Acta Vet. Brno 2006, 75: 107-113
Nitrite Toxicity to Danio Rerio: Effects of Fish Age and Chloride Concentrations
The aim of the present study was to compare the acute nitrite toxicity for Danio rerio at the age of 20-25 days (larval stage) and 2-3 months (juvenile stage) at various chloride concentrations. The semistatic method according to OECD 203 was used in the tests. The 96hLC50 NO2- value was 386.00 ± 29.75 mg l-1 (D. rerio aged 20-25 days), and 242.41 ± 13.67 mg l-1 (D. rerio aged 2-3 months), respectively, at 19 mg Cl- l-1 in diluting water. We observed an increase in 96hLC50 NO2- in D. rerio of both developmental stages following an increase in Cl- concentration in diluting water. A comparison between the 96hLC50 NO2- determined for D. rerio aged 20-25 days and those aged 2-3 months at different chloride concentrations in diluting water (19; 50; 100 mg l-1) showed a highly significant increase (p < 0.01) in the 96hLC50 NO2- for the younger fish at all chloride concentrations. An exponential relationship between 96hLC50 NO2- values and chloride concentrations in diluting water (I = 0.849) was demonstrated in D. rerio aged 20-25 days while a logarithmical relationship (I = 0.856) was observed in D. rerio aged 2-3 months.
Keywords
Cyprinus rerio, zebrafish, 96hLC50, NO2-, competition NO2- and Cl-, fish size.