title: Effects of dietary protease on nitrogen emissions from broiler production: a holistic comparison using Life Cycle Assessment.
abstract: 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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors: School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
authors: Ilkka
authors: I
authors: Leinonen
authors: School of Energy, Environment and Agri-Food, Cranfield University, Bedford MK43 0AL, UK.
authors: Adrian G
authors: AG
authors: Williams
mesh_terms: D000383:Agriculture / Q000379:methods*; D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D002245:Carbon Dioxide; D002645:Chickens / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D019587:Dietary Supplements; D004063:Digestion; D004777:Environment; D005068:Eutrophication; D057232:Global Warming; D017752:Greenhouse Effect; D006801:Humans; D008372:Manure; D008460:Meat; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000494:pharmacology*; D030262:Soybean Proteins; D013025:Glycine max
chemical_list: D004044:Dietary Proteins; D008372:Manure; D030262:Soybean Proteins; D002245:Carbon Dioxide; D000641:Ammonia; D010447:Peptide Hydrolases; D009584:Nitrogen
keywords: Acidification Potential; Global Warming Potential; Life Cycle Assessment; ammonia emissions; broiler production; protease