The present study has been carried out the effect of leaf extract of Melia azedarach at different concentration, such as 1.0g, 1.5g and 2.0g formulated diet against 0.1 ml of CFU/ ml 10 5 cells Aeromonas hydrophila on catla catla. The physiological parameters, such as Survival and Mortality, Antibody response, Phagocytic activity, Oxygen consumption, opercular movement, and Growth rate were studied. Result revealed that control fish showed 60% mortality and 20%, mortality at 1.0g concentration of plant extract, 10% mortality at 1.5g concentration of plant extract 30% mortality at 2.0g concentration of plant extract was observed. The maximum level of physiological activity Survival and Mortality, Antibody response, Phagocytic activity, Oxygen consumption, opercular movement, and Growth rate was recorded at 1.5g of plant extract formulated diet treated fish. When compared with control, However physiological parameters was significantly (p<0.05) increased when compared with control. Materials and Methods Alive and activity fishes (12± 1g) were collected from High-tech fish farm, Madurai, Tamil Nadu, India. The fishes were maintained in non-chlorinated at 20 day. The ground nut oil cake, fish meal and rice bran, tapioca, soybean, were mixed and sterilized. And then add a multivitamin tablet. The above mixed foods were added with different concentrations (1.0g, 1.5g and 2.0g) of plant extract prepared using shoxlet apparatus. These extract Melia azedarach extract used for experimental fishes and without plant extract diet for control fish. The food was made into small pellets. 0.1 ml of 10 CFU/ ml of Aeromonas hydrophila was injected intraperitoneally both for control and experimental. In every seven days following physiological studies such as,(Table 1).
