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Research r...WeanersTrial report 942

Trial report no. 942: Fermented rapeseed for weaners

Production value dropped by 7-9% in weaners (9-30 kg) fed fermented rapeseed compared with soybean meal and rapeseed cake. Trial results revealed poorer FCR and lower gain, and no effect on health.


The effect on productivity of fermented rapeseed cake from the manufacturer ‘Fermentationsexperts A/S’ was investigated in weaners in the weight interval 9-30 kg. Results revealed that production value dropped by 7% in weaners fed 15% fermented rapeseed cake compared with control (15% soybean meal) and by 9% compared with the pigs fed regular rapeseed cake. There was no significant difference in production value between the control pigs and the pigs fed regular rapeseed cake. The pigs fed fermented rapeseed cake had a lower gain and a poorer FCR. In practice, the feed containing fermented rapeseed must cost DKK 11 less per 100 FUgp for Danish pig producers to be able to cover the loss in productivity (ie € 1.3 less per 100 kg). 

The reduced productivity may be attributed to several factors:

  • Glucosinolate degradation products may have formed in the rapeseed used that adversely affected pig growth.
  • Crude protein digestibility was set to 85% in the fermented rapeseed cake, and this may have been too high whereby not enough free amino acids were added to the diet. Digestibility of rapeseed cake is normally 76% (9 percentage units lower). If the poorer performance is to be explained from crude protein digestibility alone, the digestibility of crude protein in fermented rapeseed cake must be set lower than 76%.
  • A combination of the above. 

Besides rapeseed cake, the fermented product used in this trial also contained potato peel, molasses and wheat bran. The purpose of fermenting rapeseed cake is to improve the digestibility of protein and energy and possibly reduce glucosinolate content. Analyses demonstrated that the glucosinolate content of the fermented rapeseed was in fact reduced, but it is unclear whether this is attributed to fermentation, enzymatic degradation caused by myrosinase or damage by heat during drying post-fermentation (additional heat-treatment). Glucosinolate degradation products will have formed if glucosinolates were transformed via heat-treatment or myrosinase, but it is unclear whether the fermentation process also caused glucosinolates to transform into anti-nutritional substances.

Updated: 18.06.2012


Hanne Maribo

Chief scientist, PhD

Tel.: +45 3339 4390