June 20, 2006

Study says dietary fiber greatly reduces poultry ammonia emissions

Researchers at Iowa State University have found that increasing dietary fiber in the feed of laying hens can lower manure ammonia emissions by 40 percent per hen with no effects on egg production.

The project involved feeding 256 hens one of four types of diets which included corn distiller's dried grains with solubles (DDGS), wheat middlings and soybean hulls and a control. 

Research has shown that adding fermentable fiber to pig diets lowers ammonia emission and the project wanted to verify if the same would happen to laying hens, said Kristjan Bregendahl, assistant professor of poultry nutrition at Iowa State.

All three fibre diets resulted in lower ammonia emissions.

Since egg and ethanol are both critical industries in Iowa, reduction of ammonia emission by feeding corn DDGS would create a significant impact as it comes at no extra cost, Bregendahl said. Ammonia-lowering feed additives can add as much as US$8 to US$10 a tonne of feed, she added.

In fact, corn DDGS may even lower feed cost, because it supplies energy and nutrients to the diet, Bregendahl said,

Hens fed the fiber diets did not produce more manure, and egg production and egg mass were not affected.

However, feed consumption increased by 2 percent for hens fed the corn DDGS or soybean hulls diets. Researchers found it can be remedied by using more accurate energy values for corn DDGS and soybean hulls.

The results were announced at the ISU Poultry Science Day, the Iowa Egg Symposium and the Midwest Poultry Federation convention.