INFLUENCE OF DIETARY ENZYME COMPLEX ON THE PERFORMANCE OF BROILERS FED ON DIETS WITH AND WITHOUT ANTIBIOTIC SUPPLEMENTATION

1. The aim of the experiment was to test the possible interactions of an enzyme complex and a food antibiotic on the growth and metabolism, carcase yield, whole body composition and nutrient deposition in broil ers. The basal diet contained 400 g/kg barley. The four treatments wer e as follows: O-without supplements (control), E-enzyme complex Roxazy me((R)) G, 200 mg/kg, A-antibiotic avoparcin, 10 mg/kg, EA-Roxazyme G, 200 mg/kg plus avoparcin, 10 mg/kg. 2. Roxazyme C positively influenc ed weight gain, food conversion efficiency, energy metabolisability, f at and nitrogen utilisation and the dry matter content of droppings. F at and energy deposition in the whole body were also increased, wherea s protein deposition and carcase yield were not influenced. 3. Avoparc in increased energy metabolisability and fat utilisation, but had no i nfluence on nitrogen utilisation. No significant improvements from avo parcin were seen in growth or in nutrient deposition in the body. The fibre degradability (NDF and ADF fraction) was significantly depressed by antibiotic supplementation. 4. The inclusion of both supplements t o the diet did not have a fully additive effect on growth, energy meta bolisability, or fat and nitrogen utilisation. The interaction between enzyme and antibiotic for food conversion efficiency during the first experimental period (7 to 21 d) was nearly significant (P=0.053). Exc ept for fibre degradability (P less than or equal to 0.01), no other s ignificant interactions between enzyme and antibiotic were found.