A SURVEY OF EIMERIA SPECIES IN COMMERCIALLY-REARED CHICKENS IN FRANCEDURING 1994

In a survey of chicken coccidia in France during 1994, samples of litt er were collected from 41 farms. On 31 of these farms, eimerian oocyst s were abundant enough to allow monitoring of their numbers in the lit ter. Peak total oocyst counts on these farms ranged from 16,200 to 1,2 54,000/g of litter, but no coccidiosis was observed. The chickens rear ed without anticoccidial agents in their food (poulets biologiques) pr oduced higher and earlier peak oocyst counts in litter than the chicke ns given medicated food (poulets labels). The oocysts in litter sample s from 22 farms (13 poulet biologique, five poulet label, two standard broiler, one breeder and one layer) of the original 41 were identifie d. Six of the seven eimerian species known to parasitize chickens were found, using combinations of five methods (oocyst morphology, intesti nal lesions, enzyme electrophoresis,. growth in embryonating eggs and prepatent time). Multispecific infections predominated (95% of 22 farm s), up to six species occurring together. Of farms where oocysts were detected, the percentages with each species were: Eimeria acervulina ( 100%), E. mitis (82%), E. tenella (77%), E. maxima (73%), E. praecox ( 45%) and E. brunetti (27%). These appear to be the first definite reco rds off. mitis and E. praecox for France. Although E. necatrix was not found in this survey, it had recently been detected by other workers in France, so that all seven chicken Eimeria species were known to be contemporaneous.