EFFECT OF EXPERIMENTAL COCCIDIAL INFECTION ON CELLULAR IMMUNITY INDUCED BY NEWCASTLE DISEASE VACCINATION IN BROILERS

In order to evaluate the possible immunosuppressive effects of coccidial infection on Cell Mediated Immunity (CMI) of broiler chickens, 640 Ross male day old broiler chicks were randomly divided into 4 equal groups of 160 (each consist of 4 replicates of 40). The negative control group remained unchallenged, while the other three groups challenged with 3 different levels of high, medium and low doses of mixed inoculums of E.acervulina and E.maxima at 15 days of age. For the assessment of CMI, Macrophage Migration Inhibition (MIF) test was performed. For this purpose blood samples were collected at 15, 22, 36 days of age. No significant difference was observed among MIF of different groups at 15 days of age (p> 0.05). At 22 and 36 days of age a significant difference observed among MIF of high dose and control groups (p<0.05). According to the results, it can be concluded that severe coccidial infection may compromise specific CMI activity in broilers.