Canadian research has success with pilot scale processing of wheat distillers dried grain with solubles (DDGS), yielding different fractions targeted for monogastric and ruminant animal feeding.
The low cost dry fractionation of DDGS has prompted research into digestibility and nutrient attributes of this product.
"During ethanol production, the starch in wheat grain is broken down and the sugars fermented to ethanol for mixing with gasoline. The remaining protein and fibre concentrate about three times in DDGS compared to wheat grain," says Eduardo Beltranena, feed research scientist with Alberta Agriculture and Rural Development.
As long as the DDGS are gently dried and not scorched, the protein in wheat DDGS (38 to 40%) has good feeding value for livestock.
However, the high fibre content of DDGS (35%) limits its nutrient utilization by monogastric animals, because they lack a rumen full of bacteria like cattle do to digest the fibre for them.
"We had to come up with a way of enriching the protein and reducing the fibre to effectively increase utilization of this ethanol co-product by poultry and swine.
“We had to do so at low cost, in an environmentally friendly manner, and keeping in mind that prairie ethanol plants have been built already and are unlikely to modify their process" says Beltranena.
"Using readily available particle size and weight separation equipment we produced fractions ranging from 29% protein and 36% fibre for ruminants to 49% protein, but only 18% total dietary fibre for monogastric animals.
"With little investment, existing ethanol plants could now scale-up this technology to differentiate their DDGS as a plant back-end process instead of changing their processing.
“Having species-targeted DDGS would increase use of this ethanol co-product by more animal species than just cattle, and diversify the market opportunity for the ample supply of prairie wheat DDGS."
Fractions feeding trials with broilers, trout and growing pigs are now being carried out in collaboration with the University of Saskatchewan and University of Alberta.