Acute maduramicin toxicosis in pregnant gilts

Ionophores are used as feed additives for the control of coccidiosis and growth promotion in farm animals. Reports of maduramicin toxicosis in farm animals are scarce. The present work describes an acute maduramicin toxicosis affecting 22 pregnant gilts, 2 pregnant sows and 2 boars, resulting in a total mortality of 65% within 2 days. The clinical and histopathological findings observed shared similar characteristics to acute ionophore toxicosis in pigs, being characterized by severe myodegeneration in skeletal muscle and degenerative changes in the myocardium. Important clinical pathology indices found were elevated levels of CPK and ALT. In contrast to the pregnant gilts, the two pregnant sows completely recovered after 1 month and farrowed 2 months after the intoxication event healthy piglets. The lack of effect of maduramicin on the fetuses might be indicative of poor placental penetration of maduramicin. Moreover, the present work reports for the first time maduramicin levels in livers (0.5 mg/kg) of gilts exposed to lethal concentrations of maduramicin (18.5 mg/kg) in the feed. As the average feed intake of the gilts was estimated to be 3.5 kg feed/day, the mean maduramicin intake leading to the observed high mortality rate was 0.4 mg/kg body weight/day.