Milda Zita Vosylienė

The Effect of Heavy Metals on Haematological Indices of Fish (Survey)

This article is a survey of our works and works carried out by other authors dealing with the haematological indices of fish and their changes caused by heavy metals and their mixtures. The changes in these indices and their peculiarities depending on the concentrations of heavy metals and duration of exposure of fish to them as well as their physiological and ecological significance are discussed.

STUDIES OF MICRONUCLEI AND OTHER NUCLEAR ABNORMALITIES IN BLOOD OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) TREATED WITH HEAVY METAL MIXTURE AND ROAD MAINTENANCE SALTS

The frequency of micronuclei (MN), nuclear buds and bi-nucleated erythrocytes was analysed in peripheral blood of rainbow trout (Oncorhynchus mykiss), treated with a heavy metal model mixture (HMMM) and with a mixture of road maintenance salts in doses of real metal and salt concentrations in soil near the main Lithuanian highway. The absolute concentration (100%) of the HMMM solution was Cu 0.874; Zn 0.93; Pb 4.7; Ni 0.66; Cr 0.33 and Mn 18 mg/l. Four groups of fish, each consisting of ten specimens, were exposed to 21.79%, 10.89%, 5.45% and to 1.1% mixtures of HMM for 14 days. Additionally, four groups of rainbow trout (10 specimens in each group) were exposed to the solution containing 4.56, 2.28, 1.14, and 0.1825 g/l of road maintenance salt for 14 days and fish in one aquarium were treated with common salt (4.56 g/l). The control group of rainbow trout was kept in an aquarium with artesian aerated water. A statistically significant increase in micronuclei was observed in the rainbow trout after expos...

Alterations in Fish Health State Parameters after Exposure to Different Stressors

The effect of short-term (10-day) exposure of rainbow trout (Oncorhynchus mykiss) to stimuli of different origin (natural — starvation and anthropogenic — chemicals, i. e. heavy metal mixture) as well as to their combined action on their behavioural reactions, morphological parameters and physiological indices was studied and evaluated. Both stimuli induced changes of different degrees in the studied parameters. Starvation induced more expressed changes in morphological indices (decrease in fish condition factor, tissue weight); chemicals induced changes in physiological parameters (decrease in the fish ventilation frequency, increase in “coughing” rate, erythrocyte count, and haemoglobin). Combined effects of two stimuli evoked more significant alterations in the majority of studied parameters (tissue-somatic indices, cardio-respiratory and haematological parameters). Our data suggest that joint action of the two stimuli even of low intensity (concentrations of heavy metals in mixture were similar to con...

REVIEW OF THE METHODS FOR ACUTE AND CHRONIC TOXICITY ASSESSMENT OF SINGLE SUBSTANCES, EFFLUENTS AND INDUSTRIAL WATERS

This article is a survey of methods applied in EU, USEPA, and Environment Canada for the acute and chronic toxicity assessment of chemicals, effluents, and industrial waters. Similarities and differences in aims of these methods, test organisms used, duration of tests are presented and discussed.

Comparative Studies of Sublethal Effects of Ammonia on Rainbow Trout (Oncorhynchus Mykiss) at Different Stages of its Development

Sublethal effects of ammonia on rainbow trout (Oncorhynchus mykiss) were investigated at stages of its development (embryos, larvae, and adult fish) using morphological and physiological parameters. Exposure to 0.006–0.18 mg/l NH3 caused a deceleration of larvae growth: after a 20-day exposure, the total body mass of rainbow trout larvae significantly decreased, and so did the relative body mass at the end of the tests (p < 0.05). Long-term exposure to sublethal concentrations (0.024–0.09 mg/l) of ammonia induced a significant decrease in parameters of red (erythrocyte count, haemoglobin concentration, and haematocrit level) and white (leukocyte count and lymphocyte percentage) blood cells. Those data demonstrated adverse effects of ammonia in sublethal concentrations (similar to those found in ambient waters) on fish at different stages of their development.

Peculiarities of the Physiological Responses of Rainbow Trout (Oncorhynchus mykiss) to Copper

Copper effects on rainbow trout (Oncorhynchus mykiss) were studied using the cardiorespiratory system parameters and haematological indices. A short-term (up to 10 days) and a longterm (6 months) exposure of fish and a wide range of concentrations from 0.05 to 0.5 mg/l of copper ions were examined. The automatic system for fish rhythmogram registration was used: RR interval duration, dispersion (sinusoid arrhythmia), and periodic structure of heart rhythm were measured. Additionally, gill ventilation frequencies and heart rate were measured. Haematological indices (erythrocyte, lymphocyte count, haemoglobin, haematocrit and glucose concentrations) were estimated. It was determined that during short-term exposures low copper concentrations were able to induce reversible changes in cardio-respiratory indices and haematological parameters. High concentration of this metal (0.5 mg/l) caused irreversible changes in these parameters as well as in heart rhythm and rhythm periodic structure. The alterations in th...

