal is to identify a production process by which soy-based feed can replace some or all of the protein in the diets of fish raised in public and private hatcheries.
“Quality feed ingredients are going to be very important over the next couple decades,” Brown said.
That’s because most of a commercial fish farm’s budget is spent on fish meal based on marine protein – anchovies, herring and other ocean stock that can cost up to a dollar a pound. Part of this expense is because of the high cost of importing the meal from foreign countries – China, say, or Peru.
That goes for the finished product, too. China exports about 60 percent of all aquaculture products in the world, Brown said, and the U.S. imports about 85 percent of the fish and shellfish it eats.
And as more citizens in China and other fish exporters move into the middle class, Brown predicts, exports will slow, leaving an opening for domestic fish farms.
There’s also the basic fact that the earth’s human population – and its protein needs – are growing, even as stocks from over-exploited marine fisheries flat line or decline. The U.S. Department of Agriculture estimates that global demand for seafood will increase 70 percent in the next 30 years.
“We’ve maximized the use of the marine ecosystem for the production of fish,” Brown said. “The ecosystems are stable or over-exploited. What’s going to fill that void? It’s got to be aquaculture.”
For these and other reasons, Brown and his colleagues see an opening to develop a domestic fish-farming industry, maybe even in South Dakota. And all those fish need to eat, so why not find a locally grown feed?
“We have water and food and labor,” Brown said. “That’s basically it – we have all three things that would allow us to develop an industry in the state.”
In what is perhaps a sign of how close the technology is to commercialization, Brown and his primary collaborator Bill Gibbons, a microbiologist at SDSU, are advising Prairie Aquatech, a startup backed by the Sioux Falls venture capital firm South Dakota Innovation Partners.
“We’re clicking along,” Brown said. “Every day is a new day. … But within the next year and a half, we should be pretty well down the pike.”
Despite the costs, aquaculture has grown at an 8 percent clip in the past two decades, Brown said.
Not much of that growth has come in the U.S., and the industry is practically nonexistent in South Dakota. USDA could identify only seven commercial fish farms in the state in 2006, the last year for which federal aquaculture data were available.
Four of these are Hutterite colonies raising tilapia. A private fish farmer in the Black Hills does about 400,000 pounds of rainbow trout to supply restaurants. By comparison, a large fish farm in a southern state might raise 100,000 tons per year.
Brown’s main guinea pigs at his 174-tank lab in Brookings are yellow perch, though he works with other, mostly freshwater, species as well.
For instance, he co-wrote a paper with Mike Barnes, manager of the McNenny Fish Hatchery in the Black Hills, and two others investigating the possibility of shifting state-bred trout and salmon onto a soy diet.
The researchers were able to substitute a diet that contained up to about 60 percent fermented soy meal before they started to see weight drop. The research was published this year in the Open Journal of Animal Sciences.
Barnes cautioned that the results of the experiment are preliminary – they didn’t even try to make the diets the same with regard to total energy composition, for instance. But follow-up studies have been promising.
This winter, researchers will feed the fish a soy diet and then examine their intestinal tissue at a cellular level to determine the level of irritation.
“If we can eliminate those (irritants), the sky’s the limit,” Barnes said.
If soy could be substituted for animal protein without seeing a drop in trout weight, that could mean a significant savings for taxpayers who buy the feed for public hatcheries.
“We’re hoping they can take some of this research and keep the cost of fish food from rising dramatically,” Barnes said.
Whether the state adopts a soy feed will depend partly on who wins the contract. Right now, it’s Nelson and Sons of Utah, one of the closest suppliers. But that company recently was bought by the multinational firm Skretting, which has a wider supply.
Broadly speaking, the challenge facing the researchers is twofold. First, scientists need to find a soy-based feed that has enough of the specific proteins each species of fish needs to thrive.
“Chickens are chickens, but fish aren’t just fish,” Brown said. “There are 12,000 species, and their nutrient requirements vary quite a bit.”
And as some compounds in pure soy meal irritate fishes’ digestive systems, the researchers are trying different processing methods to filter them out – heat, solvents and fermentation.
They’re also trying to find a way to make the soy pellets attractive to fish that are used to eating other fish.
“You can have a nutritionally complete diet, at least on paper, but when you feed fish that diet, they have to find it palatable,” Brown said.
On the farming side, commercializing a specialty crop geared toward aquaculture markets is promising but poses its own set of challenges, said Doug Hanson, who is on the South Dakota Soybean Association Board.
One protein-rich strain that would be ideal for aquaculture is being developed by eMerge Genetics, a Des Moines, Iowa, company that markets soybean varieties that haven’t been genetically modified.
This year, Hanson tried some of the eMerge beans on 20 acres of his farm near Elk Point and said they did about as well as his conventional crop. He didn’t notice a yield drop.
“And that’s what the farmer’s going to look at,” he said. “If there’s a yield drag with a specialized crop, he’s going to be a little reluctant to plant it.”
Specialty beans also would have to be processed separately from conventional varieties, which could pose a logistical challenge.
All told, though, he’s optimistic about this potential market.
“If aquaculture keeps growing like it has been worldwide, it will be a nice boost – not just for South Dakota farmers but for all farmers,” he said.