Selected performance traits in broiler chickens fed on diet with or without added Diclazuril preparation and compared with those in broiler chickens from parent stock hens vaccinated with Eimeria subunits

The effects of two methods of coccidiosis prophylaxis on broiler chicken performance were investigated in three groups of 39 birds each, i.e. 117 individuals in total. Group no.1 comprised chicks from layers immunised with a sub-unit vaccine used in vaccination of layers for passive transmission of Eimeria antibodies to chicks. Group no. 2 comprised chicks from non-vaccinated layers (control group), whereas in group no. 3 there were chicks from non-vaccinated layers and fed on diet with added diclazuril coccidiostat (E 771) for 25 days. At the age of 34 days all birds were individually inoculated (using a probe introduced into the crop) with a large dosis of 510 thousand oocysts from three pathogenic strains of Eimeria sp. (challenge). After 40 days of growing period all birds were slaughtered, processed and the main performance traits were determined, i.e. body weight gain, feed consumption and conversion, mortality, slaughter yield and meat yield. The Economic Performance index (EPI) was also calculated from the experimental data. In birds from vaccinated mothers the determined Eimeria antibody level was reached being regarded as positive in the chicks. The birds in group no. 1 demonstrated by 7.5% higher EPI values in comparison with those non-vaccinated and by 14.4% in comparison with birds given diclazuril coccidiostat in the diet. The above differences were observed until the inoculation of all birds with the large dose of pathogen Eimeria strains. Thereafter, the performance indices in the three groups of broiler chickens were found to be similar.