Prevalence of Eimeria spp. in broiler chicken farms

Abstract

Coccidiosis, a disease caused by protozoa of the genus Eimeria, is one of the most economically important diseases for the poultry industry. Seven species of Eimeria infect the domestic fowl (E. acervulina, E. praecox, E. mitis, E. maxima, E. necatrix, E. brunetti, and E. tenella). In addition, three genetic variants, named operational taxonomic units (OTUs x, y, and z) were recently detected in several countries. These OTUs may represent novel Eimeria species and are antigenically distinct from the seven species already classified. Eimeria infections have a high prevalence in industrial poultry farming and it is unlikely that a flock of intensively reared broilers will not be infected by at least one species of Eimeria. There are few studies related to the epidemiology of eimeriosis in industrially produced birds in Brazil and there is not any study in national territory owing to investigate the presence of Eimeria genetic variants. To determine the prevalence of Eimeria spp. in industrial broiler farms in the western region of the state of Santa Catarina, fecal samples were collected from 64 broiler flocks present in 64 broiler farms (five pools per flock, each containing freshly eliminated fecal samples from 10 birds from 28 to 35 days of age). The samples were collected throughout the shed in a W-shaped path and were preserved in 2.5% potassium dichromate solution at 4º C. Samples were subjected to purification and concentration of oocysts by centrifugal flotation in Sheather´s solution. The sediments resulting from the purification of each of the five pools will be submitted to screening of Eimeria spp. oocysts by microscopy. All sediments will be submitted to genomic DNA extraction and samples negative by microscopy will be submitted to genus-specific PCR. Data will be tabulated and analyzed to determine the prevalence considering the 95% confidence interval. (AU)