碩士 / 國立嘉義大學 / 水生生物科學系研究所 / 106 / The study investigated the effects of culture processes and sun-dried on qualities of water and sediment of white shrimp (Litopenaeus vannamei). Furthermore, this study defines indexes of aging and evaluates the effects of sun-dry on qualities of water and sediment, and also the growth of shrimp. The experiment implemented two culture periods and sun-dry of sediment between the periods. Each culture period was 63 days, and the time for sediment drying was 14 days.The stocking density of shrimp was 20 individual each tank (about 103 individual/m2) in shrimp tank. No shrimp was cultured in the control. The initial length of shrimp was 2.5±0.5 cm, and daily feeding ratio was 5% of shrimp weight. The salinity of water was 5‰, and no water exchange in the experiment except a supplement of water loss by evaporation.
The total length of shrimp increased from 2.6 cm to 8.2 cm and weight increased from 0.4 to 1.8 g in average in the first culture period. The growth rate of shrimp at day 28-42 significantly slower than the rate at day 0-28. The levels of NH4+-N, NO2--N, and NO3--N in water were significantly higher than the control at day 7, 14, and 42, respectively, but their levels in sediment were higher than the control at day 28, 35, and 28. It reveals that accumulation of nitrogenous ions were significantly faster in the water than in the sediments. The contents of organic matter, organic carbon and total nitrogen in the sediments of shrimp tanks increased with culture time. The levels of organic matter and total nitrogen were significantly higher than the control after day 21, and the organic carbon was after day 14. The oxidation-reduction potential (ORP) of shrimp tank sediments decreased to highly reduced conditions (<-100 mV) after day 28. The productions of CH4 were first detected at day 35 in the shrimp tank sediment while not detected in the control during the culture period. Both productions of N2O and CH4 in the shrimp tank sediments were significantly higher than the control after day 35.
The contents of organic matter, organic carbon and total nitrogen in sediment decreased 0.96%, 0.35%, and 0.29%, respectively, during the sundry.
During the second culture period, the growth of shrimp significantly slowed down from day 35 to day 49. The levels of NH4+-N, NO2--N, and NO3--N were significantly higher in the water of shrimp tank than in the control at day 28, 56, and 14, respectively, but their levels in shrimp tank sediment were higher than the control at day 49, 49, and 56. The contents of organic matter, organic carbon and total nitrogen in the sediment of shrimp tank were significantly higher than the control after day 63, 14, and 7. The ORP in shrimp tank sediments decreased to highly reduced conditions after day 14. Both productions of N2O and CH4 in the shrimp tank sediment were significantly higher than the control after day 28. The production of CH4 were first detected at day 28 and 42 in the sediments of shrimp tank and the control , respectively.
The comparison of two culture periods indicates that the nitrogenous ions in water and sediment, the organic matter, the organic carbon, and the total nitrogen were lower in the second culture period than in the first culture period. The time was shorter in the second than the first culture for the appearance of highly reduced condition of sediment. Furthermore, both first detections of N2O and CH4 in the second culture were also shorter than first culture.
The results indicated that 18.76%、14.98% of input nitrogen were used by shrimp; 78.70%、82.47% accumulated in sediment, and 2.26%、2.44% transformed to N2O for the first and the second culture, repectively. In conclusion, the input nitrogen for shrimp culture mainly accumulated in sediment, then ingested by the shrimp, and fewer were transformed to gases by the microorganisms.
Finally, the results indicated that levels of water ammonia; sediment ORP, organic content, organic carbon, total nitrogen, ammonia, and production of N2O and CH4 are highly correlated to the sediment aging and are recommended to be carefully monitoring items in shrimp culture.
| Identifer | oai:union.ndltd.org:TW/106NCYU5061004 |
| Date | January 2018 |
| Creators | Chih-Hen Tseng, 曾致涵 |
| Contributors | Hong-Thih Lai, 賴弘智 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 145 |
Page generated in 0.0021 seconds