The effects of adding xylanase, vitamin C and copper sulphate to wheat-based diets on broiler performance

1. The study used a 3 x 3 factorial design to evaluate the effects of 3 add itives ( none; vitamin C {250 mg/kg}; copper sulphate {250 mg/kg}) and 3 en zyme additions (none; Avizyme 1300 {Finnfeeds Ltd, 1 g/kg in food}; Avizyme 1310 {liquid spray, post-pelleting, 0.5 g/kg}). All experimental diets wer e mixed, heat-conditioned (80"C for 2 min) and pelleted. Copper sulphate (d iets NCu; DCu; LCu) and Avizyme 1300 (diets DN; DC; DCu) were added during mixing. Vitamin C was sprayed at 10 ml per kg (diets NC; DC; LC) and the li quid enzyme was diluted 20-fold and sprayed at the same rate (diets LN; LC; LCu), post-pelleting. 2. Additive or enzyme addition did not significantly affect DM intake or li veweight gain (LWG). Enzyme addition improved gain: food (P=0.014), AME:GE (P<0.001), ileal apparent digestibility of DM (P=0.008) and starch (P<0.001 ), faecal apparent digestibility of starch, crude fat and NDF (P=0.008; <0. 001; <0.001 respectively) and reduced in vivo viscosity (P< 0.001). 3. Copper sulphate addition depressed gain: food (P=0.047), AME: GE (P=0.00 2), ileal apparent digestibility of starch (P<0.001) and faecal apparent di gestibility of starch (P=0.003) and crude fat (P<0.001) due to a negative a dditive x enzyme interaction when copper sulphate and dry enzyme were inclu ded together. 4. Vitamin C decreased in vivo viscosity by 20% but failed to have any effe ct on performance. Both enzyme forms gave similar improvements in performan ce in the absence of copper sulphate.