Life-cycle assessment of animal feed ingredients: Poultry fat, poultry by-product meal and hydrolyzed feather meal

This study presents an environmental life cycle assessment of poultry fat (PF), poultry by-product meal (PBM) and steam hydrolyzed feather meal (HF). These ingredients are obtained by rendering poultry byproducts and can be used as valuable feedstuffs for the fish feed industry, displacing traditional fishmeal and fish oil, promoting a circular economy system by reducing waste, adding value to by-products of the poultry production and reintroducing them in the economy as high-value products. A life cycle inventory and model were implemented for the PF, PBM and HF production chains based on data collected from two poultry by-product rendering units: the first producing both PF and PBM, and the second producing only HF. Four environmental impact categories were assessed using the CML life-cycle impact assessment method: global warming (GW), abiotic depletion (AD), acidification (AC) and eutrophication (EUT). The impacts calculated with economic allocation for 1 t of PF, 1 t of PBM and 1 t of HF from poultry byproducts are 666, 726 and 597 kg CO2 eq (GW); 3.8, 4.2 and 3.2 kg Sb eq (AD); 4.2, 4.6 and 4.7 kg SO2 eq (AC); and 1.8, 2.0 and 2.1 kg PO(4)(3-)eq (EUT), respectively. The rendering process of by-products is mainly responsible for GW and AD (mainly due to process heat), while the poultry production is the main contributor for AC and EUT. In more detail, a sensitivity analysis of alternative multifunctionality procedures for dealing with poultry by-products was performed, showing that the selected allocation method has a huge influence on the life cycle impacts, with higher impacts when mass allocation is employed instead of economic allocation. Additionally, a sensitivity analysis was conducted on the type of energy used in the rendering process, and distances in poultry by-product transportation to the rendering plants. The results show that the fuel source for process heat or the electricity generation system has a significant influence on the impacts, while the transportation distance has much less. (C) 2019 Elsevier Ltd. All rights reserved.