Monensin Toxicity in Chickens

Abstract

It is common for poultry-flock owners to suspect that feed is at fault when a disease outbreak or production loss coincides with the delivery of a new load of feed. Usually, however, the disease or production drop and the use of new feed are unrelated. Feeding trials at these laboratories have been used on many occasions to resolve this type of problem. Monensin is a biologically active compound that has antibacterial and anticoccidial properties. It is used extensively in the poultry industry to control coccidiosis. Monensin belongs to the ionophore or ion carrier group of antibiotics. These compounds facilitate the transport of alkali metal ions across biological membranes. Monensis preferably transports sodium ions and, as a result of this uncontrolled movement, ionic gradients and concentrations are altered and physiological processes of cell are disturbed (2). Three unrelated cases of poisoning by monensin sodium in improperly prepared feeds are described. Although routine analyses did not detect the cause, feeding trials confirmed suspicions that the feed was at fault; the cause was eventually found. These three flocks of chickens exhibited feed refusal, paralysis, and death. The symptoms started within a day of delivery of a new