Changes in the nucleotide triphosphate/haemoglobin and nucleotide triphosphate/red cell ratios of rainbow trout, Salmo gairdneri Richardson, subjected to prolonged starvation and bleeding

The nucleotide triphosphate/haemoglobin (NTP/Hb) and nucleotide triphosphate/red cell (NTP/cell) ratios of rainbow trout increased during prolonged starvation. A decline was noted in blood lactic acid concentration. Red cell count, haemoglobin concentration and haematocrit also declined. Changes in mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were found not to be significant. The NTP/Hb and NTP/cell ratios of both fed and starved trout rose seven days following a 15% reduction in blood volume by cardiac puncture. A rise in whole blood NTP concentration was found only in the bleeding response of fed animals. No significant change was noted in blood lactic acid concentration. The decline in haematocrit was significant only in the starved group. In both groups, however, red cell count and blood haemoglobin concentration fell. MCV rose whereas MCHC declined in all bled animals. Changes in MCH were not significant in either group. Negative correlations were noted between red cell count and both the NTP/Hb and NTP/cell ratios and between haemoglobin concentration and the NTP/Hb ratio. Positive correlations were seen between the two ratios and between red cell count and haemoglobin concentration.