Oligosaccharides in canola meal and their effect on nonstarch polysaccharide digestibility and true metabolizable energy in poultry.

Balance studies utilizing laying hens and adult cockerels were conducted to determine the influence of oligosaccharides (raffinose and stachyose) present in canola meal (CM) on the digestibility of nonstarch polysaccharides (NSP) and on the TMEn of the meal. Ethanol extraction was used to produce oligosaccharide-free meal, and exogenous dietary enzymes (alpha-galactosidase and invertase) were employed to bring about oligosaccharide hydrolysis in the intestinal tract of the birds. In each of two balance trials, six hens individually housed were randomly allotted to each of the experimental diets in completely randomized design. Experiment 1 consisted of a factorial arrangement of treatments (two sources of proteins with or without enzyme supplementation), whereas Experiment 2 consisted of five diets: semipurified CM control, semipurified ethanol-extracted CM; semipurified ethanol-extracted CM plus raffinose; conventional CM; and conventional ethanol-extracted CM. Elimination of oligosaccharides by the use of exogenous dietary enzymes had no effect on NSP digestion. Removal of oligosaccharides by ethanol extraction increased NSP digestibility from 4 to 8%. A more pronounced effect (17% NSP digestion) was noted in hens fed a wheat-based diet containing 30% oligosaccharide-free CM. This latter effect may have been due to the relatively high content of water-soluble polysaccharides contributed by the wheat portion of the diet. The TMEn content of ethanol-extracted CM was 2,302 kcal/kg as compared with 2,426 kcal/kg for untreated CM. The data indicate no advantage of oligosaccharide removal with regard to the nutritive worth of canola meal.