Significant environmental gains can be achieved by changing how the energy value of feed ingredients is calculated. It sounds almost too good to be true, but in the long term, the new calculation method is expected to reduce the dependence on soybean meal in broiler feed. Instead, the use of locally produced protein-rich feedstuffs with a significantly lower climate footprint will increase.

The Problem with Soybean Meal

Feed accounts for approximately 70% of the total climate footprint in broiler production. In Denmark and the rest of the world, soybean meal is the primary source of protein and amino acids in feed for industrial broiler production. The problem, however, is that the climate footprint of soybean meal is seven times higher than that of locally grown alternatives like peas and rapeseed cake. With a new calculation method, it is expected that it will be possible to both reduce the protein content in broiler chicken feed and completely or partially replace soybean meal with locally produced protein crops. Both actions can significantly reduce the climate footprint of broiler production.

A New Energy Evaluation System

GUDP has just granted funding for a project to develop a new system for calculating the energy content of feed for broilers. Currently, the energy content is calculated as metabolizable energy (ME). The problem with the ME system is that it overestimates the energy value of protein-rich feed ingredients. In practice, this means more protein-rich feed ingredients are used in broiler feed than necessary to meet the animals' amino acid requirements. The project aims to develop a more precise system based on net energy (NE). This system will provide a more accurate assessment of the energy value of protein-rich feed ingredients and thus prevent this overestimation.

Protein is a Poor Energy Source

The ME system does not account for the lower energy value of amino acids compared to carbohydrates and fats, and the protein’s energy value depends on its amino acid composition. 'We know that excess amino acids, which are not used for growth and production, are used by the animals as an energy source,' explains Associate Professor Dr. Tofuko Woyengo, who leads the project. 'The costs of metabolism are simply higher because energy is lost as heat. This heat production is not accounted for in the current system,' he says. Additionally, the conversion of amino acids to energy increases nitrogen excretion into the environment. Put in simple terms, protein-rich feed ingredients should be used in the feed to meet the amino acid needs of broiler chickens, not their energy needs.

Learning from Pigs

Denmark has used the NE system successfully for feed evaluation for pigs since the early 2000s. This led to significant reductions in the protein content of feed mixtures, nitrogen excretion into the environment, and the feed costs for pig producers. In this project, the successful approach will be transferred to broiler chickens. The switch to the NE system for broiler chicken feed is expected to result in a 53% reduction in nitrogen excretion and a 3% reduction in feed costs.

A Familiar Face is Involved

To tailor an NE system to broiler chickens, the energy value of known feedstuffs must first be recalculated based on published knowledge about their components. This will be supplemented with new experiments to determine the energy value of new Danish protein-rich feed ingredients. The new equations based on old and new data will then be integrated into the commercial feed optimization software Agrosoft WinOpti. In connection with this, the project consortium has brought back a familiar face to the project, Dr. Carsten Pedersen. He is an expert in the field and was previously employed as a PhD student at Aarhus University (previously the Danish Institute of Agricultural Sciences). At that time, he was involved in developing the NE system for pigs. The new NE system for broilers will be validated under commercial large-scale production conditions in the project before it is widely implemented and used in practice. 'We expect to have a system ready for use when the project is completed in three years,' says Dr. Tofuko Woyengo.

Benefits for the Environment and Economy Locally and Globally

The project is a significant step towards sustainable poultry farming in Denmark. It is also a model that can easily be extended to the rest of the world. 'Initially, it will probably be Europe, where there is a strong focus on the environment and the use of local crops, that the interest will be greatest,' notes the project leader. The new system is expected to lead to a significant reduction in greenhouse gas emissions and nitrogen pollution, therefore it aligns perfectly with Danish and European climate goals and efforts to reduce the agricultural impact on the environment. To the benefit of broiler producers, it will also reduce feed costs and increase their productivity. Finally, a lower consumption of imported soybean meal and an increased use of local raw materials will promote sustainable agricultural production.