The study of feeds with delayed disintegration on the water quality and survival rate of fishes
| Autor: | Yen-tien Lu, 呂炎田 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 Aquaculture is very important to the economy of our country. When fish feeds are fed to the fishes, it is very common that many feeds are wasted before they are eaten by the fishes. The wasted feeds are not only a waste to the cost but also pollution to the water quality. The relationships among the wasted feeds, water quality and fish survival rate have not been well studied. This study first screened the polymers. The polymer solution was coated on the feeds and floatability and disintegration rate of the feeds were monitored. 1 % chitosan and 1 % ethyl cellulose solution were chosen for the coating of the feeds in the study. The effect of coating on the dissolved oxygen, biochemical oxygen demand, total suspended solids, ammonium form nitrogen, pH values, turbidity, and survival rate of the fishes was also monitored. General speaking, the results of this study show that the coated feeds reduced the turbidity, total suspended solids, and increased dissolved oxygen. Chitosan was not found to be toxic to the Dimidiochromis fuscotaeniatus. It seems that 1 % chitosan coating prolongs the life span of Dimidiochromis fuscotaeniatus and Copadichromis trimaculatus, on the contrary, 1 % ethyl cellulose coating appears not to be effective. In conclusion, more kinds and numbers of fish should be conducted in the future experiment in order to obtain more meaningful statistic results. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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