Control of infection by Eimeria tenella, Eimeria maxima and Eimeria acervulina in broilers with the association of sulfadimethoxine and trimethoprim

Eimeria spp. infections in broiler still cause huge economic losses. An experiment was conducted to evaluate the efficacy of a combination of drugs in the control of multiple infections of these parasitic protozoans in chickens experimentally infected. Five groups of 20 Ross308 broilers at 21st day of life were infected per os with 1 ml of a suspension containing 5000 oocists of Eimeria tenella, 5000 of E. maxima and 10.000 of E. acervulina per liter. At 35th day, the therapy with the association of 200 mg di Sulfadimethoxine and 40 mg of Trimethoprim per ml was subdivided in 4 groups: “A” control; “B” with 0.5 ml/L in drinking water for 5 days; “C” with 1 ml/L for the first day and 0.5 ml/L for 4 days; “D” with 1 ml/L for 5 days, group “E” 2 ml/L for 1 day and 1 ml/L for 4 days. All dead specimens were necropsied and intestinal lesion score was evaluated using Johnson et al. (1970) method. Every day for each group oocyst number were counted on a pool of feces by McMaster method as well as direct observation and enumeration of oocyst were performed on the subjects who died. Clinical signs attributable to Coccidiosis have appeared at 6th day after inoculation and first mortality was observed after 14 days. In the same day the treatments started and mortality go further for 2 days only in the control group. The lesion scores show how the inoculation causes macroscopic lesions referable to E. acervulina and E. tenella, but less obvious for E. maxima, in the relative portions of the gut. The groups treated with different dosages had a highly significative reduction (p<0.001) of lesions compared to the control group. No significative differences (p>0.05) were found between constant dosage (B and D) or variable (C and E). The treatment has seen a good efficacy in reducing mortality, opening a good perspective for the control of these parasites.