Analysis of nuclear abnormalities in erythrocytes of rainbow trout (Oncorhynchus mykiss) treated with Cu and Zn and after 4-, 8-, and 12-day depuration (post-treatment recovery).

The induction of micronuclei (MN), nuclear buds (NB), bi-nucleated erythrocytes with nucleoplasmic bridge (BNb), vacuolated (VacNuc), blebbed (BL), 8-shaped nuclei, bi-nucleated (BN) and fragmented-apoptotic (FA) erythrocytes was analysed in the peripheral blood, cephalic kidney and liver of rainbow trout Oncorhynchus mykiss after 4-day treatment with copper (Cu) and zinc (Zn) mixture solutions and in 4-, 8- and 12-day depuration process. Fish (three treatment and one control group, N=40) were exposed to 0.0625, 0.125 and 0.25 fractions of 96-h LC50, respectively under semi-static conditions. Exposure of O. mykiss to Cu and Zn induced significant increase of MN (in blood in all test groups; in liver 0.125, 0.25 and in kidney 0.25 groups, respectively), NB and BL (in blood and kidney 0.25 group), 8-shaped (in blood 0.25; in liver 0.125, 0.25 and in kidney all test groups, respectively) and VacNuc (in liver and kidney 0.0625 and 0.125 groups). After 4-day recovery, significantly elevated levels of MN (in blood 0.0625, 0.125; in liver and kidney 0.125 group, respectively) and 8-shaped (in kidney-0.0625 group) were observed in fish. Significant recovery was observed in 0.0625 group after 12-day depuration, estimating the formation of MN in erythrocytes of blood, of 8-shaped nuclei erythrocytes in liver and kidney (after 8-, 12-day and 8-day recovery, respectively). Significant decrease of MN in blood (after 8- and 12-day recovery), in liver (after 8-day recovery), of NB in blood and kidney (after 8-day recovery) and of 8-shaped nuclei erythrocytes in blood (after 8 and 12-day recovery), kidney and liver (after 8-day recovery) was determined in 0.25 group. Changes in gross morphometric indices and biological parameters were observed. The binary metal mixture did not induce FA erythrocytes in any tissue at any test concentration.

Ecotoxicity and genotoxicity relating to fish in wastewaters discharged from the Vilnius treatment plant

The toxicity and genotoxicity of untreated raw (RWW) and treated wastewaters (TWW) samples from Vilnius wastewater treatment plant was assessed using fish (rainbow trout) at different stages of development. The survival of larvae and fish exposed to RWW in short-term and longterm tests reduced, whereas gill ventilation frequency, heart rate and relative body mass increase of larvae decreased significantly. The long-term exposure of fish to TWW induced significant decreases in white blood cell count and significant increases in micronuclei in blood of treated Oncorhynchus mykiss. The physical, chemical analysis of oil products (C₁₄-C₂₈), benzo(a)pyrene, suspended solids, and heavy metals (Pb, Cd, Zn, Cu, Hg) in RWW demonstrated that the concentrations of xenobiotics and some heavy metals did not exceed their Maximum Permissible Concentrations in the sewerage system and concentrations of substances in TWW corresponded to their criteria for effluents discharged into receiving waters.

Identification of Aeromonas salmonicida in European perch from North Lithuanian rivers during mass mortalities in 2008

The investigation was carried out to ascertain the cause of mass mortalities in European perch (Perca fluviatilis L.) in North Lithuanian rivers in 2008 that reached a maximum in mid-autumn at a water temperature of 6°C. Marked changes were detected in morphophysiological parameters (spleen-, gill-, liver- and heart-somatic indices), which corresponded to changes in haematological parameters (leukocyte count was significantly elevated or reduced) of the infected fish. The viable bacterial counts in the gill, liver and kidney of infected live fish samples ranged from 2.3±0.3 × 103 to 6.3×00B1;0.4 × 103 c.f.u./g. The BOX-PCR fingerprinting technique was used for characterization and identification of the isolated bacterial strains from liver and kidney of infected perch. The bacterial isolates were identified by sequence analysis of the 16S rRNA gene. Pathogenic Aeromonas salmonicida subsp. salmonicida has been identified as a possible causative agent of the observed mortality in European perch.

Physiological State of Atlantic Salmon (Salmo Salar L.) and Sea Trout (Salmo Tutta Trutta L.) Fry Grown in the Žeimena Hatchery

Physiological states of Atlantic salmon (Salmo salar L.) and sea trout (Salmo trutta trutta L.) fry from the Žeimena hatchery were compared in 1999 and 2000 using a complex of biological parameters. Sea trout fry from the Žeimena hatchery were characterised by a smaller mean body length, mean body mass, and a lower body mass/length ratio as compared to salmon. In June, the condition factor and liver somatic indices of salmon and sea trout were significantly higher than those found in November. These changes in morphophysiological (condition factor, liver somatic index) parameters indicate that biotechnological processes of fish production during the hatching period until June were not optimal. In autumn all biological parameters of fry of both species were found to be characteristic of healthy fish with higher possibilities for life in natural waters.