1. The effect of dietary probiotic supplementation on the growth, nitrogen utilisation and serum cholesterol content of broiler chickens was studied in 2 trials. 2. In experiment 1, the birds receiving the 0, 75, 100, 125 mg probiotic/kg diets had weight gains of 1204.0, 1272.0, 1268.3 and 1210.5 g, respectively at the end of 8 weeks of feeding. The group of birds fed on the 75 mg probiotic supplemented diet retained significantly (P<0.01) more nitrogen than the control birds. Serum cholesterol content was lower in the probiotic-supplemented birds (93.3 mg /100 ml) compared to the control birds (132.2 mg/100 ml). 3. In the second experiment the probiotic plus antibiotic-supplemented group of birds had the maximum weight gain (1148.5 g) followed by antibiotic (1141.3 g), probiotic-supplemented (1128.4 g) and control birds (1045.6 g) after 6 weeks. Nitrogen retention was greatest in the antibiotic-(48.5%) followed by the probiotic-(46.5%), probiotic plus antibiotic-supplemented groups (46.3%) compared to 40.2% in control birds. 4. The apparent metabolisable energy was greatest in birds receiving the probiotic plus antibiotic-supplemented diet (12.37 MJ/kg) followed by antibiotic-(12.00 MJ/kg), probiotic-supplemented birds (11.92 MJ/kg) than in control birds (11.62 MJ/kg). Serum cholesterol was significantly (P<0.01) lower in probiotic-supplemented birds (86.1 mg /dl) compared to 118.4 mg/dl in control birds.
