Eimeria tenella: Packed blood cell volume, hemoglobin, and serum proteins of chickens correlated with the immune state

Abstract

Single inoculation of birds with 5000 or more E. tenella oocysts resulted in an observable or significant drop in packed cell volume (PCV), hemoglobin values, total proteins, and albumin values which was maximum at 6 to 7 days after exposure. This reduction was proportional to the intensity of the disease which, in turn, depended on the number of oocysts used for exposure. The decrease in PCV was accompanied by a decrease in the hemoglobin values. The use of graded doses of oocysts did not produce similar effects. If the birds were made resistant or immune after prior exposure to E. tenella, these changes were not observed. This suggested that the above parameters could be used as an index of the severity of infection and also indirect indication of the immune status of the birds after challenge exposure. At least 5000 E. tenella oocysts were essential to obtain 100% survival against a challenge infection with 100,000 E. tenella oocysts. A correlation was observed between the PCV and hemoglobin levels and the total serum protein and albumin values in birds inoculated with 5000 or more E. tenella oocysts. No significant leukocytic response was detected in infected birds before or after challenge infection.