Crude Protein and Phosphorus Levels in Poultry Feed – a Key to High Resource Efficiency

Commercial poultry farming has grown considerably in recent years. This study aims to analyse its protein supply and identify potential for optimising phosphorus utilisation and feed efficiency.

The importance of commercial poultry farming is increasing in Switzerland, as evidenced by high growth rates in egg (+35%) and broiler (+42%) production over the past decade. With higher production, the number of birds is also increasing (currently about 15.3 million utility chickens, of which 3.59 million are laying hens and 9.68 million are broilers). In terms of environmental relevance, high protein efficiency and phosphorus (P) utilisation are crucial. Excessive nitrogen inputs from groundwater or air lead to eutrophication of sensitive ecosystems such as forests, oligotrophic grasslands and peatlands, and to eutrophication of lakes. Nitrogen enters ecosystems via nitrates in groundwater and by way of aerial deposition in the form of ammonia.

Optimising protein supply in poultry farming

The aim of this study is therefore to assess the current status of protein supply in poultry farming in cooperation with the industry and to identify opportunities for improvement. The survey covers more than 99% of the Swiss market share for broiler feed and around 90% of the feed for laying hens and pullets. In broiler production, the energy content (apparent metabolizable energy, AME) of conventional feed increases from the beginning to the end of the fattening phase (+0.40 MJ/kg), while crude protein (CP) (-25.5 g/kg) and lysine (-1.90 g/kg) decrease significantly. The feeds used contain an average of 13.01 MJ/kg AME poultry, 185.5 g/kg CP, 11.61 g/kg lysine and 4.82 g/kg P. Crude protein values for fattening are up to 11% below the recommendations issued by international breeding companies. The energy (11.67, 11.60, 11.50 MJ/kg AME), CP (177, 166, 159 g/kg) and P (4.85, 4.66, 4.50 g/kg) contents of the feed for laying hens decrease continuously over the course of the laying phase. The weighted averages in commercial feeds are 170.0 g/kg CP and 4.75 g/kg P at 11.67 MJ/kg AME poultry. The use of pure amino acids to balance the amino acid profile and of the enzyme phytase to improve phosphorus availability is not allowed in organic feed. Organic feeds therefore contain 22 g/kg more CP for laying hens and 33 g/kg more CP for broilers than conventional feeds. P contents are about 1 g/kg higher. The CP and P contents used provide a basis for reevaluating and adjusting the IMPEX^[1] values.

[1] IMPEX: Nutrient import/export balance sheet as part of the Suisse Bilanz, a Swiss agricultural planning and enforcement instrument and precondition for the receipt of direct farm payments.