Effect of dietary levels of rapeseed meal and polyethylene glycol on the performance of male broiler chickens

In a 5 × 2 factorial experiment, the performance of male broiler chickens given starter (1 to 21 d) and finisher (21 to 42 d) diets containing five concentrations (0, 74.5, 149.0, 223.5 and 298.0 g/kg) of rapeseed meal (RSM) and two concentrations (0 and 15 g/kg) of polyethylene glycol (PEG) was measured. 2. Bodyweight gain and food intake decreased (P<0.01) with increasing dietary RSM both in the starter and finisher phases. 3. The relative weights of thyroid glands, liver, heart and the ratio of water to food intake increased (P<0.01) while the dressing percentage, abdominal fat‐pad weight and the feather condition score decreased (P<0.01) with increasing dietary RSM. 4. The mortality rate was increased (P<0.05) on diets containing 149 g/kg or more of RSM. The main causes of deaths and culling on the high RSM diets were enlarged livers and hearts, liver haemorrhage and leg disorders. 5. The inclusion of 15 g/kg PEG in the starter diets increased (P<0.01) bodyweight gains and food intake. It also increased (P<0.05) water consumption between 37–39 d, faecal moisture content at 40 d and the haemoglobin content in blood. 6. There were no interactions between the dietary concentrations of RSM and PEG on growth and other variables measured.