Manipulation of Dietary Protein and Nonstarch Polysaccharide to Control Swine Manure Emissions
2005
Clark, O Grant | Moehn, Soenke | Edeogu, Ike | Price, Jason | Leonard, Jeremy
Odor and greenhouse gas (GHG) emissions from stored pig (Sus scrofa) manure were monitored for response to changes in the crude protein level (168 or 139 g kg⁻¹, as-fed basis) and nonstarch polysaccharide (NSP) content [i.e., control, or modified with beet pulp (Beta vulgaris L.), cornstarch, or xylanase] of diets fed to pigs in a production setting. Each diet was fed to one of eight pens of pigs according to a 2 × 4, full-factorial design, replicated over three time blocks with different groups of animals and random assignment of diets. Manure from each treatment was characterized and stored in a separate, ventilated, 200-L vessel. Repeated measurements of odor, carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) emissions from the vessels were taken every two weeks for eight weeks. Manure from high-protein diets had higher sulfur concentration and pH (P ≤ 0.05). High-NSP (beet pulp) diets resulted in lower manure nitrogen and ammonia concentrations and pH (P ≤ 0.05). Odor level and hedonic tone of exhaust air from the storage vessel headspaces were unaffected by the dietary treatments. Mean CO₂ and CH₄ emissions (1400 and 42 g d⁻¹ m⁻³ manure, respectively) increased with lower dietary protein (P ≤ 0.05). The addition of xylanase to high-protein diets caused a decrease in manure CO₂ emissions, but an increase when added to low-protein diets (P ≤ 0.05). Nitrous oxide emissions were negligible. Contrary to other studies, these results do not support the use of dietary protein reduction to reduce emissions from stored swine manure.
显示更多 [+] 显示较少 [-]