Fiber in Animal Nutrition

Fiber in Rabbit Nutrition 58 having an ADF level over 15% (see table 27). When a sufficient supply of lignocellulose (at least 18%) is provided, it is advisable to replace some starch or protein by digestible fibers fractions. The HRi is reduced and the feed efficiency is weakly modified (Gidenne, 2015). 4.5 Dietary fiber requirements to reduce the risk of digestive disorders after weaning We here proposed a summary of the fiber requirement for post-weaned and growing rabbits, to reduce the risk of digestive troubles after weaning, without a too large impairment of growth performances. One criterion is not sufficient to define the fiber requirements of complete balanced feed. Three key points must be controlled (table 27): 1- The level of ADF should be over 19%. 2- The quality of the lignocelluloses plays also a role in the digestive health, and the minimum level of lignins should be 5% in a feed. 3- The balance between the poorly digested “ADF” and high digested fibers “DF” fractions should be respected. The ratio DF/ADF should be under 1.3, to avoid an unbalanced intake of highly fermentable polysaccharides. Recent data about SF revealed contrasting results and at present it appears not consi- stent enough to deserve a supplementary requirement. Table 27: Fiber requirements to prevent digestive troubles for the growing rabbit Unit: Post weaning Endof fattening %, as fed basis (28–42d old) (42–70d old) Lignocellulose "ADFom" ≥19 ≥17 Lignins "ADL" ≥5.5 ≥5.0 DF/ADFom** ≤1.3 ≤1.3 ** Digestible fibers fractions = [hemicelluloses (NDF-ADF) + water-insoluble pectins] Figure 14: The risk of digestive trouble (HRi) in the growing rabbit is dependent of the ratio DF / ADF 70 60 50 40 30 20 10 0 0.75 1 1.25 1.5 1.75 Y = 3.67e 1.61X R 2 = 0.69 Ratio DF/ADF in the feeds lower HRi higher HRi Gidenne et al., 2004b Gidenne et al., 2004a Debray et al., 2002 Bennegadi et al., 2001 Gidenne et al., 2000 Health Risk index, aer weaning % © ERLING Verlag