Feed additives help agriculture and the environment
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.
ARS researchers Ed Mullaney and Jaffor Ullah have
designed hard-working phytase
enzymes that help chickens digest more of the phosphorus found in their
While phosphorus is a necessary mineral that helps
make up the DNA in all animals, excess phosphorus loads - in the form of manure
- can contribute to pollution.
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
Twenty years ago, Mullaney and Ullah were the first to
characterise a natural, fungal-based enzyme - called phytase - which 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
Southern Regional Research Center in New Orleans.
previous work, the scientists have now created new and improved enzymes
specially suited for working in the stomachs of chickens and swine. They
realised 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
Read more about the research in the July 2006 issue of Agricultural Research magazine
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