Could fungi transform straw for ruminants? - News & Features
7 September 2017
Straw is the most common crop aftermath, but what to do with it if you're not making bales of it as rustic seating for middle class garden parties? Wheat straw especially, shouldn’t be used as feed for ruminants without supplementation, because it rarely provides enough energy and protein to meet an animal's requirements. However, straw is a good alternative in rations for cows and sheep if properly supplemented with higher quality feedstuffs.
In recent years, baling and selling wheat straw has become a more common practice. While uses for wheat straw are varied, the increased demand is driven by livestock farms using it as part of their feed rations.
Chew on this
Differences in feeding value vary between the straws. Oats is the most palatable and nutritious; barley straw is second and wheat straw has the lowest nutritional value of the main grains. Millet straw is more palatable and higher in energy and protein. Flax straw is lower in feed value than all the others because of its lower digestibility.
The degradability of straw is crucial when it’s used for animal feed, biological means of bioenergy production such as bioethanol production and when it is incorporated in soil.
No love for lignin
Wheat straw has only 51% digestible organic matter, due to encrustation with lignin that hinders the degradation of cellulose and hemicellulose by the rumen microbes. Complete or partial removal of lignin in the wheat straw is a therefore the key to realize its potential as a ruminant feed.
White-rot fungi break down the lignin in wood, leaving the lighter-coloured cellulose behind; some of them break down both lignin and cellulose. As white-rot fungi are able to produce enzymes, such as laccase, needed to break down lignin and other complex organic molecules, they've been investigated for use in mycoremediation applications.
Cud fungi be the answer?
One of the roles that fungi have played early on in mycoremediation studies is that some fungi do an excellent job in supporting and energizing other organisms into remediation activity, just as they often seem to support and energize those same organisms into living healthily in native ecosystems. Biological methods, including the use of fungi, have many advantages over chemical and physical methods
The Animal Nutrition Group at Wageningen University have been researching the use of two strains of Ceriporiopsis subvermispora on improving the nutritive value of wheat straw for ruminants and their research has been recently published in the Journal for Applied Microbiology.