Mitigation of ammonia emissions from pig production using reduced dietary crude protein with amino acid supplementation

To mitigate ammonia (NH₃) emissions from pig production and understand dynamic emission profiles, reduced dietary crude protein (CP) with amino acid supplementation was studied with 720 pigs in a 12-room research building for 155 days that covered from weaned to finishing stages. The pigs were divided into three 4-room groups and fed with 2.1–3.8% reduced CP (T₁), 4.4–7.8% reduced CP (T₂), and standard (control) diets, respectively. Compared with the control group, T₁ and T₂ decreased manure volumes and manure NH₄ ⁺-N concentrations. Group-mean NH₃ emission from the control group was 68.9 g d⁻¹ AU⁻¹ (AU = 500 kg live mass). Emissions from T₁ (46.7 g d⁻¹ AU⁻¹) and T₂ (29.8 g d⁻¹ AU⁻¹) were reduced by 33.0% and 57.2% (p < 0.05), respectively. Dynamic peak NH₃ emissions appeared during the third nursery phase for T₁ and T₂, but delayed to the first grower phase for the control group.