INFLUENCE OF THERMAL AND PARASITARY STRESS ON THE ERYTHTROCYTARY HEMOGLOBIN (INDEX M) IN SOME CULTURE CYPRINIDS

C. Misăilă, Elena Rada Misăilă, Gabriela Dumitru

Abstract
The paper analyzes the variation of the M index values (Hb x 10⁶/E) in common carp, silver carp, bighead carp and grass carp during the winter season, as well as a function of the anti-parasitary treatments applied. The results of the polyculture growth experiments on 1 year-old common carp, silver carp and bighead carp (C₁₊) in preventively antiparasitary-treated ponds are discussed, along with those referring to wintering under severe hypothermal and over-density conditions of some 2 year-old common carp, silver carp and grass carp (C₂₊), respectively wintering under over-density conditions (15 t/ha) of some batches of 1 summer-old common carp, silver carp and bighead carp (C₀₊) under mild hypothermal conditions.
In the first experiment, the ponds were prophylactically treated, both during populating operations (April), and during growing with 0.1 mg/l trichlorphon, in two stages, and with 2 kg/ha calcium chloride, twice a week, while the hematological evaluation of the effects was made on samples taken over (6 ex./batch) both in the end of the growing season (November) and in the following spring (April).
The results obtained show that the values of index M are higher in the autochthonous species - the common carp (6.43 - 5.59), comparatively with the grass carp (6.18), bighead carp (4.83 - 6.04) and silver carp (4.43 - 4.37). The "echo" beneficial effect of the anti-parasitary treatments is more clearly evidenced by index M, comparatively with the hemoglobin values. Thus, in April, the Hb values of the treated batch were 16.7% higher than those of the reference, while index M was 35.5% higher in common carp and 4.8 - 12.8% higher in the case of silver carp and bighead carp, respectively.
Under severe wintering conditions, the erythropoiesis yield visibly decreases, so that the value of index M in April is 41.5% higher in common carp and 18.1% higher in silver carp - comparatively with the reference moment (autumn) -, unlike the values obtained under mild wintering conditions, when the levels of index M are comparable with the autumn ones in common carp (104.8%) and silver carp (101.8%) while, in the case of bighead carp and, respectively, grass carp, the values remain inferior to those of the reference.

Key words: hemoglobin, Index M, cyprinids, hypothermy, antiparasitary treatments