Flocks of chickens fed a hybrid strain of corn produced manure with 41 percent less phosphorus than normal in an experiment conducted by the University of Delaware.
The findings have significant meaning for farmers, who are under pressure to reduce the amount of phosphorus, a vital soil nutrient, spread as fertilizer. Phosphorus runoff is widely blamed for water pollution, fish kills and outbreaks of Pfiesteria piscicida, a toxic microorganism.
Several grain companies have licensed the gene needed to make the new variety of corn, which might be on the market within six months.
The issue of chicken manure as a farm nutrient is particularly sensitive on the Delmarva Peninsula, which includes Delaware, part of Virginia and Maryland’s Eastern Shore. The home of many chicken houses, which provide the area’s significant farming community with the manure, the region is also home to a fishing fleet that depends on clean water.
In the university study, more than 8,200 male broilers were fed a mix of diets using the corn hybrid. The hybrid has a more digestible form of phosphorus, which chickens need to meet growth and health requirements.
Some of the chickens were also fed an enzyme that aids the digestion of phosphorus, meaning less phosphorus passed through the chicken and into the droppings.
“The total phosphorus in grain remains the same,” said George Malone, a poultry extension specialist with the University of Delaware. “But, the amount of phosphorus available for digestion by the chicken increases.”
Manure from those broilers fed both the enzyme and the corn hybrid had 41 percent less total phosphorus than normal. But better yet, he said, was an 82 percent reduction in water-soluble phosphorus by those birds.
The decrease in soluble phosphorus is significant, he said, because soluble phosphorus passes easily through soil and into water.
This study comes nearly two years after the U.S. Department of Agriculture developed the corn hybrid in laboratory experiments by Victor Raboy, a geneticist with the USDA’s Agriculture Research Service in Aberdeen, ID.
“A 41 percent reduction in total phosphorus is a pretty big deal,” Raboy said.
The University of Delaware worked with the USDA and several poultry companies to test the chicken feed on a scale larger than available in a laboratory.
But the phosphorus-reducing chicken feed has yet to be produced on a commercial scale involving thousands of tons of corn, said Spangler Klopp, corporate veterinarian for Townsends, a Delaware-based poultry producer.
The low-acid corn plant must also be tested to determine whether it has desirable yields and resistance to pests and disease.