A Natarajan’s scientific contributions

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, 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.

1. The effect of probiotic supplementation on egg production, on serum and yolk cholesterol and on egg shell thickness in 24 White Leghorn layers was studied from 28-38 weeks of age. 2. In 3 treatments the diet was supplemented with 0, 100 and 150 mg probiotic/kg food. 3. In the 100 mg probiotic group, egg production improved by 5%, and shell thickness improved slightly, with fewer thin-shelled eggs than in the control (8.6% compared to 18.6%). 4. The initial serum cholesterol concentration of 170.2 mg/dl in control birds remained similar throughout the 10-week experimental period, whereas in the 150 mg group the initial value of 176.5 mg/dl decreased to 114.3 mg by week 10. 5. Yolk cholesterol concentration was 14.69 mg in the control group and 11.28 and 11.37 mg/g in the 100 and 150 mg probiotic groups respectively. Overall mean total egg cholesterol was thus reduced by probiotic supplementation.