EFFECTS OF ENZYME SUPPLEMENTATION ON THE NUTRITIVE-VALUE OF DEHULLED LUPINS

1. Separate balance experiments were conducted to assess the potential of 2 commercial enzyme supplements to improve the nutritive value of dehulled lupin kernels. One supplement (enzyme A) contained primarily xylanase, pentosanase, hemicellulase activities and the other (enzyme B) primarily beta-glucanase, hemicellulase and pectinase activities. 2 . The enzymes were added at 0, 0.25, 0.50, 0.75 and 1.00 g/kg in diets containing (g/kg) lupins 300, sorghum 543, casein 91, celite (as mark er) 20, and vitamins and minerals 46. Control diets, with and without enzyme supplementation contained sorghum and casein at 800 and 134 g/k g, respectively, and no lupins.3. Growth rates and food conversion rat ios (FCR) of birds over 7 days were not affected by lupin inclusion or enzyme supplementation. FCR of broilers fed on the sorghum diet was i mproved by enzyme A but not by enzyme B. 4. Ileal starch digestibiliti es were slightly lower in birds fed on the lupin control diet (no enzy me) compared to the basal control diet. 5. Enzyme A increased the AME of the lupins from 10.01 MJ/kg DM to 11.65 MJ/kg DM when added at 0.5 g/kg. Higher rates of supplementation did not lead to further increase s in AME values. 6. Enzyme A did not improve starch digestion in the d iets but insoluble non-starch polysaccharides concentration in the dig esta decreased (50.41-42.71 g/g acid insoluble ash marker) with increa sing enzyme supplementation, suggesting that the improvement in AME wa s the result of increased fermentation of fibre in the hindgut. 7. Enz yme B did not affect the AME of lupins nor the ileal digestibility of nutrients, but caused an increase in the concentrations of soluble non -starch polysaccharides in the ileal digesta of chickens (19.21-35.77 mg/ml). This was accompanied by an increase in ileal digesta viscosity (11.4-34.2 m.Pa/s).