Determining the Nitrogen Budget and Ammonia Emissions from Commercial Broilers Grown in Environmental Chambers

Authors: MITRAN, L - UNIV MD, PRINCESS ANNE; HARTER-DENNIS, J - UNIV MD, PRINCESS ANNE; Meisinger, John

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2007
Publication Date: 2/15/2008
Citation: Mitran, L., Harter-Dennis, J.M., Meisinger, J.J. 2008. Determining the Nitrogen Budget and Ammonia Emissions from Commercial Broilers Grown in Environmental Chambers. Journal of Applied Poultry Research. 17:34-46.

Interpretive Summary: Understanding the fate of added nitrogen and ammonia losses from commercial broilers is important for improving flock nitrogen efficiency and for reducing the detrimental effects of ammonia, which include decreased flock productivity and degradation of environmental quality. A nitrogen budget for commercial broilers was constructed by measuring nitrogen inputs in feed and chicks, outputs in broilers and ammonia, and the increase in litter nitrogen for commercial broilers grown for 42 days. The broilers were raised in five environment chambers at the University of Maryland Eastern Shore, with each chamber housing 500 birds. Ammonia emissions were determined by continuous sampling of the exhaust air from each chamber and trapping ammonia in acid. The major nitrogen input was in the feed, this nitrogen was accounted for as 67% in the broilers, 26% accumulated in the litter, and 13% in ammonia-nitrogen emissions. This nitrogen budget showed an average difference between the inputs and measured outputs of only 5%, which indicates a successful nitrogen balance. Ammonia emissions were modest during the first three weeks, but increased over the remaining four weeks when 77% of the total ammonia loss occurred, due to the greater nitrogen excretions and a rise in litter pH and moisture during the last four weeks. Daily ammonia emissions over the 42 day grow-out averaged 0.37 grams of ammonia-nitrogen per bird. Total ammonia-nitrogen emissions averaged about 15 grams per bird, which is consistent with other literature values and the high nitrogen recovery in the broilers. These results are significant to poultry managers and environmental advisors, because they show that management practices leading to high broiler N recovery are consistent with lower ammonia emissions.

Technical Abstract: Understanding the fate of added nitrogen (N) and ammonia emissions from commercial broilers is important for increasing flock N efficiency and reducing ammonia problems such as decreased flock productivity, reduced air quality, N deposition to neighboring ecosystems, and the loss of plant-available litter N. Nitrogen inputs in feed and chicks, outputs in broilers and ammonia, and the change in litter N were determined for 500-bird flocks of commercial broilers grown for 42 days in five 37m2 environmental chambers at the University of Maryland Eastern Shore. Ammonia emissions were determined by continuous sampling of exhaust air from each chamber and trapping the ammonia in phosphoric acid. The major N input was in the feed, which was accounted for as 67% ± 2% in the broilers, 26% ± 2% accumulated in the litter, and 13% ± 0.4% in ammonia-N (NH3-N) emissions. The average difference between the measured N inputs and outputs was 5% ± 3%, indicating a successful N balance. Ammonia emissions were modest the first three weeks, but increased over the remaining 4 weeks when 77% of the total NH3-N loss occurred, most likely due to greater N excretions and a rise in litter pH and moisture. Daily NH3-N ranged from 0.13 to 0.78g NH3-N per bird, with a 0-42 day mean of 0.37g NH3-N per bird. Total NH3-N emissions over 42 days averaged 15.3 ± 0.5 g NH3-N per bird, which is consistent with other literature values and the high N recovery in the broilers. These results support the view that management practices leading to high broiler N recovery are consistent with lower ammonia emissions.