Study: Reducing nitrogen emissions through dietary adjustments

Due to increased scrutiny from government regulators and the public on air emissions from poultry production facilities, there is a growing incentive for producers to take cost-effective steps to enhance the emission profiles of their operations. To this end, a recent USDA-funded study conducted at Michigan State University has shown that by making simple changes to the diets fed to turkey toms, producers can reduce nitrogen emissions from their grow-out farms without sacrificing meat yields.

Researchers from Michigan State University, University of Maryland, and Purdue University detailed their findings in a recent issue of Poultry Science (“Effect of Amino Acid Formulation and Supplementation on Nutrient Mass Balance in Turkeys”; Poult. Sci. 2011 90: 1153-1161). The journal is published by the Poultry Science Association (PSA).

The authors studied the effect of diets containing different concentrations of crude protein and different amino acid (AA) supplementations on nutrient retention and excretion by turkeys. They observed that decreasing dietary crude protein from 110% to 100% of the amount recommended by the National Research Council (NRC), and adding Threonine to an AA supplementation of Lysine and Methionine, measurably reduced the nitrogen and cumulative ammonia (NH3) losses from turkey facilities with no differences in tom growth or feed conversion.

Specifically, the study showed that diets containing the three supplemental amino acids resulted in lower nitrogen excretion (by 12%) and a lower cumulative loss of ammonia (by 23%) when compared with diets containing only two supplemental amino acids. The Environmental Protection Agency monitors emissions of air pollutants, such as particulate matter, ammonia, hydrogen sulfide (H2S), and volatile organic compounds (VOCs), under the US Clean Air Act of 1990 (CAA). In 2005 the EPA announced an air quality compliance agreement to address emissions from certain animal feeding operations or AFOs.

Dr. Zefei Liu, Research Associate at Michigan State University and one of the authors of the study, noted: “The goals of the 2005 EPA agreement include ensuring compliance with applicable CERCLA [Clean Air Act, Comprehensive Environmental Response, Compensation and Liability Act] and EPCRA [Environmental Planning and Community Right-to-Know Act] provisions. Because some of these provisions carry hefty penalties for non-compliance, it is important for the poultry industry to continue to search for methods to monitor and control nutrient losses and air emissions from their operations. We hope that the findings of our study will contribute to this effort.”

Details on the study’s design, chemical analyses and air emission measurement methodologies, along with a more complete discussion of the findings, can be found in the original Poultry Science article.

Source: Poultry Science Association (PSA)