Cultivation of the duckweed, Spirodela, on cesspool slurry for fish feed | |
| Author | Chao, Chia-hsing |
| Call Number | AIT Thesis no. AE-83-19 |
| Subject(s) | Weeds as feed Fishes--Feeding and feeds |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | The specific objectives of the thesis were to investigate the optimum conditions for the cultivation of the duckweed, Spirodela polyrhiza, on pilot scale cesspool sludge loaded earth ponds, by measuring their growth rate and crude protein content, so as to optimize growth condition, and to provide a high quality protein feed for fish. Investigations were also made to determine the optimum feeding level of fresh duckweed for the tilapia, Oreochromis niloticus in concrete tanks. Loading cesspool sludge once a week with an amount of 2 m into each duckweed ponds would provide a constant nutrient supply. The maximum extrapolated yield of Spirodela polyrhiza grown on cesspool sludge was found to be 24.41 tons dry weight/ha/year, and the doubling time was 5.42 days (Expt. 3). The maximum crude protein content of Spirodela polyrhiza in the experiments was 38.41% but the average crude protein content of duckweed was 25.13% in Expt. 3. The optimum feeding level of duckweed (calculated on a 10% moisture content basis) for tilapia, Oreochromis niloticus was found to be 5% total body weight of fish per tank per day. The survival rate of the fish fed on 5% duckweed was found to be 100% in the experiment (12 weeks) with a yield of 388.59 per tank. It was observed that wind and temperature had noticeable effects on the growth of duckweed. Wind breaks and shading devices may need to be constructed to maintain a continuous mat of plants on the surface of the pond. Insecticide, Carbaryl, could be used to prevent insect growth. The rainy season was also found to be more suitable for duckweed growth than the dry season. |
| Year | 1983 |
| Type | Thesis |
| School | School of Environment, Resources, and Development |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Edwards, Peter |
| Examination Committee(s) | Eppendorfer, W.H. ; Wee, Kok Leong |
| Scholarship Donor(s) | Taiwan Cement Corporation, Taiwan, Rep . of China |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1983 |