The effect of intraperitoneally applied pure mycrocystin LR on haematological and morphological indices of silver carp (Hypophthalmichthys molitrix Val.)

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 and morphological indices. Two-year-old stockfish of silver carp was used for experiments. In the first one, pure Microcystin LR was applied to the fish intraperitoneally in dose of 250 mu g/kg body weight (bw). A pure Microcystin LR dose of 400 mu 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), haematocrit (PCV), haemoglobin concentration (Hb), mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH). The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and total protein concentration (TP) were determined from blood plasma. The pathological image was similar for both experimental groups under study, with the most remarkable impairment of hepatopancreas (enlargement, yellow - brownish colour, injection of vessels or haemorrhages). Histological examination showed large dystrophic and necrobiotic alterations of hepatocytes, as well as of kidney tubuli. Haematological examination showed a highly significant increase of plasmatic enzyme activity (ALT, AST, LDH), as well as a highly significant decrease in TP compared to the control group of fish. Moreover, a highly significant decrease of both haematocrit and haemoglobin concentration was recorded in the first experiment. The results of our study indicate that the intraperitoneally applied Microcystin LR causes mainly a serious impairment of hepatopancreas in silver carp, shown as an increase in activity of plasma enzymes.