日本のブロイラー産業におけるコクシジウム感染の調査(1974年および1975年)

抄録

F'ield surveys on coccidial infection in Japdnese broilers were performed with 4, 454 fecal samples in 1974 and 1975. The Eimerian species were identified by a combination of two methods, examination of oocyst morphology and chicken passage test. Oocysts were detected from 57.5% of 1, 896 samples in 1974 and from 69.8% of 2, 558 samples in 1975. Eimeria acervulina was found in 98.1 and 98.9% of the oocyst-positive samples, and E. maxima was found in 11.8 and 10.1% in 1974 and 1975 respectively. The Tenella type oocysts were found in 40.5 and 28.3% of the oocyst-positive samples in 1974 and 1975, respectively. In the chicken passage test of the Tenella type oocysts collected in 1975, E. tenella, E. necatrix and E. praecox were found in 69.8, 9.3 and 74.4%, respectively, in the form of single or mixed infection with two or three species. Annual, seasonal, regional and age differences in oocyst detection rate from 1973 to 1975 were significant at the 1% level. The annual and seasonal differences are considered to be due to the effect of coccidiostats used as one source of variances. Oocyst detection rate increased up to 40 days of age and kept plateau thereafter. E. acervulina oocysts were found at anextremely high rate in all the ages. Oocysts of the Tenella type and E. maxima were found rather low rate in younger ages up to 30 days.