Breeding Better Barley for Feed
DENMARK - Low-protein malt barley is fine for drinkers of ale while high-protein feed barley meets the needs of pigs and cows. However, now that environmental effects are also an important issue, a new kind of barley becomes necessary: one that has the right kind of protein content and amino acid composition.Scientists from the Faculty of Agricultural Science are therefore working on developing barley cultivars for animal feed that not only have a sufficient amount of protein, but the right kind of amino acid profile. Barley with a better protein quality grain could:
- save money for farmers (because they can decrease the amount of supplements in the feed)
- decrease the need for importing protein and
- help reduce the amount of unutilised nitrogen ending up in the environment.
Traditionally, feed barley has been bred for centuries to have a higher protein content in order to meet the protein requirements of farm animals. However, the breeding focused on higher protein quantity while the nutritional value was not addressed. High input agriculture preferentially increases the "wrong kind of storage proteins". Non-essential amino acids such as proline and glutamine are found in excess in these modern cultivars with a higher protein content. After having made their way through the animals’ digestive system, such non-essential amino acids, which are not utilised, end up as nitrogen contamination in the manure. The manure is typically spread on fields as fertilizer but too much of a good thing is not good and the excess nitrogen is leached from the soil, finding its way into the aquatic environment.
Finding the optimal solution
One way to solve the problem is to feed with low-protein barley, but that would require an additional protein supplement in the feed, such as imported soybean protein and essential amino acids, in particular lysine, threonine and methionine.
"We could save money on imported protein feedstuffs and be more protective of the environment if we could find barley cultivars with a high protein content but a lower content of proline and glutamine," says senior scientist Eva Vincze from the Faculty of Agricultural Sciences at Aarhus University.
The search for high-protein, low non-essential amino acid barley cultivars has already begun. From a collection that already numbers more than 300 different barley cultivars from all over the world, and using modern genetic technology, Eva Vincze and her colleagues hope to develop as near a complete picture as possible of all the relevant characteristics of high protein cultivars. They will cross-reference these to current malt barley lines to develop a knowledge-based selection of lines that could have enhanced protein qualities.
"We are already familiar with the gene expression profiles coding for storage proteins during grain development. We found that the different members of these protein 'families' are different in amino acid composition and expression at different times during grain development. We want to promote the right families (alleles with a better protein composition)," explains Eva Vincze. Once good cultivars are found, the next step will be to breed for the trait.
The project, which is financed by the Danish Ministry of Food, Agriculture and Fisheries’ Food Research Programme 2008, started in January 2009 and is being carried out in collaboration with Sejet Plant Breeding, Danish Pig Production and local farmers, who will perform feed trials with the potentially "good" cultivars.