Strenuous starch

Janne Karin Brodin

The starch in barley occurs in the form of tiny balls, or granules, inside the grain. They are so tightly packed that the starch is difficult to get at for the enzymes whose job it is to break them down in the animal’s stomach and bowel.

Anita Stevnebø

This means that the nutritional value of barley is less than other types of grain. PhD student Anita Stevnebø has been searching for barley strains with more easily accessible starch.

Barley is a tricky feed ingredient in concentrates for monogastric animals like chickens as well as for ruminants. Due to the climatic conditions, barley is widely cultivated in Norway. Norwegian barley is used solely for animal feed, and time shows that the feed industry does not utilize enough compared to the total production.

Maize is a better grain ingredient for concentrates than barley is. However, since barley is the grain we can grow in Norway, we need to find out whether we can increase the percentage of Norwegian barley in concentrates by cultivating strains that are better suited for such use – strains that may compete successfully with maize.

New barley strains
In this PhD project, Norwegian as well as foreign barley strains with certain starch attributes/qualities were analyzed and tested in feeding experiments with chickens and cows. The foreign strains have a different granule size and starch composition than the Norwegian ones. The question was whether the starch in some strains was more easily digestible than the starch in the normal Norwegian strains that are used today, and whether it would be advisable to start growing new strains in Norway.

Starch structure of little importance
The results showed that even though there was some variation in the degradation – the breaking down – of starch among the strains when experiments were carried out in laboratory test tubes, the differences were of little to no practical importance in the practical feeding experiments. Genetic starch variations among strains are therefore of no practical importance.

As far as starch goes, any strain of barley may be used in the concentrates, and there is no gain in importing strains with a different composition starch.

Barley Photo: Janne Brodin

Improving other qualities in barley
This doctoral work has provided increased knowledge on the properties of starch in general and in particular in barley. It is now important to go on looking, and concentrate on improving other aspects of barley, such as fibre content.

Anita Stevnebø is 33 years old and comes from Bergen, Norway. She is employed as feed adviser at TINE (Norway's Dairy Cooperative). She took her Cand. Agric degree at IHA in 2001.

The trail lecture and public defence took place December 18 2009 at IHA.

Title of the thesis: Barley varieties (Hordeum vulgare L.) with different proportions of amylose – Effect on starch degradation characteristics and performance of monogastrics and ruminants

Prescribed subject of the trail lecture: Energy utilization in cattle, pigs and poultry - Efficiency in converting feed energy into meat

Professor Birger Svihus has been her main supervisor. Professor Odd Magne Harstad has been assistant supervisor.

Updated: 18.01.10
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