Levels Of Non-starch Polysaccharides Research Articles

Digestion of diets containing molassed or plain sugar-beet pulp by growing pigs

Large White × Landrace pigs were grown from 25 to 55 kg on diets containing 0, 150, 300 or 450 g kg −1 molassed (M) or plain (P) sugar-beet pulp (SBP) (coded C, 15 M, 30 M, 45 M, 15 P, 30 P, 45 P, respectively). The apparent digestibilities of dry matter (DM), nitrogen (N), non-starch polysaccharides (NSP) and neutral detergent fibre (NDF) of the diets were determined when pigs attained live weights of 27 and 50 kg. Diets contained similar amounts of DM, N and gross energy (GE). Levels of dietary NSP and NDF increased with SBP content. The major NSP residues in SBP were uronic acids, arabinose and glucose, in the approximate ratio of 1:1:1, whereas glucose accounted for 66% of the NDF NSP. In 27-kg pigs given Diet 45 P, digestibilities of DM and N were significantly reduced relative to the control. In contrast, digestibilities of the NDF and NSP fractions of most SBP diets were higher than those of Diet C. When pigs had attained 50 kg live weight, digestibilities of all components had increased, and there were no significant differences in the digestibility of DM between each of the seven diets. However, the abilities of 50-kg pigs to digest the N and NSP fractions of Diet C were higher and lower respectively, than those of similar pigs fed Diet 45 P. The arabinose and uronic-acid content of the diets were highly digestible as were the minor components mannose, galactose and non-cellulosic glucose. Xylose and glucose were poorly digested by 27-kg pigs, but their digestion by 50-kg pigs was substantially improved. Increasing inclusion levels of SBP resulted in concomitant increases in faecal bulk. These results indicate that young pigs fed diets containing up to 300 g kg −1 MSBP, can digest DM and N as well as, and NDF and NSP better than, pigs fed a conventional diet without SBP.

Cell-wall polysaccharides of rye-derived wheats: Investigations of the biochemical causes of dough stickiness

Rye contains much higher levels of cell-wall polysaccharides such as pentosans and (1 → 3),(1 → 4)- β-glucans than wheat, suggesting that these polysaccharides might contribute to the undesirable dough stickiness found in many rye-derived wheats such as those with the IB/IR chromosome translocation. The pentosan and β-glucan content of whole grain and endosperm samples was determined for two varieties of wheat, two of rye and three rye-derived wheats. The pentosan and β-glucan contents of normal and rye-derived wheat were similar. Slightly higher β-glucan levels were detected in the endosperm of the rye-derived wheat samples exhibiting dough stickiness so this character was examined further. Flour produced in a laboratory mill from 18 wheat samples, including 12 rye-derived wheat lines, contained 1·04–2·39% pentosan and 0·14–0·28% β-glucan but the content of these polysaccharides did not show a clear association with the level of dough stickiness. Examination of flour of three varieties of normal wheat grown at each of nine locations showed that there were significant differences in the pentosan and β-glucan content of different varieties of wheat and in the wheat from different sites. The non-starch polysaccharide levels in the flour from rye-derived wheats were within the range found in normal wheats.