LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 6C: POULTRY AND PORK PRODUCTION SYSTEMS 8 th Int. Conference on LCA in the
Parallel session 6c: Poultry and Pork Production Systems
540
Agri-Food Sector, 1-4 Oct 2012
Assessment of digestibility improving enzymes potential to reduce
greenhouse gas emissions in broiler production
Anja Marie Bundgaard 1,* , Randi Dalgaard 2 , Mikkel Thrane 3 , Trakarn Prapaspongsa 1,4
1 Aalborg University, Department of development and planning, Vestre Havnepromenade 9, 9000 Aalborg, Denmark
2 2.-0 LCA consultants, Skibbrogade 5,1, 9000 Aalborg, Denmark
3 Dupont Nutrition and Health, Danisco, Edwin Rahrs Vej 38, DK-8220 Brabrand, Denmark.
4 Mahidol University, Department of civil and environmental engineering, 25/25 Puttamonthon, Nakorn Pathom, 73170, Thailand
Corresponding author. E-mail: anjamarieb@gmail.com
ABSTRACT
The objective of this study was to examine the potential of digestibility improving enzymes to reduce greenhouse gas (GHG) emissions
in broiler production. The product examined was a new enzyme called Axtra XAP, developed by DuPont, Danisco Animal
Nutrition. Two scenarios were compared: one where Axtra XAP was not included in the diet and one where Axtra XAP was included
in the diet. Axtra XAP facilitated higher inclusion rates of cheaper (and possibly more environmentally friendly) feed ingredients that
have a lower nutritional value in the diet. Axtra XAP’s environmental improvement potential was documented through a Life Cycle
Assessment (LCA) by applying a consequential approach including indirect land use changes (ILUC). The findings showed that
Axtra XAP could reduce GHG emissions from broiler production by 5%. A sensitivity analysis was conducted to assess the robustness
of the results and it showed that the result varied substantially. The most important parameters were the inclusion or exclusion of
ILUC and changes in the feed formulation.
Keywords: broilers, enzymes, consequential LCA, livestock feed, greenhouse gas emissions
1. Introduction
Food production represents around 1/3 of all human induced greenhouse gas (GHG) emissions (Foley et
al., 2011) and together with the continuous growth in population and affluence level, this represents a major
challenge for the earth’s ecosystems. The production of animal products for human consumption amounts to
18% of the total anthropogenic GHG emissions (FAO, 2006). No single solution exists which can address all
environmental problems caused by the livestock sector, but the use of digestibility improving enzymes in
animal feed has the potential to be an important solution. When enzymes are used in animal feed, they help
break down parts of the diet which the animal itself cannot break down in its digestive system. Therefore
nutrients from the diet are released which previously were unavailable to the animal. In addition enzymes
can help to remove the anti-nutrient effect of certain components in the diet. The enzymes can provide an
improved growth performance for a specific diet, or allow for a higher ratio of cheaper feed ingredients with
a lower nutritional value, while achieving the same growth performance (Barletta, 2011). Previous studies
have documented the considerable environmental advantages of applying enzymes, such as phytase and
other digestibility improving enzymes, in animal feed (Nielsen and Wenzel, 2007; Nielsen at al., 2008). The
objective of the present study was to examine the possible environmental improvement potential of digestibility
improving enzymes used in complex broiler diets. The study examined a specific enzyme product,
Axtra XAP, developed by DuPont, Danisco Animal Nutrition. The paper accounts for the main results of the
study.
2. Methods
The two feed formulations used in this study were formulated using a computer software tool that ensures
the lowest feed cost while still providing the necessary nutrition for the animal. They are economically optimised
according to US feed prices in 2011. Methane and nitrous oxide emissions caused by the broiler’s
manure and the manures end-use as an organic fertiliser are calculated according to IPCC (2006a; 2006b).
Enteric fermentation from the broiler was omitted, as no standard exists for poultry in the guidelines and
because enteric fermentation from poultry is very limited. A consequential approach (Weidema, 2003) was
applied and indirect land use changes (ILUC) were included. The approach used to calculate the effect of
ILUC was developed by Schmidt et al., (2011). The main principle in the model is that the current use of
land reflects the current demand for land, and that changes in demand for land will result in changes in land
use. The life cycle assessment (LCA) was modelled using the program SimaPro and it basically follows the
ISO 14040 and 14044 standards.