Chemical analysis of cell wall and energy digestibility in growing pigs

Ileal and faecal fibre digestibility was studied in pigs, with six diets containing increasing levels (1.5-9%) of beet pulp, alfalfa and wheat bran. The apparent digestibility of fibre was assessed from the crude fibre (CF), the neutral and acid detergent fibre (NDF, ADF) and the non-starch polysaccharides (NSP). The analytical methods employed gave clearly different figures for fibre content in the diets and their respective ileal and faecal residues. Crude fibre, NDF and ADF underestimated fibre degradation in the hindgut by more than 100% when compared with NSP values. Xylose and glucose polymers were the most resistant to digestion. At the ileal level, the NDF overestimated fibre digestibility. Solubilization, particularly of uronic acid residues, anterior to the caecum was apparent. Solubilized NSP glucose, on the other hand, was substantially degraded in the small intestine