Effects of dietary protease on nitrogen emissions from broiler production: a holistic comparison using Life Cycle Assessment

BACKGROUND: The aim of the study was to quantify the effects of the use of a protease Ronozyme® ProAct in broiler feed on the environmental impacts of broiler and broiler feed production chains. This was done by using a Life Cycle Assessment (LCA) modelling approach with data from trials using both standard soya-based broiler diets and reduced-protein diets with added protease.\n\nRESULTS: The results for the feed production chain showed that there was a reduction in all environmental impact categories when protease was used in the diets. The biggest reduction occurred in the category of Global Warming Potential, mainly as a result of decreased carbon dioxide emissions from land use changes related to soya production. In the results for the broiler production chain, there were relatively bigger reductions in Eutrophication Potential and especially in Acidification Potential, mainly as a result of reduced feed protein content and subsequent nitrogen emissions from housing and manure management.\n\nCONCLUSION: The use of protease in the broiler diets reduced the environmental impacts of both feed production and broiler production. The latter is mainly through reduced ammonia emissions, which has substantial benefit per se in the poultry industry. © 2015 Society of Chemical Industry.