Abstract
3 The hypothesis tested was that the feeding of mannanoligosaccharides (MOS) will suppress the signs of a coccidiosis infection in broilers. Two separate experiments were performed in which part of the broilers used were infected with Eimeria tenella. In each experiment there were three treatment groups: a negative control group fed the basal diet and two infected groups fed the basal diet without or with a commercial MOS preparation. The infection of the broiler chickens was successful as based on the caecal lesions, oocyst shedding and schizonts in the lamina propria of the caecum, but did not affect growth performance of the birds. In the infected birds fed the MOS preparation, the number of schizonts was reduced without a decrease in the severity of caecal lesions and without impact on growth performance. It i s suggested that the MOS preparation had enhanced the immunity of the infected birds and thereby had decreased the number of schizonts. It is concluded that this study presents evidence for a protective effect of MOS against coccidiosis infection in broilers.