Effect of Amino Acid Formulation and Supplementation on Air Emissions from Tom Turkeys

Abstract

Air emissions were determined for turkeys fed four diets in a 22 factorial design to determine the effects of diets with 100% or 110% of NRC-recommended amino acid (AA) formulation when the diets contained either two (lysine and methionine) or three (lysine, methionine, and threonine) supplemental AA. Hybrid tom turkeys were raised and monitored in 12 rooms (3 reps per diet; 20 toms per room at hatch, culled to 16 toms per room at 21 days, and then 12 toms per room at 28 days of age). Air emissions were measured throughout the 140-day study. Data were analyzed statistically using the Mixed model procedure of SAS. The 100% NRC diets contained less N compared to the 110% NRC diets. Diets containing three supplemental AA had less N content compared to diets containing two supplemental AA. Cumulative feed intake (55.7 kg bird-1) and bird weight (BW; 19.8 kg bird-1) were not affected by diet. Feeding the 100% NRC diets resulted in 9% less cumulative N intakes and 12% less cumulative NH3 emissions as compared with feeding the 110% NRC diets. Formulation with three supplemental AA did not affect N intake but resulted in 25% less cumulative NH3 emissions, as compared with formulation with two supplemental AA, because it significantly reduced the NH3 emission rate (ER) on a per kg N consumption basis (88 vs. 109 g d-1 kg-1 N consumed) . The toms fed the 100% NRC diets generated lower ER of NH3 (1.5 vs. 1.8 g d-1 bird-1), H2S (3.4 vs. 4.4 mg d-1 bird-1), and non-methane total hydrocarbons (NMTHC; 0.08 vs. 0.10 g d-1 bird-1) than the 110% NRC diets (p < 0.05). Results of stepwise regression analysis confirmed the positive influence of N/S intake, room air RH, ventilation rate, and room air temperature on ER of NH3 and H2S. The study demonstrated the potential of reducing NH3 and H2S emissions from turkeys through diet modification of AA while maintaining acceptable production performance. No diet effect was observed on greenhouse gas emissions (N2O and CH4).