博士 / 國立臺灣海洋大學 / 水產養殖學系 / 92 / Kuruma shrimp Marsupenaeus japonicus Bate reared in salinities of 18 ‰, 26 ‰, 34 ‰ and 42 ‰ (g kg-1) were examined for (1) nitrogenous excretion including ammonia-N excretion, urea-N excretion and organic-N (organic nitrogen) excretion, (2) the levels of nucleotide-related compounds, ammonia, urea and uric acid in tissues, and (3) the activities of enzymes involved in uricogenesis like xanthine dehydrogenase (XDH) and xanthine oxidase (XOD), and activities of emzyme involved in urecogenesis like uricase and arginase. Excretions of organic-N and urea-N were significantly higher (p < 0.05) in salinity of 42 ‰ than in 18 ‰, whereas, ammonia-N excretion was significantly lower (p < 0.05) in 42 ‰ than in 18 ‰. Hemolymph ammonia, urea and uric acid levels, and epidermis ammonia, urea and uric acid levels were significantly higher (p < 0.05) in salinity of 42 ‰ than in 18 ‰, whereas hepatopancreas ammonia, uric acid and gill uric acid levels were significantly higher (p < 0.05) in 18 ‰. The levels of total nucleotide-related compounds including xanthine and hypoxanthine in the gill were significantly higher (p < 0.05) in salinity of 42 ‰ than in 18 ‰, whereas the levels of total nucleotide-related compounds including xanthine and hypoxanthine in the hepatopancreas were significantly higher (p < 0.05) in 18 ‰. Activities of arginase in the gill, midgut, hepatopancreas and muscle were significantly higher (p < 0.05) in salinity of 42 ‰ than in 18 ‰, and activities of XDH and XOD in the hapatopancreas were significantly higher (p < 0.05) in salinity of 42 ‰ than in 18 ‰.
M. japonicus displays activities of enzymes involved in uricogenesis like XDH and XOD, and activities of emzyme involved in urecogenesis like uricase and arginase. Uricogenesis occurs from the degradation of nucleotide. Activities of XDH and XOD in the hapatopancreas increased in 42 ‰, whereas no significant difference of uricase activity in the hepatopancreas was observed among four salinity levels. An increase of uricogenesis occurs for the shrimp in 42 ‰. Uric acid levels in hemolymph and epidermis increased significantly for the shrimp in 42 ‰. Uric acid produced in the hepatopancreas was transported and accumulated in the epidermis, and removed along with the epidermis at the time of molting. Formation of urea was considered due to uricolysis and hrdrolysis of arginine. The activity of uricase shows no increase for M. japonicus in 42 ‰, however, the activity of arginase increase in 42 ‰. An increase of urea is considered due to the hydrolysis of arginine for the M. japonicus in 42 ‰.
M. japonicus exposed to 0, 0.36 and 1.39 mM nitrite were examined for (1) nitrogenous excretion including ammonia-N excretion, urea-N excretion and organic-N excretion, (2) the levels of nucleotide-related compounds, ammonia, urea and uric acid in tissues, (3) the activities of emzyme involved in uricogenesis like XDH and XOD, and activities of enzymes of involved in urecogenesis like uricase and arginase. Excretions of organic-N, ammonia-N and urea-N increased significantly for the shrimp exposed to 1.39 mM nitrite. Hemolymph urea and epidermis uric acid increased significantly for the shrimp exposed to 1.39 mM nitrite, whereas hemolymph uric acid and epidermis urea decreased significantly for the shrimp exposed to 1.39 mM nitrite. The levels of total nucleotide-related compounds including xanthine and hypoxanthine in the gill increased for the shrimp exposed to 1.39 mM nitrite, whereas the levels of total nucleotide-related compounds including xanthine and hypoxanthine in the hepatopancreas decreased for the shrimp exposed to 1.39 mM nitrite. The activities of arginase, XDH and XOD in the hepatopancreas increased for the shrimp exposed to 1.39 mM nitrite.
In the hapatopancreas, the activities of XDH and XOD of shrimp increased when exposed to elevated nitrite, whereas no significant difference of uricase activity was observed for the shrimp among three treatments. An increase of uricogenesis occurs for the shrimp under the stress of elevated ambient nitrite. An increase of uric acid is considered to be associated with increased oxygen affinity of hemocyanin. Uric acid accumulated in the epidermis is removed along with the epidermis at the time of molting. The activity of uricase shows no increase for the M. japonicus exposed to 1.39 mM nitrite, however, the activity of arginase increase for the shrimp exposed to 1.39 mM nitrite. It is suggested that an increase of urea is through the hydrolysis of arginine for the M. japonicus under the stress of elevated ambient nitrite. Higher activities of arginase in the hepatopancreas and hemolymph, together with increases of hemolymph urea and urea-N excretion indicated an ureogenesis to reduce joint toxicities of metabolic ammonia and incorporated nitrite for the shrimp under the stress of elevated nitrite.
| Identifer | oai:union.ndltd.org:TW/092NTOU5086002 |
| Date | January 2004 |
| Creators | Won-Chung Lee, 李汪聰 |
| Contributors | Jiann-Chu Chen, 陳建初 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 105 |
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