No abstract

Two species of common edible fish, common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix), were exposed to a Microcystis spp.-dominated natural cyanobacterial water bloom for two months (concentrations of cyanobacterial toxin microcystin, 182-539 microg/g biomass dry wt). Toxins accumulated up to 1.4 to 29 ng/g fresh weight and 3.3 to 19 ng/g in the muscle of silver carp and common carp, respectively, as determined by enzyme-linked immunosorbent immunoassay. Concentrations an order of magnitude higher were detected in hepatopancreas (up to 226 ng/g in silver carp), with a peak after the initial four weeks. Calculated bioconcentration factors ranged from 0.6 to 1.7 for muscle and from 7.3 to 13.3 for hepatopancreas. Microcystins were completely eliminated within one to two weeks from both muscle and hepatopancreas after the transfer of fish with accumulated toxins to clean water. Mean estimated elimination half-lives ranged from 0.7 d in silver carp muscle to 8.4 d in common carp liver. The present study also showed significant modulations of several biochemical markers in hepatopancreas of fish exposed to cyanobacteria. Levels of glutathione and catalytic activities of glutathione S-transferase and glutathione reductase were induced in both species, indicating oxidative stress and enhanced detoxification processes. Calculation of hazard indexes using conservative U.S. Environmental Protection Agency methodology indicated rather low risks of microcystins accumulated in edible fish, but several uncertainties should be explored.

The aim of this study was to investigate the effect of intraperitoneally applied Microcystin LR to the health condition of silver carp (Hypophthalmichthys molitrix Val.) stockfish by means of assessment of haematological. biochemical and morphological indices.Two-year-old stockfish of silver carp was used for experiments. In the first trial. pure Microcystin LR was applied to the tish intrar.eritoneally in dose of250 ~g' kg· l body weight (bw). A pure Microcystin LR dose of 400 ~g . kg' bw was used in the second experiment. After 48 hours. fish were sampled for blood by cardiopunction to determine the erythrocyte count (RBC

Seasonal variation of water characteristics, predominantly temperature, is considered to strongly affect fish physiology and immunology. In nature, this variation directly influences the life cycle especially in fish parasites, but the infection of parasites is also altered by the host immune response. This study is aimed to analyze the seasonal changes in selected physiological and immunological parameters, the latter a potential measure of fish immunocompetence. Moreover, the seasonal changes in metazoan parasite infection were investigated, and the potential associations between fish physiology, immunocompetence, and parasitism were estimated. No differences in gender were recognized for immunological parameters. The significant differences in the spleen-somatic index were found among fish samples of different seasons indicating higher investment in spleen size in April (after winterizing) and August (post-breeding with low gonado-somatic index [GSI]). The significant seasonal differences in erythrocyte and leukocyte cell counts, as well as in phagocyte count affecting respiratory burst, were recorded. The general trend of leukocyte composition was similar in all seasons investigated; however, the changes in proportion of different neutrophilic cells were reported. The parasite diversity and the infection parameters in parasite communities were highest in spring and early summer. When comparing parasite abundance in infracommunities among seasons, the statistically highest values were observed in April and June for Monogenea, in April and November for Acanthocephala, and in April for Cestoda. The positive correlations between GSI and the parasite abundance of groups with higher infection parameters were found in males. Moreover, the positive association between Monogenea as the dominant parasite group and respiratory burst was observed. The higher investment in condition and the seasonal variation in GSI were associated with a decrease immune function measured by spleen size or leukocyte cell count especially for males suggesting the seasonal energy allocation between immune function and somatic or reproductive investment.

Navratil S., M. Palikova. V. Vajcova: The Effect

Palíková M., J. Mare‰, J. Jirásek : Characteristics of Leukocytes and Thrombocytes of Selected Sturgeon Species from Intensive Breeding. Acta Vet. Brno, 1999, 68: 259-264. Analysis of leukocyte and thrombocyte characteristics in Acipenser baerii, Acipenser stellatus and Huso huso sturgeons at the age of about 200 days kept under intensive breeding conditions is presented. The differential leukocyte count of studied fish species was of lymphocytic character (68.0-73.5% of lymphocytes), and the neutrophilic and eosinophilic granulocytes amounted to 21.8-25.1% and 3.0-4.6%, respectively. Statistically significant (p< 0.05) differences were found between individual sturgeon species in morphometric characteristics of studied cells (i.e. thrombocytes, lymphocytes, neutrophilic and eosinophilic granulocytes). The highest values were found in Acipenser baerii. These results are in good agreement with data on the ploidy in sturgeon species under study. Acipenser baerii, Acipenser stellatus, Huso huso, differential leukocyte count, thrombocytes, lymphocytes, neutrophilic granulocytes, eosinophilic granulocytesThe family Acipenseridae may be divided into two groups with respect to the number of chromosomes and the amount of nuclear DNA. The first group comprises species having a large number of chromosomes (2n = 250). The species A. baerii and A. gueldenstaedti belong to this group. The second group includes, for example, H. huso, A. ruthenus, A. stellatus with lower numbers of chromosomes in their genomes (2n = 118-120) (Vasilyev et al. 1980;Gorshkova et al. 1996;Arefjev and Nikolaev 1991). Several studies have shown correlation between the ploidy in various fish species and the red blood cell size (Arefjev and Nikolaev 1991; Flaj‰hans 1997; Svobodová et al. 1998).The aim of our study was to evaluate interspecies differences in morphological characteristics of leukocytes and thrombocytes in selected sturgeon species (i.e. A. baerii, H. huso and A. stellatus) known for different numbers of chromosomes. Materials and MethodsA total of 10 Acipenser baerii, 10 Huso huso and 5 Acipenser stellatus sturgeons originating from the Fishery Hluboká, Mydlovary farm were sampled (A. baerii in September, A. stellatus a H. huso early in December). All the fish used in the study were clinically healthy without any signs of disease. The fish were kept under intensive breeding conditions in flow-through troughs with controlled environment (water temperature of 20 o C, water oxygen saturation over 80%). Other hydrochemical indicator values assessed in discharge water characterise the environmental conditions suitable for intensive sturgeon culture. The fish were fed complete feeding mixtures. Basic haematological and biochemical parameters have been already published (Jirásek and Mare‰ 1998). Proke‰ et al. (1995ab; studied morphometric characteristics of these sturgeon species with respect to plastic and meristematic signs. Using morphometric characteristics these authors determined the studied species to be pure species.Blood fr...

No abstract

No abstract