Fiber in Animal Nutrition

Dietary Fiber and Analytics 12 dividually by chromatography or as a total by a colorimetric assay (Englyst et al., 2007). A value is obtained for total dietary fiber and, if required, for soluble and insoluble dietary fiber. A small modification allows cellulose to be measured separately. The de- tailed GC-analysis gives an indication of the content of cellulose, pectin, b -glucan and other polysaccharides. Such information allows more accurate prediction of the phy- siological role of NSP from different feeds. Mc Cleary et al. (2012) extended the me- thod with respect to the codex alimentarius definition of fiber in food. They combined the enzymatic gravimetric method with a liquid chromatography for determination of soluble oligosaccharides. The method was validated through an AOAC/AACC colla- borative study. Similar as in human nutrition a diffe- rentiation in an insoluble and soluble fraction of total dietary fiber was discussed for pet food because also in pets, chronic diseases like obesity, diabetes and other metabolic disorders have increased (De Godoy et al., 2014). While the insoluble fraction may be related to intestinal regulation the soluble fiber is associated for example to glucose absorption and lipid metabolism. A comprehensive comparison between the NSP Method from Englyst and the AOAC Method (Prosky) was published by Englyst et al. (2007). Wolters et al. (1992) compared in their study different methods for the determination of dietary fiber. Table 1 shows some results for the detergent-analysis (van Soest), the AOAC (Prosky et al.) and the NSP Method Dietary fiber method Whole-wheat mean Toasted soy bran NDF ADF 10.8 ± 0.2 2.9 ± 0.2 44.1 ± 0.5 31.5 ± 0.2 AOAC-total AOAC-insoluble AOAC-soluble 12.0 ± 0.4 10.1 ± 0.6 1.1 ± 0.4 53.9 ± 2.3 49.0 ± 0.8 6.4 ± 0.5 Englyst-total Englyst-insoluble Englyst-soluble 8.9 ± 0.1 7.2 ±0.1 3.3 ± 0.1 44.8 ± 0.2 38.2 ± 0.5 7.6 ± 0.2 Table 1: Dietary fiber content in two products determined by four different methods (mean and standard deviation) in g/100 g dry matter (Wolters et al., 1992) Figure 1: Possible method of classifying “dietary fiber” (Lunn and Buttriss, 2007) Insoluble components Soluble components Non-digestible carbohydrate “Traditional insoluble fibers” Resistant starch “Traditional soluble fibers” Oligosaccharides © ERLING Verlag