Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2007
Publication Date: 7/17/2007
Citation: Roberts, S.A., Xin, H., Kerr, B.J., Russell, J.R., Bregendahl, K. 2007. Effects of Dietary Fiber and Reduced Crude Protein on Nitrogen Balance and Egg Production in Laying Hens. Poultry Science. 86:1716-1725. Interpretive Summary: The excretion of nitrogen and volatilization of ammonia are major concerns for the poultry industry, impacting both environmental quality and animal productivity. Inclusion of feed ingredients with high concentrations of fiber and feeding diets low in crude protein have been shown to lower ammonia emission in other livestock species, but has not been well documented in laying hens. This research demonstrated that feeding moderate levels of dietary fiber to laying hens will not affect egg production or nitrogen excretion, and that while a 1% lower dietary crude protein may reduce egg mass, it will dramatically reduce the amount of nitrogen excreted. This information is important for scientists at universities, feed companies, and laying hen-egg production facilities showing that diets can be modified to maintain laying hen productivity, but dramatically reduce ammonia emissions.
Technical Abstract: Ammonia (NH3) emission is a major concern for the poultry industry and can be lowered by dietary inclusion of fibrous ingredients and by lowering the dietary crude protein (CP) content. The objectives of this research were to determine the effects of dietary fiber and low-CP diets on egg production and nitrogen (N) balance in laying hens. A total of 256 Hy-Line W-36 hens were fed diets with two contents of CP (normal and low) and four fiber treatments in a 2 x 4 factorial arrangement from 23 to 58 wk of age. The fiber treatments included a corn and soybean meal-based control diet and diets formulated with either 10.0% corn distiller's dried grains with solubles (DDGS), 7.3% wheat middlings (WM), or 4.8% soybean hulls (SH) added to contribute equal amounts of neutral-detergent fiber. The CP contents of the low-CP diets were approximately one percentage unit lower than that of the normal-CP diets. All diets were formulated on a digestible amino acid basis and were isoenergetic. There were no effects (P > 0.05) of including corn DDGS, WM, or SH in the diet on egg production, egg weight, egg mass, yolk color, feed utilization, or BW gain. Each of the fiber diets resulted in an increase (P ' 0.05) in N consumption, yet N excretion was not affected (P > 0.05). The low-CP diets did not affect egg weight, feed consumption, or BW gain (P > 0.05), but egg production, egg mass, feed utilization, N consumption, and N excretion were lower than from the hens fed the normal-CP diets (P < 0.05). The results of this study show that dietary inclusion of 10% corn DDGS, 7% WM, or 5% SH, but not 1% lower dietary CP, does not affect egg production or N excretion.