Effects of raw and modi®ed canola lecithins compared to canola oil, canola seed and soy lecithin on ruminal fermentation measured with rumen simulation technique

The effects of four different canola lecithins applied at proportions of 30 g fatty acid kgÿ1 diet were compared with diets containing either no additional lipid or the same amount of fatty acids from canola seed, pure canola oil and deoiled soy lecithin, respectively. Four types of canola lecithin with increasing dispersibility in water were used: raw; deoiled; deoiled/hydrolysed; and hydrolysed/acetylated lecithin. The complete rations consisted of maize silage, hay and concentrate, and were simultaneously applied in 10 days lasting experimental periods in rumen simulation technique (Rusitec) with eight consecutive replications each. Like canola seed and pure canola oil, the lecithins also increased rumen ̄uid pH and propionate proportion of volatile fatty acids (VFA) whereas total VFA concentration and butyrate proportion were reduced. The level of effect of the canola lecithins on VFA concentration as well as on bacteria and ciliate count depended on the type of lecithin. A decrease in ammonia concentration was found with canola oil and all lecithins but not with canola seed. Compared with the unsupplemented diet, canola oil decreased both acetate to propionate ratio and methane release. The effects against methane were lower with canola lecithins, particularly when deoiled. The use of the lecithins did not affect ®bre degradation, whereas apparent protein degradation was signi®cantly lower than in the other treatments. In spite of its much higher linoleic acid content, deoiled soy lecithin had quite similar effects as deoiled canola lecithin. Overall, canola lecithins, particularly in a modi®ed form, could be advantageous in comparison with pure oils in ruminant nutrition in terms of nutrient degradation. # 2000 Elsevier Science B.V. All rights reserved.