Quantified Effects of Late Pregnancy and Lactation on the Osmotic Stability of Sahel Goat Erythrocytes
Pregnancy and lactation are physiological states mediated by metabolic and endocrine factors capable of affecting erythrocyte osmotic stability. Alteration in erythrocyte osmotic fragility (EOF) during late pregnancy and lactation was investigated in 46 apparently healthy adult Sahel goats weighing 18- 30 kg consisting of 16 non-pregnant dry (NPD), 15 pregnant (PRE) and 15 lactating (LAC) animals. The PRE and LAC were in third trimester and nursing periods, respectively. Packed cell volume, erythrocyte count, mean coruscular volume and EOF were determined with heparinised venous blood using standard methods . Erythrocyte parameters of NPD, PRE and LAC did not vary significantly (p >0.05). The mean fragilities of NPD, PRE and LAC varied significantly (p < 0.05) at saline concentration of 8 g/L, with left and right shifts of PRE and LAC fragility curves from NPD curve at saline concentrations of 7-8 g/L, respectively. At 10-70% haemolysis, mean saline concentrations increased (p < 0.05) by 0.31 ± 0.07 (0.2-0.4) g/L for LAC and decreased (p < 0.05) by 0.19 ± 0.09 (0.1-0.3) for PRE from mean values for NPD, so that the aggregate shift of mean saline concentrations between PRE and LAC was 0.50 ± 0.10 (0.40-0.70) g/L. EOF decreased in late pregnancy and increased during lactation, perhaps, due to changes in the composition of erythrocyte membranes associated with the physiologic states.
Keywords: Erythrocyteosmotic stability, osmotic fragility, late pregnancy, lactation, Sahel goat