Effect of dietary supplementation with Achyranthes aspera seed on larval rohu Labeo rohita challenged with Aeromonas hydrophila.

Larval rohu Labeo rohita were fed four different diets: three of the diets contained Achyranthes aspera (prickly chaff-flower) seeds at 0.10% (D1), 0.25% (D2), or 0.50% (D3); the fourth diet was a control diet (D4; no A. aspera supplementation). After 70 d, the rohu were injected intraperitoneally with live Aeromonas hydrophila. Mortality of fish was recorded for 7 d. In the D4 group, the first mortality was observed within 12 h of exposure, whereas in the D1-D3 treatment groups, mortality was first observed at 24 h postexposure. In the D4 group, 50% of fish died within 72 h of exposure, whereas in the D3 group, 10-15% mortality occurred between 72 and 84 h. The cumulative mortality rate was 50% for D4, 40% for D1, 35% for D2, and 15% for D3. Total tissue protein level in the larvae was higher for the D2 and D3 groups than for the other groups. Glutamic oxaloacetic transaminase, glutamate pyruvate transaminase, and thiobarbituric acid reactive substance levels were significantly lower in D3 larvae than in the other groups, whereas lysozyme and nitric oxide synthase levels were significantly higher in D3 larvae compared with the other groups. Dietary supplementation with A. aspera seeds at the 0.50% level provided protection against oxidative stress, prevented tissue damage, and enhanced disease resistance in rohu larvae.