BLOOD PARAMETERS IN RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) - SIMULTANEOUS INFLUENCE OF VARIOUS FACTORS

The effect of the simultaneous influence of weight, temperature, densi ty and O-2 concentration in the water on various blood parameters in r ainbow trout (Oncorhynchus mykiss), namely haematocrit (Ht), haemoglob in (Hb), red blood cell (RBC), mean cell, mean cell haemoglobin conten t and mean cell haemoglobin concentration was studied. Nineteen lots w ith average weights ranging from 178 to 372 g were used. Initial densi ty values were 7.2 to 38.8 kg/m(3). Temperature ranged from 15 to 20 d egrees C and O-2 concentration in the water 5.8 +/- 2 to 8.6 +/- 2 ppm . Multiple correlation and regression analyses showed a strong depende nce of Ht, Hb and RBC on the factors considered, the most influential of which was temperature. The relatively low r(2) values obtained, how ever, suggest the existence of additional factors which were not consi dered by us and which might explain the variability found in blood par ameters.