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 conduct ed to determine the influence of oligosaccharides (raffinose and stach yose) present in canola meal (CM) on the digestibility of nonstarch po lysaccharides (NSP) and on the TME(n) of the meal. Ethanol extraction was used to produce oligosaccharide-free meal, and exogenous dietary e nzymes (alpha-galactosidase and invertase) were employed to bring abou t 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 d esign. Experiment 1 consisted of a factorial arrangement of treatments (two sources of protein with or without enzyme supplementation), wher eas Experiment 2 consisted of five diets: semipurified CM control, sem ipurified ethanol-extracted CM; semipurified ethanol-extracted CM plus raffinose; conventional CM; and conventional ethanol-extracted CM. El imination 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 pronounce d effect (17% NSP digestion) was noted in hens fed a wheat-based diet containing 30% oligosaccharide-free CM. This latter effect may have be en due to the relatively high content of water-soluble polysaccharides contributed by the wheat portion of the diet. The TME(n) content of e thanol-extracted CM was 2,302 kcal/kg as compared with 2,426 kcal/kg f or untreated CM. The data indicate no advantage of oligosaccharide rem oval with regard to the nutritive worth of canola meal.