Methionine, the raw material used in poultry feeds is in short supply, and is causing problems for feed manufacturers, and in turn for poultry farmers across the globe.
But what is methionine?
Methionine is an important amino acid in poultry nutrition, and is one of 22 amino acids, which form the building blocks of protein. Different proteins are composed of a blend of different proportions of amino acids. Livestock need protein for their growth and maintenance, but more specifically need differing blends of amino acids to support the various stages of their development. Some amino acids can be synthesised by the animal, and by conversion from other amino acids, but some cannot be produced by the animal, these are referred to as essential or limiting amino acids.
For poultry (and pigs) there are 10 essential amino acids which must be present in the diet in adequate quantity and in the correct proportions. If the first limiting amino acid is not adequately available to the bird, the surplus of the other amino acids is excreted. This is often explained by viewing protein as a barrel, with each of the staves of the barrel depicting essential amino acids. The analogy is completed by showing that as the water fills the barrel, the water flows out over the shortest stave. In the case of this diagram, methionine is the first limiting amino acid, and those in surplus above the water line, e.g. lysine is excreted.
Many amino acids are available in varying quantities as part of the normal raw materials used in feeds. Some amino acids can be purchased as `pure’ ingredients, and are added to the feed to balance the diet. Pure (or almost pure) sources of amino acids have been manufactured for Lysine, Methionine and Threonine for some time. More recently, other amino acids have come onto the market, but these are currently too expensive to be economically included in feeds.
`Pure’, or as they are also called; `synthetic’ amino acids are used in conventional feeds to ensure the optimum amino acid profile for the bird. Synthetic amino acids are not allowed to be incorporated in organic diets, so these diets have to rely on the amino acids naturally available in the raw materials. The first and second limiting amino acids in conventional and organic diets are methionine and lysine, and to a lesser extent threonine, as other essential amino acids are available in adequate quantities in the other main raw materials in the diet. In organic diets, lysine is usually adequately available (from soya) but methionine is not sufficiently available to achieve the feed specification. The only way to achieve the minimum methionine level is to add more methionine rich raw materials, such as sunflower. The outcome is that the lysine and protein are higher in organic diets when compared to conventional diets. As a result the birds are being over-supplied protein and certain amino acids, just to achieve the minimum methionine levels, so the bird has to excrete the surplus. This is not simple, as the bird has to remove the surplus amino acids in the liver before excretion, which is an energy demanding process known as deamination and is energy inefficient.
Methionine is essential for the young bird, as it helps with feathering, but in the adult bird in lay, methionine is essential for egg production, as a deficiency has a significant impact on egg mass (weight X numbers).
Conventional feeds have relied upon the availability of synthetic methionine to top up and balance poultry diets for decades, and until now its availability has been unlimited. Historically the price varied according to the price of other raw materials, the cost of the ingredients of methionine (some of which is a by-product of the petrochemical industry), and its relative availability. Synthetic methionine has been available in two forms; DL and in liquid. There are a few international manufacturers of the two forms of methionine and until recently they have had adequate stocks to satisfy world-wide demand. Over the last few years the demand for poultry meat has accelerated as Asia’s increased affluence has encouraged more meat in their diet. This has put pressure on the soya market and seen resulting increases in prices, but it has also put pressure on the supply of other feed ingredients, in this case methionine.
In the last few months, world stocks of methionine have dropped from over 100 days of supply to less than 50 days. One of the key suppliers of a vital ingredient to two of the larger methionine manufacturers had a production problem in the autumn, which added to the supply issues. . The global availability of methionine dried up, other manufacturers could not increase production, so that over a period of 8 weeks up to the end of the year, the price rose from less than £3 per kg to over £12 per kg – if a compounder could buy any!
Some compounders around the world will not have received sufficient methionine to meet their needs, and will be trying to balance their diets to overcome the shortfall, this is expensive to the diet, and not easy to do, as anyone who has tried to balance organic diets will confirm! Other than the surprising rise in feed costs from the lift in wheat and soya in the last three months, the price of feed will also be driven up by the escalating price of methionine.
At the moment one methionine plant is `down’ for regular maintenance, which is adding to the problem, but will be back on-line soon, and anew plant is currently being commissioned in Asia. Within a few years, demand will again challenge supply, and another shortfall will occur, and maybe we will not be so lucky. Maybe then we will run out of methionine to include in animal feeds. That will really challenge nutritionists, feed manufacturers and farmers.
In the short term, methionine prices should be returning to normal by the end of the first quarter of 2015.
