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A Soluble Solution

St. Paul, Minn. – Baby pigs may soon be chowing feed fortified with ethanol-processing leftovers. And the diet won’t contain animal byproducts or antibiotics that are facing increasing consumer scrutiny.

Recently completed baby pig feeding trials at the University of Minnesota show favorable results using ethanol coproducts – a vegetable-based alternative to antimicrobial and porcine blood plasma products that are the gold standard for today’s swine rations.

“These findings should calm some food-safety and health concerns and add value to ethanol

plants,” says Jeff Knott, a U of M animal nutrition graduate student who conducted the feeding

trials headed by swine nutrition professor Gerald Shurson.

Diseases such as BSE (commonly called “mad cow disease”) have amplified concerns about using

animal byproducts such as blood plasma. And some consumers and scientists are concerned that

overusing antimicrobials in animals could promote bacterial resistance to antibiotics. Finding

ag-based alternatives that perform to the same standards would be a winning solution.

Knott says as far back as the 1940s and 50s, research was done on distiller’s solubles’ unexplained effect on livestock growth. The solubles are solids left in water after soaking corn during the ethanol-making process. Often the solubles are sprayed back onto distiller’s grain – another ethanol coproduct – and fed to livestock.

Past research shows that solubles hold promise, but they can be difficult to handle. Wet solubles – only about 35 percent solid matter – tend to bind and plug equipment.

Before the new solubles trials commenced, the U of M animal science and the food science and

nutrition departments developed a patent-pending process to spray-dry the solubles.

Three superior products were developed as a result: spray-dried distiller’s solubles, cream from

yeast byproduct and residual solubles – the syrupy material left after separating liquid from wet

mash, then drying the product to a solid form. The products were blended into baby pig diets and

compared to feeds containing combinations of porcine plasma and antimicrobials. Knott examined

the feed supplement’s effect on animal growth, feed intake, feed conversion, intestinal health

and immune system.

Seven different test groups were fed various diet combinations for 10 days after weaning. Then

all the pigs were fed the same diet. Knott found the ethanol coproducts yielded comparable or

superior results to plasma and antimicrobials.

“It’s not a bad thing that there weren’t statistical differences (between the ethanol and animal

byproduct),” Knott says. “We found that (ethanol) coproducts are effective in maintaining animal

performance when plasma and antimicrobials are taken out.”

“With the size of the swine industry in Minnesota and the movement away from blood plasma and

medications in pig diets, this could be huge,” says Alan Doering, AURI technical services

specialist. “Just about every ethanol plant is looking for ways to add value to their distiller’s


Knott says further nutritional research could lead to including distiller solubles coproducts in

poultry, pet or even aquaculture diets.

The economic pay-off could be enormous, Knott says. “Wet solubles are worth about $10 a ton.

Plasma and antimicrobials are expensive ingredients in swine diets. We’re converting a

lower-value item into a value-added product, plus it’s a vegetable-based alternative the industry

is looking for.”

The solubles study is among numerous projects undertaken by AURI and the Minnesota Corn Growers

to investigate new uses for distiller’s grains and other corn-processing coproducts.