Illinois Study Confirms Glycerin as Feasible Feedstuff for Pigs

by 5m Editor
20 January 2011, at 12:00am

An increased interest in biofuel production and a growing need to find cost-effective livestock feedstuff alternatives has led University of Illinois researchers to further evaluate the use of glycerin in swine diets.

The study, led by University of Illinois (U of I) graduate research assistant Omarh Mendoza, was published in Journal of Animal Science and reports that swine diets may include up to 15 per cent glycerin and achieve similar performance to a conventional corn:soybean diet.

"Glycerin is not a new product, but little is known about its role as a feed ingredient for swine," said Michael Ellis, U of I professor in the Department of Animal Sciences. "Previous studies have shown variable results."

Glycerin is a feasible feedstuff for swine
Photo: Omarh Mendoza, University of Illinois

Glycerin is a major co-product of biodiesel production. This resulting liquid energy source is sweet and palatable, Ellis said. While it's more commonly used by humans, it has the potential for greater inclusion in livestock diets.

"We performed a standard feedstuff digestibility evaluation," Professor Ellis said. "We determined its energy digestibility and metabolizable energy value. We used this value to formulate diets in a controlled study here at the U of I Swine Research Center."

The study determined that glycerin could be fed up to levels of 15 per cent of the swine diet.

"We didn't test it at higher levels because the efficiency of use of the energy may decrease so we don't recommend using glycerin at levels higher than 15 per cent," he said.

Previous studies suggested that feeding glycerin could improve meat quality, Professor Ellis added. However, the U of I study revealed no effect of feeding glycerin on meat quality. The glycerin diet had comparable results to the corn-soybean diet.

Although glycerin looks to be a promising alternative, as with any feedstuff, it depends upon current market prices.

"Liquid glycerin has the potential for greater inclusion in swine diets if the price becomes more competitive than traditional feed ingredients. However, researchers say feed flow needs to be considered due to the physical characteristics of this ingredient."
Omarh Mendoza

"Glycerin has alternative uses beyond being used as a feed ingredient," Professor Ellis said. "It is available, but the demand for this ingredient sometimes causes it to be too expensive to use in a diet. But there are occasions when it's economically feasible to use. If the biofuels industry keeps growing, that could make it even more accessible in the future."

Aaron Gaines, co-researcher and Vice President of Production Resources & Operations at The Maschhoffs, said feed-flow issues need to be considered when using glycerin.

"Glycerin is available to the swine industry as crude glycerin," Dr Gaines said. "Crude glycerin is a viscous liquid, and dietary inclusion rates of five per cent or greater can result in feed flowability issues."

This article, 'Metabolizable energy content of refined glycerin and its effects on growth performance and carcass and pork quality characteristics of finishing pigs', was published in the Journal of Animal Science. Researchers included Omarh Mendoza, Floyd McKeith and Michael Ellis of the University of Illinois, and Aaron Gaines of The Maschhoffs, LLC.


Mendoza O.F., M. Ellis, F.K. McKeith and A.M. Gaines. 2010. Metabolizable energy content of refined glycerin and its effects on growth performance and carcass and pork quality characteristics of finishing pigs. J. Anim. Sci., 88:3887-3895.

Further Reading

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January 2011
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