Life Cycle Impact Assessment of Soybean Meal Sourced from Argentina, Brazil, China, India, and the United States on Protein and Energy Basis in Swine Diets

Abstract The objective of this study was to compare soybean meal (SBM) sourced from different countries based on their nutritional and environmental footprint contribution to swine diets. The environmental footprint data for producing feed ingredients used in this study were based on the Global Feed LCA Institute. The life cycle impact assessment (LCIA) was performed using ReCiPe 2016 Midpoint (H) V1.09/World (2010)H in SimaPro LCA software (version 10.2, PRé, Netherlands) with the database from DATASMART 2023, ecoinvent, and US LCI inventories. The functional unit for LCIA outputs was defined as 1 kg of SBM or feed ingredient. The CP, AA, and ME values for SBM of different origins were referred from previously published data on SBM nutrient content and digestibility, NE values were calculated using NRC (2012) equation. Data are presented on an as-is basis to align with the functional unit used in the LCIA outputs for the feed ingredients. U.S. SBM’s CP level is greater CP than Argentina and China SBMs but lower than India and Brazil SBMs. The SBM from Brazil contained the smallest proportion of SID Lys:CP (6.18%), followed by India (6.31%), Argentina and China (6.32%), and greatest in the U.S. (6.49%). The ME of U.S. SBM is greater than India but lower than other countries. The SBM from Argentina contained the highest NE (kcal/kg) content (2,277), followed by Brazil (2,168), China (2,153), U.S. (1994), and India (1,994). The global warming potential (GWP, including land use change and Peat; kg CO2 equiv.) was the lowest in U.S. SBM (0.540), followed by India (1.705), China (2.75), Argentina (4.204), and Brazil (4.273). In LCIA parameters (LCIA per kg of CP, lysine, or SID lysine basis), US SBM showed lower GWP, freshwater eutrophication, terrestrial ecotoxicity, and land use than others, however water consumption was the highest amongst the countries. When LCIA parameters were estimated based on ME and NE of SBM, U.S. SBM showed the lowest impact on global warming, terrestrial ecotoxicity, and land use but the highest impact on water consumption despite having the second lowest ME and NE estimates. Given the differences in nutrient concentration and GWP of soybean meals, the resulting growing pig diets also had different calculated GWP. Soybean meal from the U.S. contributed the least (28.7%) proportion of GWP to the entire diet followed by India (53.3%), China (66.0%), Argentina (74.9%), and Brazil (75.1%). These observations refute the prevailing narrative that SBMs are the major ingredient with the greatest contribution to the environmental impact of swine diets and that substitution will decrease the impact of the diet. These findings also demonstrate that the environmental impact of growing pig diet is highly dependent on the origin of the ingredients and holistic evaluations require accurate data.