Tests show glycerin comparable to corn

Brian Kerr, research leader in Ames, Iowa, who works
for the USDA Agricultural Research Service, said the crude glycerin was fed to
laying hens and swine while their metabolisms were analyzed. “Our goal was to
use [glycerin] as an energy source for swine and poultry,” he said. “You’ve got
to have energy for pigs and chickens to grow, as well as amino acids and other
items, and [glycerin is] used for growth and productive purposes.”

Although the crude glycerin was determined to be a viable
energy-creating feed, Kerr said the ever-fluctuating markets ultimately
determine its use. “Corn would be cheaper,” he said, referring to the present
situation. “When we started [testing], glycerin was 3 cents a pound. Corn at
that time was maybe 6 cents a pound.” However, now glycerin is 20 cents per
pound. “At 20 cents a pound, it’s too expensive as an energy source,” he said.

The testing consisted of energy-balance experiments that determined the
effect of carefully applied dietary treatments, which ultimately rendered a
metabolized energy number. “[We] feed them a known quantity of feed or test
ingredient, and then determine how much energy they have consumed from that diet
and how much energy has been excreted in the feces or urine to come up with a
metabolized energy number,” Kerr explained.

Crude glycerin is 85%
glycerin, 10% water and 5% salts, as opposed to refined glycerin, which is more
than 99% glycerin with no impurities. Refined glycerin can be used to make
pharmaceutical products.

Related folder:
Dossier AllAbout Bio Energy  

Related website:
Iowa State University  

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