Polymers of the plant cell wall or “fiber”: Their analysis in animal feeding and their role in rabbit nutrition and health

Abstract

Dietary fiber concepts historically differ in animal feeding as compared to human nutrition and health. For the latter, this is a rather modern concept, mainly developed in the 1960s (Hipsley 1953) to deal with several pathologies (colorectal cancer, etc.), regularly revisited (Trowell 1978, De Vries 1999, Elleuch et al. 2011), and often restricted to the polysaccharides of the plant cell wall of the fruit and legumes. In contrast, animal nutritionists deal with other “less refined” fiber sources, often from whole plants (forages, by-products of seeds processing, etc.), and recover a larger range of chemical components, including other polymers, such as polyphenolic (lignins, tannins) or polylipidic compounds (cutins) and so on. Thus, two centuries ago, Heinrich Einhof developed the so-called Weende method (which in fact was setup at Möglin in 1806, Germany, and not at the Weende agronomy station) to isolate a “crude fiber” residue (Van Soest and Mc Queen 1973) to assess the nutritional value of ruminant feeds (forages and grasses). Over the years, many systems of analysis have been proposed for the replacement of crude fiber, but none have been successful in dislodging Weende procedure as the official method, and it is still used in animal feeding, for example, for quality checking of fiber sources.