The effect of infection with mixed Eimeria species on hematology and immune responses following Newcastle disease and infectious bursal disease booster vaccination in broilers

Background: Coccidiosis is an important parasitic disease of chickens, causing high mortality and morbidity. This morbidity is believed to be correlated with altered population dynamics of blood cells and immunocompromisation. Objectives: This study investigated the effects of mixed Eimeria species (viz., tenella, maxima, acervulina and necatrix) infection on hematology and immune responses following Newcastle disease (ND) and infectious bursal disease (IBD) booster vaccination in broilers. Animals and methods: One-day-old broiler chicks (Hubbard; n = 200) were divided into two equal groups A and B. On day 16, group A was infected orally with Eimeria species (7 x 10(4) sporulated oocysts), whereas group B served as control. Both groups were analyzed for hematological parameters on post-infection days 6-8. Sera from both groups were analyzed for antibody titers against ND and IBD vaccines. On day 8 post-infection, lymphoid organs were also examined. Results: Significantly lower (P < 0.05) levels of plasma proteins, globular volume, hemoglobin concentration, packed cell volume, total erythrocytes, mean corpuscular volume and mean corpuscular hemoglobin concentration were found in infected chickens compared with non-infected control chickens. In addition, the infected group exhibited significantly increased (P < 0.05) numbers of different leukocytes. Infected chickens also showed significantly lower antibody titers against ND and IBD with decreased relative organ weights of all lymphoid organs except spleen. Conclusion and recommendations: Mixed species of Eimeria adversely affected the hematology and immune efficiency of broilers. Thus, inexpensive immune potentiators and hemotonics along with appropriate anti-coccidial medications are suggested to avoid the complications and subsequent economic losses.