Fiber in Animal Nutrition

51 4.1 Context – importance of dietary fiber in the rabbit nutrition As an herbivorous and monogastric animal, the rabbit is adapted for a high fiber intake, and in traditional breeding systems, the rab- bit is fed with forages, herbs and cereals. In more intensive breeding systems, the rabbit is usually fed with diets containing at least 45 to 60% of dietary fiber when measured with the TDF procedure (table 24).The rabbit could also be fed with high-energy/low fiber pelleted feeds, to improve its feed conversion. But, using too concentrated feeds increases the risks for digestive troubles (diarrhoea, growth troubles), particularly after weaning (Gidenne et al., 2010). Thus it is essential to understand, how dietary fibers act in rabbit nutrition, and how to optimise the fiber sup- ply in rabbit feeding to preserve the health, without a too large impairment of the growth. Therefore in this chapter, we will first recall very briefly the structure of the main fiber classes, followed by a short description of analytical methods routinely used for dietary fibers analysis in rabbit feeding (Chapter 4.2). Then we will present examples of classical fiber sources for rabbit feeding (Chapter 4.3), since the adjustment of specific fiber classes in rabbit feed is essential to reduce the risk of digestive trouble. As for other monogastric animals, the importance of fibers is due to effects on intake, rate of passage and mucosa functionality (Montagne et al., 2003). In the rabbit, their role as substrate for caecal microbiota and the effect on digestion will also be summarised in chapter 4.4. The rela- Fiber in Rabbit Nutrition Thierry Gidenne Table 24: Fiber level and other main constituents in pelleted feed for the rabbit Chemical criteria (g/kg as fed) Mean range Total dietary fiber (TDF) 450–600 Neutral detergent fiber (aNDFom) 280–460 Acid detergent fiber (ADFom) 150–230 Acid detergent lignin (ADL) 35–65 Crude fiber 120–180 Soluble fiber* 35–120 Other constituents Starch 80–130 Sugars 30–60 Crude protein (CP) 140–190 Ether extract (EE) 20–40 * Calculated as: OM-CP-EE-aNDFom-Starch-Sugars © ERLING Verlag