The ability of recovery in common carp after nitrite poisoning
2006
Kroupova, H.(Jihoceska Univ., Vodnany (Czech Republic). Vyzkumny Ustav Rybarsky a Hydrobiologicky) E-mail:[email protected] | Machova, J.(Jihoceska Univ., Vodnany (Czech Republic). Vyzkumny Ustav Rybarsky a Hydrobiologicky) | Svobodova, Z.(Jihoceska Univ., Vodnany (Czech Republic). Vyzkumny Ustav Rybarsky a Hydrobiologicky) | Piackova, V.(Jihoceska Univ., Vodnany (Czech Republic). Vyzkumny Ustav Rybarsky a Hydrobiologicky) | Smutna, M.(Veterinarni a Farmaceuticka Univ., Brno (Czech Republic))
The aim of the study was to assess the ability of recovery in common carp after nitrite poisoning and to distinguish the difference in nitrite poisoning of carp at two different chloride concentrations in water. Two groups of carp were exposed to environmental nitrite concentration of 1.45 mmol/L NO2- at different chloride concentrations (group 1: 0.31 mmol/L Cl- and group 2: 3.73 mmol/L Cl-) for 48 hours. After that, they were transferred into nitrite-free water. In the group 1 mortality of 51% occurred during nitrite exposure and further 11% mortality was observed after 24 h in nitrite free water. No mortality occurred in group 2 and control. Nitrite and methaemoglobin concentrations (MetHb) markedly increased in group 1. After 24 h in nitrite-free water, the values mildly but not significantly decreased. After the next 120 h, the values decreased significantly. Exposure to nitrite caused also an increase in plasma K+, ammonia, urea and uric acid concentrations in group 1. On the other hand, values of haematocrit, erythrocyte count and haemoglobin concentration were markedly lower than control values. Nearly no changes were found in the group 2. This shows the positive effect of chlorides on the fish resistance against nitrites.
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