Dietary fibre in the diet of the growing pig: effects on apparent digestibility and resultant implications for its use in reducing the incidence of oesophagogastric parakeratosis.

The effects on apparent digestibility of increasing dietary fibre concentrations in barley-based diets by substituting for barley either bran, oatmeal by-product, guar gum or pectin were studied using 72 pigs. Increasing substitutions of bran up to a maximum of 300 g kg-1 gave progressive decreases in apparent digestibility of dry matter, ether extract and gross energy fractions and in digestible and metabolisable energy contents, progressive increases in apparent digestibility of modified acid detergent fibre but had no consistent effect on either nitrogen or extract free of nitrogen fractions. Increasing substitution of oatmeal by-product up to the same maximum gave significant linear decreases in apparent digestibility of dry matter, extract free of nitrogen and gross energy, significant depressions in apparent digestibility of modified acid detergent fibre and significant increases in ether extract. Guar gum and pectin, both substituted to a maximum of 50 g kg-1 had no significant effects on apparent digestibility. The results are discussed in the context of the concentrations of dietary fibre needed to reduce the incidence of oesophagogastric parakeratosis.