Intoxicação por antibióticos ionóforos em animais:[revisão] / Ionophore poisoning in animals: [review]

O uso terapêutico de antibióticos ionóforos em medicina veterinária difundiu-se muito nos últimos anos, com conseqüente aumento no risco de intoxicação em animais. Antibióticos ionóforos são usados como coccidiostáticos e como aditivo em alimentos para animais, com o propósito de estimular o desenvolvimento e o ganho de peso. Os ionóforos mais utilizados na alimentação de animais são a monensina, lasalocida, nasarina e salinomicina. Há uma grande variação na susceptibilidade dos efeitos tóxicos dos ionóforos de acordo com a espécie animal. A intoxicação pode ocorrer quando dosagens elevadas de ionóforos são adicionadas aos alimentos, ou quando ionóforos são incluídos inadvertidamente ou acidentalmente em dosagens não corretas para determinada espécie animal. Casos de intoxicação têm sido descritos em bovinos, ovinos, suínos, eqüinos, cães e aves. Para os eqüinos os ionóforos são extremamente tóxicos. São considerados seguros quando usados nas espécies-alvo, dentro das dosagens recomendadas pelo fabricante.

The therapeutic use of ionophores in veterinary medicine has grown in the last years, with resultant increase in the risk of poisoning in animals. Ionophores are used as food additives as coccidiostacts in several animal species and growth promoter and bloat prevention in ruminants. The most often used ionophores are monensin, lasalocid, narasin and salinomycin. There is a great variation in the susceptibility to the toxic effect of ionophores in different animal species. Poisoning can occur when the dosage is too high or when not correct doses for a certain animal species are given. Cases of poisoning have been described in sheep, swine, horses, dogs and poultry. For horses ionophores are extremely toxic. The use of ionophores is only safe when used accordingly to the instructions of the manufacturer and especially for each animal species. In this paper the most important data regarding clinical-pathological and pathogenic aspects, and also the conditions in which the poisoning may occur are critically reviewed.

Evaluation of zinc against salinomycin toxicity in broilers.

Salinomycin was studied for its toxicity and zinc (80 mg/kg) was assessed for prophylactic and therapeutic management in broiler chicks. Male broiler chicks were randomly divided into 7 groups consisting of 6 chicks in each. Group 1, 2 and 3 were maintained as control, therapeutic dose control (60 mg/kg feed) and toxic dose control (120 mg/kg feed), respectively. Group 4 was fed on feed containing salinomycin therapeutic dose and zinc. Group 5 received feed containing toxic dose of salinomycin. Group 6 and 7 were fed on feed containing toxic dose of salinomycin for the first 4 weeks for induction of ionophore toxicity and for the subsequent 2 weeks, group 6 received zinc and group 7 was fed on feed containing toxic dose of salinomycin along with zinc. Weekly body weights revealed a significant (P<0.01) decrease in toxic controls as compared to group 1, 2, 4 and 5. The activity of glutathione peroxidase, glutathione reductase and catalase, and the values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total proteins, total cholesterol, triglycerides, low density lipoproteins (LDL), urea, creatinine and blood urea nitrogen (BUN) were significantly (P<0.01) elevated in toxic controls, whereas glutathione (GSH) and high density lipoproteins (HDL) were significantly (P<0.01) lowered as compared to group 1, 2, 4 and 5. Following toxicity, zinc supplementation in group 6 and 7, all serobiochemical parameters were revived to normal. Thus, it is enunciated that salinomycin toxicity is due to oxidative damage and use of zinc in feed tends to cure and avoid any accidental toxicity.