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Fermentation and enzyme addition increase the digestibility of fibre and phosphorus

A combination of fermentation and enzyme addition increases the nutritional value of alternative sources of feedstuffs for pigs. Particularly the digestibility of fibre and phosphorus is improved.

[Translate to English:] Næringsværdien af alternative fodermidler til svin kan forbedres med en kombination af enzymtilsætning og fermentering. Det er især fordøjeligheden af fiber og fosfor, der forbedres. Foto: Janne Hansen

The fluctuating prices of traditional feed ingredients for pigs such as barley, wheat and soybean meal have made alternative, cheaper feed sources  interesting. However, some of these feed materials have a high fibre content, making them difficult for pigs to digest. The fibre in the feed can also reduce the digestibility of other nutrients, particularly protein.

Scientists from Aarhus University have found a possible solution to the problem. Fermentation and addition of enzymes are both on their own promising methods for improving the nutritional value of the fibre-rich liquid feed. In her PhD study at the Department of Animal Science, Aarhus University, Grethe Venås Jakobsen examined the effects of combining the two methods.

She found that digestibility was improved by combining fermentation with enzyme addition. This was true for several nutrients, but especially for phosphorus and fibre.

Enzyme addition and fermentation each have their advantages and are complementary processes. The main advantage of fermenting the feed material was that it improves the digestibility of phosphorus. The main advantage of enzyme addition was the reduction of fibre content in the feed and increased fibre digestibility.

The studies included feedstuffs such as high moisture maize, peas, rapeseed cake and dried distillers grain with solubles. For several of these materials the biggest challenge is the large amount of  non-starch polysaccharides  and lignin that have a low digestibility in pigs and may have a negative effect on the digestibility of protein and other nutrients.

Various enzymes and enzyme mixtures comprising combinations of ?-glucanase, xylanase, cellulase, pectinase and phytase were tested.

The final proof that the combination of enzymes and fermentation improves the nutritional value of the feed could be obtained by measuring their impact on growth performance and meat quality of pigs. The advantages of combining enzyme addition with fermentation should be balanced against the price of feed materials, enzymes and the equipment needed for the fermentation process.

The entire thesis "Improving nutritional value of pig diets containing local crops and co-products by fermentation and enzyme addition "can be accessed here.

Further information

Senior Scientist Nuria Canibe
Department of Animal Science
E-mail: nuria.canibe@anis.au.dk
Phone: +45  8715 8058