Interaction of T-2 fusariotoxin and monensin in broiler chickens infected with coccidia

Field observations suggest that coccidiosis is a common cause of death in broiler chicken flocks fed diets containing sufficient amounts of ionophore antibiotics /monensin, narasin, etc./ and contaminated with mycotoxins, particularly with T2 fusariotoxin. To study this phenomenon, broiler chickens fed diets containing different amounts of T2 toxin and free from monensin, or containing a preventive dose /100 mg/kg of feed/ of monensin were infected experimentally with coccidian cocysts. In all groups fed a diet containing monensin plus T-2 toxin severe clinical symptoms of coccidiosis /blood-stained faeces, etc./ occurred. Deaths and retarded growth depended on the toxin dose and were considerable. In experiment 2 the body mass gain of chicks fed a diet containing monensin and T-2 toxin but not infected with coccidia was inferior to that two compounds is assumed. This seems to be supported by the results of experiment 3, i.e. the finding that the lethal dose of narasin, a compound closely related to monensin both in chemical structure and mechanism of action, proved to be much lower /LD50 = 102 mg/kg body mass/ for chickens fed a diet supplemented with T-2 toxin than for the control chickens /LD50 = 176 mg/kg body mass/. The present results suggest that the feeding of diets severaly contaminated with T-2 toxin may alter the anticoccidial efficacy of monensin.