Impact of Crude Protein Levels and Source on Air and Odor Emissions from Swine Operations

摘要

This study was conducted to determine the impact of crude protein (CP) levels and source of CP in the diets has on the emissions of ammonia (NH_3), hydrogen sulfide (H_2S) and odorous volatile organic compounds from manure. Two sets of 24 pigs were fed six different diets ranging in CP levels of 8.7-17.6%; fiber levels 8.3-19.6%; sulfur levels 0.11-0.38%. The CP source material included the following: 1) corn alone supplemented with amino acids (AA) (extremely low CP); 2) corn-soybean meal supplemented with AA (low CP); 3) standard corn-soybean meal; 4) corn-corn gluten meal; 5) com-canola meal; and 6) corn-poultry meal. Pigs were fed and their waste collected twice daily over the 42 day feeding trial. Crude protein levels in the diet significantly increased levels of NH_3 and H_2S levels in manure as well as pH of the manure. Protein source impacted crusting and crusting of manure significantly reduced both NH_3 and H_2S emissions. Odorous VOCs concentrations were higher by CP levels, and source of CP did also significantly affect odorous VOC emissions. Indole compounds increased with CP content, but phenols and volatile fatty acids (VFA) were not significantly different. Emission of H2S was significantly higher in higher protein diets and accounted for between 60-90% of total odor.