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computer-generated image of a phytase molecule enables researchers to make
changes to improve the enzyme. Click the image for more information about
Feed Additives Help Agriculture and the
Environment By Erin Peabody July
Talk about killing two birds with one stone. Researchers with the
Agricultural Research Service (ARS) have
designed feed supplements for poultry and other farm animals that not only
boost nutrition, but also reduce the amount of potentially harmful phosphorus
escaping into the environment.
Ullah have designed hard-working phytase enzymes that help chickens and
swine digest more of the phosphorus found in their plant-based diets. While
phosphorus is a necessary mineral that helps make up the DNA in all animals,
excess phosphorus loadsin the form of manurecan contribute to
Unnaturally high levels of phosphorus seeping into rivers and oceans
trigger massive algal blooms that steal oxygen from the water as they
decompose. Depleted oxygen stores send shockwaves through marine ecosystems,
causing large numbers of fish and other organisms to die off.
Twenty years ago, Mullaney and Ullah were the first to characterize a
natural, fungal-based enzymecalled phytasewhich could improve
animal nutrition, save on feed costs and reduce phosphorus losses from farms.
Mullaney, a geneticist, and Ullah, a biochemist, both work at the ARS
Regional Research Center in New Orleans, La.
Building on previous work, the scientists have now created new and
improved enzymes specially suited for working in the stomachs of chickens and
swine. They realized that phytase is an impressive catalyst for breaking down
the tied-up phosphorus in animals' plant-based diets, but its performance isn't
optimal in the microenvironments typical of many animal stomachs.
To get around this obstacle, the researchers made over the enzyme on a
molecular scale. Its new look is making all the difference. In fact, Mullaney
and collaborators discovered that swine fed the redesigned phytase additive for
just five weeks gained 13 percent more weight than swine fed the original
enzyme. And if the animals are absorbing more phosphorus, they are excreting
less in their manure.
about the research in the July 2006 issue of Agricultural Research
magazine, available online at:
ARS is the U.S. Department of
Agriculture's chief scientific research agency.