Open AccessNitrite Toxicity and Methemoglobin Changes in Southern Flounder, Paralichthys lethostigma , in Brackish Water
Author(s) -
Park Jeonghwan,
Daniels Harry V.,
Cho Sung Hwoan
Publication year - 2013
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/jwas.12064
Subject(s) - nitrite , methemoglobin , flounder , brackish water , biology , sodium nitrite , toxicity , salinity , fishery , zoology , hemoglobin , food science , biochemistry , medicine , fish <actinopterygii> , ecology , nitrate
This study was performed to estimate the nitrite toxicity to southern flounder, Paralichthys lethostigma , in brackish water (7.5 ppt of salinity). For a LC 50 test, 20 fingerlings (5.7 ± 0.4 cm) in each aquarium (15 L) were exposed to the concentrations of 0, 1, 5, 10, 15, 30, 60, 120, and 240 mg NO 2 − ‐N/L in duplication for 10 d. Median lethal concentration at 96 h (96‐h LC 50 ) was calculated as 81.6 mg NO 2 − ‐N/L. For a verification test, young flounder (164.2 ± 9.1 g) were exposed to a simulated culture condition in recirculating systems (1000 L). Sodium nitrite was not added to control system, whereas it was added to Treatment system 1 ( TS 1) and Treatment system 2 ( TS 2) to maintain nitrite concentrations of 20 and 30 mg NO 2 − ‐N/L, respectively. The plasma nitrite concentrations of the young flounder in TS 1 and TS 2 were 4.5 and 6.6 mg NO 2 − ‐N/L, respectively, after 2 wk. At this time, the methemoglobin percentages in TS 1 and TS 2 reached 85.8 and 89.7%, and survival rates were 37.5 and 25.0%, respectively. The results of these tests indicate that southern flounder do not concentrate nitrite in blood from the environment, but they seem to be more sensitive to nitrite compared with other species that do not concentrate nitrite.