| Anguilla Anguilla is an important kind of breeding animal of Chinese aquaculture. As the eel breed aquatics is becoming large scal and intensive, the breeding environment is getting worse and the eel diseases emerged with the use of a large amout of feed and the fish pharmaceutical.So how to improve the eel aquaculture water quality is an urgent problem to solve.Phytoplankton is the important component of aquaculture, The community composition is closely related to the aquaculture quality. Therefore, to explore the role the beneficial algae played in the control of the ecological conditions of aquaculture water body is significant to realize the goal of healthy breed aquatics.Now the ecological regulation and control of the algae has been studied, but the research on the eel aquaculture water body had been rarely reported yet. In this study, the algae composition of the eel pool was investigated to isolate and cultivate the dominant algae. The physiology and ecologic needs of the dominant algae and the effect to the physiological activity and quality of the eel were studied to provide the theory basic on the regulation and control of eel aquaculture water body treated with algae. At the same time, the beneficial algae was domesticated on purpose to explore the feasibility of the regulation of eel aquaculture water body used by the algae. The results will help to provide experimental basic on the ecological breeding of eel. The main research contents and results were as follows:1、The algae composition of the eel pool was investigated, one blue-green algae and one green algae of the dominant algae were isolated to be the experimental material. It was identified that the two kinds of algae were Microcystis sp. and Chlorella sp. by morphology observation.2、The growth and physiological activity of the eel treated with the two kinds of dominant algae were explored through the detection of related enzyme activity. The results shows:the Microcystis sp.and Chlorella sp. had no significant influence to the growth of the eel. The two kinds of algae can improve the amylase、protease and superoxide dismutase activity of the eel. It demonstrated that the two kinds of algae can improve the digest capability and stress resistance of the eel. The catalase activity of experimental group treated with Chlorella sp. had decreased5.32%compared with the control group while treated with Microcystis sp. had increased9.09%compared with the control group. The effect of the catalase activity was not obvious. Chlorella sp. inhibited acid phosphatase and alkaline phosphatase activity of the eel and Microcystis sp. promote the activity. It showed that Microcystis sp. would improve the activity of immune system.3、The toxicity of the isolated Microcystis sp. was determined by HPLC. It showed that the Microcystis sp. was poisonous, the poison content is MC-RR:5.491mg/g, MC-LR:1.915mg/g。4、The physiological response of isolated Chlorella sp. that conducted with microcystin was studied through the analysis of the growth and antioxidase activity of the eel. The results showed:the microcystin which concentration is under100μg/L had no significant influence to the growth of Chlorella sp. while the higher concentration of microcystin(1000ug/L) enhanced the growth of the Chlorella sp. for16.7%. The microcystin of concentration under100μg/L had no significant influence to the antioxidase activity of Chlorella sp. while the higher concentration of microcystin(1000ug/L) increased the SOD and CAT activity of the Chlorella sp. for24.50%'58.36%.5, The differences between the two kinds of algae absorbing the nitrogen and phosphorus were studied through the comparison of the nitrogen and phosphorus adsorption dynamics. The results showed:the isolated Microcystis sp. was suitable for high nitrogen and low phosphorus nutrition environment. Its optimum growth concentrations of N, P was:50mg/L-250mg/L for N and0mg/L-0.5mg/L for P; the isolated Chlorella sp. was suitable for low nitrogen and high phosphorus nutrition environment. Its appropriate concentration range of N, P was:25mg/L-50mg/L for N and75mg/L-125mg/L for P.6、Based on the study aboved, the isolated Chlorella sp. was cultivated outdoor for a small scale. The Chlorella sp. was applied in the aquaculture water body to analyse the water quality index, such as the nitrogen and phosphorus content in the water body, the transparency and the dissolved oxygen. The results showed:the Chlorella sp. increased the Chlorophyll and dissolved oxygen content in the water and decreased the water transparency. The strainaway rate of ammonia nitrogen、nitrite、nitrate and phosphate of the water were45.2%、58.8%、35.1%and47.5%, respectively. It demonstrated that Chlorella sp. played an important role in purifying the aquaculture water body. |
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