碩士 / 國立海洋大學 / 水產養殖學系 / 90 / Abstract
Litopenaeus vannamei juveniles ( 3.97 ±1.40 g ) were exposed to different concentrations of nitrite-N (nitrite as nitrigon), using the static renewal method at different salinity levels of 15 ppt, 25 ppt and 35 ppt at 18℃. The 24, 48, 72, 96, 120 and 144 h LC50 of nitrite-N on L. vannamei juveniles were 187.9, 144.2, 92.5, 76.5, 67.1 and 61.1 mg/l at 15 ppt；274.1, 244., 224.8, 178.3, 164.3 and 152.4 mg/l at 25 ppt；521.2, 423.9, 375.0, 321.7, 281.2 and 257.2 mg/l at 35 ppt, respectively. As salinity decreased from 35 ppt to 15 and 25 ppt, the susceptibility of nitrite-N to L. vannamei increased by 2.6-4.2 and 1.5-2.6 times. The“safe level”of nitrite-N for rearing L. vannamei juveniles were estimated to be 6.11, 15.24 and 25.72 mg/l at 15, 25 and 35ppt, respectively. The relationship among LC50 of nitrite-N (mg/l), salinity (S, ppt), and exposure time (T, h) is as follow：
LC50=123.0182 + 0.3657S — 0.6072 T (R2=0.9847)
L. vannamei ( 7.31 ±1.44 g ) exposed individually to 0 (control), 0.98, 4.94, 9.87, 19.99 mg/l nitrite-N in 35 ppt r were examined for hemolymph nitrite-N after 1, 3, 6, 12 and 24 h, respectively. Following 24 h exposure to 0.98, 4.94, 9.87, 19.99 mg/l nitrite-N, hemolymph nitrite-N accumulated to 2.86, 5.60, 14.40 and 39.39 mg/l, respectively. L. vannamei following 24 h exposure to 9.87 mg/l nitrite-N at 15 ppt, 25 ppt and 35 ppt , hemolymph nitrite-N accumulated to 14.4, 32.6 and 54.9 mg/l, respectively. As salinity decreased from 35 ppt to 25 ppt and 15 ppt, accumulation of hemolymph nitrite-N increased by 2.26 and 3.81 times. The relationship among hemolymph nitrite-N (C, mg/l), salinity (S, ppt ), and exposure time (T, h) is as follow：
C=50.6742 — 1.3631S + 0.8427T (R2=0.8051)
L. vannamei ( 7.38±1.32 g ) following exposure to 0.98, 4.94, 9.87 and 19.99 mg/l nitrite-N at 35 ppt after 1, 3, 6, 12 and 24 h. Concentrations of hemolymph cortisol, glucose, lactete and the activities of hemolymph GOT and GPT were masured. L. vannamei following exposure to 19.99 mg/l nitrite-N increased its hemolymph cortisol to the highest ( 1.14μg/dl ), glucose to the highest ( 20.6 mg/dl ) and lactate to the highest ( 6.44 mg/dl ) after 6h, 1h and 3h, respectively. L. vannamei following 6 h exposure to 19.99 mg/l nitrite-N increased its hemolymph GOT and GPT activities to 149.2 and 70.1 U/l, respectively. L. vannamei exposed nitrite-N concentration at 19.99 mg/l (lower than safe level) at 35 ppt, experienced primary stress response in 6 h.
| Identifer | oai:union.ndltd.org:TW/090NTOU0086031 |
| Date | January 2002 |
| Creators | Lin, Yong-Chin, 林永慶 |
| Contributors | Chen, Jiann-Chu, 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 | 82 |
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