Evaluation of the inhibitory effects of four different microecological preparations on Cladophora

Cladophora blooms could cause an imbalance in the structure and function of aquaculture pond ecosystems, which may seriously restrict the development of the Eriocheir sinensis aquaculture industry. The microecological preparation is environmentally friendly which was used aquaculture farming recently. In this study, a 144-h acute exposure test was arranged to evaluate the effect of microecological preparation to the growth performance, physiological responses, and antioxidant capacity of Cladophora. Four microecological preparation treatments, including EM bacteria, Bacillus subtilis, Bacillus licheniformis, nitrifying bacteria, and one control group, were used. The results showed four different microecological treatments inhibited algal growth and chlorophyll content at a concentration of 1 x 10(8) CFU L-1. Besides, lower fresh weight and chlorophyll content of Cladophora were found in the EM bacteria, B. subtilis, B. licheniformis, and nitrifying bacteria treatments than that of the control group significantly. Moreover, the content of antioxidant enzyme activities including superoxide dismutase, peroxidase, and catalase activities, and malondialdehyde concentration of Cladophora increased in all treatment groups. Furthermore, the growth performance and antioxidant capacity data indicated that the EM bacteria treatment had the greatest inhibitory effect, followed by the B. subtilis treatment. In conclusion, the microecological preparation could inhibit the growth of Cladophora and EM bacteria were more effective.