Decreased osmotic fragility of red blood cells of Eimeria adenoeides-infected turkeys.

The osmotic fragility of red blood cells (RBC) from Eimeria adenoeides-infected turkey poults was compared with that of RBC from control and water-deprived poults. At different hypotonic NaCl concentrations, lysis of RBC from infected poults was 10 to 35% less on day 4 postinoculation (PI) and 50 to 65% less on day 7 PI than that of controls. Red blood cells of poults deprived of water for 3 days were also resistant to lysis; the percent lysis was roughly the same as that of RBC from infected poults at day 7 PI. Incubating control RBC in plasma from infected poults, in extracts of infected ceca, or at different pH levels did not increase their resistance to lysis, suggesting that neither a stabilizing factor in the plasma that had rapid effect on the RBC nor a transient shift in blood pH was involved. Mean RBC size differed little among infected, water-deprived, and control poults (14.0-14.2 X 8.0-8.1 X 3.8 microns). However, although 3.5% of RBC population of control and water-deprived poults were immature (mid to late polychromatic erythrocytes), only 0.4% of the RBC of infected poults were immature. The data suggest that reduced water intake as well as other factors may be involved in the decreased osmotic fragility of RBC from poults infected with E. adenoeides.