Limiting the impact of animal husbandry on the environment

The intensification of production which, over recent decades, has led to the development of intensive husbandry – particularly for pig and poultry – as well as its concentration in major European areas of production, has gradually increased the phenomena of pollution, especially by nitrogen. Nitrogen and its by-products (nitrates, nitrites and ammonium hydroxide, etc) come from animal slurry which is spread over the fields. In some areas, this has led to amounts which exceed regulations in soil, water and the air. This is the reason why some countries – and, more recently, the European Union (Directive 96 / 61 / EC of September 24th, 1996) have implemented regulations which aim to limit and reduce nitrogen excesses in the environment.

 

The nitrogen contained in animal droppings comes predominantly from feeds. Nitrogen which is mainly ingested in the form of proteins is metabolized by animals in order to assimilate the amino acids which are necessary for their growth. In this process the proteins which are supplied above the animal’s amino acid requirement are catabolized and lead to an increase in nitrogen excretion.

 

 

 

The most effective way to reduce these excesses therefore involves limiting them at source or, in other words, in the feeds. In contrast to curative measures (exportation and processing of liquid manure, compost, improvement of infrastructures), the preventive measures take direct action against the source of the pollution. Thus, lowering the dietary protein level is an extremely effective strategy to reduce nitrogen waste by animals. Studies on the subject have shown that lowering protein content in feed for pig or poultry by one point makes it possible to reduce the amount of nitrogen excreted by animals by about 10%.

 

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Feeduse amino acids play a vital role in the elaboration of these dietary formulas with low protein content. In fact, whilst reducing content in the form of proteins, they make it possible to maintain the content of essential amino acids in such a way that the animal’s requirements are met and performances are maintained. The possibilities of lowering the content of feed proteins are therefore directly dependent on the availability of amino acids. Thus, with the amino acids which are now commercially available (L-Lysine, L-Threonine, DL-Methionine and L-Tryptophan) it is possible to reduce the amounts of nitrogen excreted into the environment by about 30%. With the availability of amino acids such as L-Iisoleucine and L-Valine in the future, it is possible to envisage reductions of nitrogen waste of up to 50%.

 

The development of feed formulas with increasingly low protein content and the generalization of their use will make it possible to develop a sector of animal production which is even more respectful of the environment.

 

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