PARTNER FEATURE ▶▶▶
Nitrogen excre- tion to the envi- ronment is known to be re- duced by 10% for each point of dietary protein reduction.
amino acids was needed to ensure optimal supply. Conse- quently, soybean meal was partially replaced by wheat and feed-grade AA. Performance was similar in the two treatments while the number of broilers affected by foot pad dermatitis dropped by 69% at d26 and by 51% at d40, showing a continuous ef- fect of the nutritional strategy after the experimental period (Figure 2). Foot pad dermatitis is a multifactorial issue, the re- sult of two main factors: the litter humidity and the ammo- nia content of the diet. Interestingly, reducing protein is also influencing many dietary factors such as potassium content which in turn reduces water intake, oligosaccharides which influence faecal viscosity, and lower ammonia content in litter, an irritant molecule to the skin.
Improved environmental performance Nitrogen excretion to the environment is known to be re- duced by 10% for each point of dietary protein reduction due
Figure 2 - Foot pad dermatitis severity in broilers fed standard and low dietary protein content (Sacranie et al., 2017). 100
80 80
70 60 50 40 30 20 10 0
24%
12% 2%
15% 24% 24% 8% 11%
to reduced catabolism of excess amino acids. As birds drink less, litter is also usually lighter, meaning less litter to export from the farm and drier, leading to reduced volatilisation of nitrogen into ammonia, a positive outcome for; bird and worker welfare and quality of air and water. Studies per- formed by Dr Méda from INRA showed a reduction of 20% to 30% of ammonia emissions per point of protein reduction. A comprehensive integration of those impacts is possible thanks to the life-cycle assessment approach, measuring all the inputs and outputs of a specific broiler farm system. Dr Méda also quantified the influence of dietary protein on the broiler footprint and showed significant improvement of en- vironmental performance of broilers fed low protein diets. When reducing nitrogen intake of the birds by 15%, climate change, eutrophication and acidification impacts are lowered by 8%, 7% and 5%, respectively.
86% 61% 52% 81%
Standard Protein
d26 Low Protein Moderate 14
Standard Protein
Slight ▶POULTRY WORLD | No. 2, 2020 No d40 Low Protein
Continuous improvement Further reduction of soybean meal and dietary protein is going to be a challenge, including the dietary energy supply: is our current energy system robust enough for the diets of tomor- row? The characterisation of alternative feedstuffs, the modu- lation of fibre fractions and functions and their impacts on per- formance, health and welfare will also need to be further investigated. Another aspect to consider lies in the fact that amino acids are not only building blocks of muscle proteins, they also present functionalities related to intestinal integrity & immunity, metabolism & cell signalling or meat quality. Argi- nine for instance is the direct precursor of nitric oxide. Nitric oxide is a cytotoxic compound induced in case of a health chal- lenge, while it can also contribute to vasodilatation, a key parameter to control the development of breast muscle myo- pathies. In conclusion, applying an agile amino acid deci- sion-making process adapted to specific situations allows to efficiently implement low protein broiler diet strategies.
References available on request
Number of birds, %
PHOTO: ZANAP VAN ZYL
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