effects of the administration of anti-coccidial vaccines and drugs on intestinal lesions and biochemical va ri ables of broiler chicks challenged with experimental coccidiosis

coccidiosis is one of the most important disease in poultry. since using of anti-coccidial drugs or vaccination are considered as the most common preventive measures of this disease, an experiment was conducted to compare effectiveness of these methods. nine hundred and sixty day-old male ross broiler chicks were randomly assigned to eight treatments and fed with a corn-soybean meal basal diet during experimental period. treatments 3 and 4 received salinomycin and diclazuril as coccidiostate, respectively, but did not immunize. chicks in treatments 5 to 8 immunized with anti-coccidial vaccines (including livacox q, paracox 5, livacox t, and iracox, respectively) by drinking water on 5 days of age. chicks in all treatments except treatment 1 were inoculated with a suspension of four eimeria species on 26 days of age. from 28 days of age, blood samples were taken on a weekly and serum concentrations of b-carotene, albumin, globulin, albumin to globulin ratio, vitamin a, and total protein were measured. one week post-challenged, 6 birds in each treatment were slaughtered and intestinal lesions were scored. the results indicated that the birds fed diets supplemented with salinomycine or diclazuril had the highest concentrations of vitamin a. serum concentration of b-carotene was higher in negative control (non-infected) treatment. no significant differences were observed in relation to other serum biochemical values among treatments. it was concluded that serum concentrations of vitamin a and b-carotene could be considered as most important serum biochemical values in coccidian-infected broilers. key words: coccidiosis, coccidiostate, coccidial vaccine, biochemical values, broilers.