Influence of Frequent Phlebothomy on Blood Iron Concentration, Haematological, Metabolic and Endocrine Parameters in Rams

Frequent phlebotomies, even when only a small volume of blood is taken for diagnostic purposes, can lead to the development of iron deficiency with hematological and metabolic changes. The study aimed to determine the influence of frequent blood loss by phlebotomy on blood iron concentration (Fe), hematology, metabolic and endocrine parameters and their relationships. Blood samples were collected from 30 blood donor rams for 6 consecutive weeks, with approximately 10% of blood collected weekly. Such chronic blood loss resulted in a decrease in Fe. Indicators of iron transport in the bloodstream changed, so the value of total iron-binding capacity (TIBC) and unsaturated iron-binding capacity (UIBC) increased, while the value of transferrin saturation percentage (TS%) decreased. Hematological changes included a decrease in red blood cells, hemoglobin, mean red blood cell volume and hematocrit and a tendency for reticulocyte count and red cell distribution width to increase. Chronic blood loss resulted in a specific metabolic response that included the increase in glucose, cholesterol, triglycerides, aspartate-aminotransferase, and insulin resistance, while thyroxine, triiodothyronine and cortisol decreased and there was a tendency for lactate to increase and BHB to decrease. The mentioned blood parameters correlated with Fe and additionally showed greater changes when Fe was extrapolated to the level of clinical deficit (Fe=9μmol/L). These correlations suggest the need to monitor the metabolic and endocrine status during chronic blood loss, in addition to Fe and erythrocyte indices. Compared with previous results in other animal species, Fe may have a direct influence on metabolic processes in rams.