Toxicological studies on potentiated ionophores in chickens. I. Tolerance study.

: The tolerance of chickens to monensin (12.5 mg/kg of feed) and maduramicin (3.0 mg/kg of feed) fed at a reduced dose in the presence of the antioxidant duokvin was studied in two experiments including 2 x 200 Tetra-82 broiler chickens. Tolerance was assessed by the appearance of clinical signs indicative of a toxic effect, the number of deaths, the groups' body weight gain, feed and drinking water intake, the aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities, calcium ion, inorganic phosphate and total protein content of the blood plasma, the haematocrit value, and haemoglobin concentration. When applied at a dose that had proved to be optimum in the efficacy studies, neither the monensin-duokvin combination (12.5 mg monensin per kg of feed + 120 mg duokvin per kg of feed) nor the maduramicin-duokvin combination (3.0 mg maduramicin per kg of feed + 120 mg duokvin per kg of feed) exerted a statistically significant influence on the parameters tested.