Its define as natural & biologically active compound/ substances produced by fermentation of streptomyces or actinomadura. Its destroy Emeria spp by inferring balance od most important ion specially sodium & potassium.
The polyether ionophore antibiotics were first discovered in the early 1950s and their anticoccidial activities were recognized in the late 1960s. Because of their broad spectrum of activity and the development of drug resistance to other agents, the ionophores gained widespread usage in the poultry industry soon after their introduction. by this time gradually Polyether ionophores showing their resistance & toxicity in poultry
Because of the unique mode of action of ionophores, development of anticoccidial resistance to ionophores was difficult to produce under experimental conditions and slow to develop after clinical use in the field. In the mid to late 1980s, ionophore-resistant strains of chicken Eimeria spp & ionophore resistance is now common.
Cross-resistance between ionophores is common, although strain differences in coccidial response to specific ionophores have been demonstrated in poultry.
In general, resistance to a monovalent polyether ionophore confers some cross-resistance to other monovalent polyether ionophores, but susceptibility to monovalent monoglycoside and divalent polyether ionophores may be retained now a days.
Ionophores are potentially toxic for highly susceptible species in animal studies. Horses appear to be the most sensitive species, with a monensin LD50 of 1.4 mg/kg, compared with goats (LD50 26.4 mg/kg) and chickens (LD50 214 mg/kg).
Clinical signs occur from acute myocardial and muscle degeneration. Sweating, colic, and ataxia with hindlimb paresis/paralysis are also noted are commonly observed in poultry. Pathologically, focal degenerative cardiomyopathy, skeletal muscle necrosis, and congestive heart failure may be noted.
Ionophore toxicosis can be potentiated with concurrent administration of tiamulin, chloramphenicol, macrolides, sulfonamides, and cardiac glycosides in poultry.
Exposure of horses to ionophores is usually accidental, or resulting from horses gaining access to medicated feed, particularly through feed mill errors. Care should always be taken to prevent highly susceptible animals from gaining access to feeds containing these products.
Lasalocid is well tolerated when fed with tiamulin in poultry.