Optimization of a nitrogen fertilization regime in fertilized Nile tilapia (Oreochromis niloticus) ponds with supplemental feed | |
| Author | Luu Thi Thanh Truc |
| Call Number | AIT Thesis no.AQ-05-16 |
| Subject(s) | Nile tilapia--Feeding and feeds Nitrogen in animal nutrition |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AQ-05-16 |
| Abstract | An experiment was conducted in fifteen 200-m2 earthen ponds at the Asian Institute of Technology, Thailand during November 2004 to March 2005. The objectives of this study were to optimize nitrogen fertilization rates in Nile tilapia ponds with supplemental feed, to assess effects of different rates of nitrogen fertilization on tilapia production and water quality, to quantify nutrient budget, and to assess the cost and return of tilapia production in fed ponds fertilized at different nitrogen rates. Five nitrogen fertilization rates were used as treatments in triplicate: 0%, 25%, 50%, 75%, and 100% of 28 kg N ha lwk-'. Phosphorus fertilization rate was fixed at 7 kg P ha' wk-' for all the treatments throughout the experiment. Sex-reversed all-male Nile tilapia (97.4-103.2 g size) were stocked at 3 fish m-2, and fed at 50% satiation feeding rate in all ponds. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P>0.05). Water quality parameters were not significantly different among treatments, except chlorophyll a and nitrite-N. Chlorophyll a concentration increased with increasing N fertilization rate. Nutrient budget showed that the percentages of nitrogen incorporated into Nile tilapia from total nitrogen inputs were significantly higher in the treatments with lower nitrogen fertilization rates. The highest percentage (37.14%) was achieved in the treatment without nitrogen fertilization (0% N). The percentages of phosphorus incorporated into Nile tilapia from total phosphorus inputs ranged from 22.33% to 31.59% without significant difference among the treatments with different N fertilization rates. Economic analysis showed that the treatments with higher N fertilization rates (75% and 100% N) resulted in positive net returns, while the treatments with lower N fertilization rates (0%, 25% and 50% N) gave negative net returns. Treatment with 75% and 100% nitrogen fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AQ-05-16 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Yi, Yang; |
| Examination Committee(s) | Yakupitiyage, Amararatne;Thakur, Dhirendra Prasad;Fitzsimmons, Kevin; |
| Scholarship Donor(s) | Vietnamese Ministry of Education and Training; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2005 |