Protein Quality Assessment in Soya Feed Products

Protein quality in soya feed depends on balancing deactivation of anti-nutritional factors like trypsin inhibitors with preservation of digestible amino acids. Heat treatment methods—toasting, steaming, extrusion—must be optimized to avoid nutrient damage. Key quality indicators include trypsin inhibitor activity (TIA), protein dispersibility index (PDI), and urease activity, measurable in feed labs. TIA above 4 mg/g in soya cake correlates with poor feed conversion. Near-infrared spectroscopy (NIRS) enables rapid assessment of amino acid availability. Monitoring these parameters ensures consistent feed quality for swine and poultry. Target ranges for TIA and PDI are defined in Table 1. This guide, part of the OK-Net EcoFeed initiative, supports sustainable feed production in Europe and is produced by Wageningen University & Research, Netherlands, under the EU Horizon 2020 programme. Published 2023, it supports feed producers, animal keepers, and advisors in optimizing soya-based rations.