Acute toxicity of ammonia and nitrite to Pacific White Shrimp (Litopenaeus vannamei) at low salinities
The Pacific white leg shrimp, Litopenaeus vannamei, is a potential species for low salinity inland aquaculture. Due to several independent variables, such as species, age, size, salinity and pH, that must be taken into account, there are gaps in the literature pertaining to the toxicity of ammonia a...
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Virginia Tech
2014
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Online Access: | http://hdl.handle.net/10919/32453 http://scholar.lib.vt.edu/theses/available/etd-05092008-231815/ |
Summary: | The Pacific white leg shrimp, Litopenaeus vannamei, is a potential species for low
salinity inland aquaculture. Due to several independent variables, such as species, age,
size, salinity and pH, that must be taken into account, there are gaps in the literature
pertaining to the toxicity of ammonia and nitrite to shrimp. This study was conducted to
investigate the individual and combined effects of ammonia and nitrite on L. vannamei
postlarvae (25-45 days old) at 10 ppt salinity, 28 C and a pH of 7.8. The independent
variables were salinity, total ammonia as nitrogen (TAN) and nitrite-N (NO2-N),
separately and combined. The TAN experiments were conducted at 18 and 10 ppt
salinity while the NO2-N test was conducted at 10 ppt salinity. Combined TAN and NO2
tests were also conducted at 10 ppt salinity. The LC50 values for TAN at 18 ppt salinity,
TAN at 10 ppt salinity, and NO2-N at 10 ppt were observed to be 42.92, 39.72 mg/L
(2.26 and 2.09 mg/L unionized ammonia-N), and 153.75 mg/L, respectively. When NO2-
N was adjusted to the LOEC level and TAN concentrations were varied, synergistic
effects were observed, with an LC50 calculated to be 28.2 mg/L TAN (1.49 mg/L
unionized ammonia-N). However, when the ammonia level was adjusted to the LOEC
and nitrite was varied, antagonistic effects were observed with an LC50 calculated to be
163.3 mg/L NO2-N. The results suggest that further investigations into the combined
effects of ammonia and nitrite at varying concentrations and lower salinities will be
important in developing â standard operating proceduresâ for the shrimp industry. === Master of Science |
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