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

Abstract

1. The study used a 3 × 3 factorial design to evaluate the effects of 3 additives (none; vitamin C {250 mg/kg}; copper sulphate {250 mg/kg}) and 3 enzyme additions (none; Avizyme 1300 {Finnfeeds Ltd, 1 g/kg in food}; Avizyme 1310 {liquid spray, post-pelleting, 0.5 g/kg}). All experimental diets were mixed, heat-conditioned (80°C for 2 min) and pelleted. Copper sulphate (diets 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 liquid 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 liveweight 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 =0.002), ileal apparent digestibility of starch ( P <0.001) and faecal apparent digestibility of starch ( P =0.003) and crude fat ( P <0.001) due to a negative additive × enzyme interaction when copper sulphate and dry enzyme were included together. 4. Vitamin C decreased in vivo viscosity by 20% but failed to have any effect on performance. Both enzyme forms gave similar improvements in performance in the absence of copper sulphate.